Biology Review


Loading.... (view fulltext now)





Full text


Biology Honors Scientific Method

• The organized way of using evidence to learn about the natural world

• The goal of science is to investigate and understand nature. Also, to explain events in nature

and to use those explanations to make useful predictions


• They make observations using one or more of their senses to gather information

-Qualitative - Can not be easily counted or measured (Odor or texture)

-Quantitated - Can be easily measure (Like objects)

Interpreting Evidence

• An observation must be understood to be useful

• An inference is a logical interpretation based on proper knowledge and experience

Explaining the Observation

• When faced with a problem, scientists may formulate several hypotheses for why it is


• A hypothesis is a possible explanation for a set of observations or an answer to a scientific


• Hypotheses arise from prior knowledge, logical inferences or imaginative guesses

Designing an Experiment

I. State the problem -What are we trying to learn?


III. Set up a controlled experiment - Only one variable should be changed, others remain


IV. Record and analyze your data

V. Draw a conclusion: evaluate the data and state whether it supports or refutes the hypothesis

Characteristics of Life • All living things are:

-Made of cells


-Based on a genetic code

-Grow and develop

-Obtain and use materials

-Respond to their environment

-Maintain homeostasis

Made of Cells

• A cell is a collection of living matter enclosed by a barrier that separates that cell from its


-Unicellular - Consists of one cell (Bacteria)

-Multicellular - Consists of many cells (Complex organisms)

Life Processes

• Metabolism - All the chemical reactions that occur within the cell of a metabolism.


• Respiration - This is not the same as breathing and is sometimes called cellular respiration.

Chemical bond energy stores in nutrients are released for us by cells

-Anaerobic - Fermentation without oxygen

-Aerobic - With oxygen

• Synthesis - Involves combing simple substances into complex substances.

-Most common is dehydration: Joins two simple substances by removing water. Amino

acids in your food are used to create protein with this process

• Transport - This is not the same as locomotion. This is the movement of materials into and

within a living thing

-IE- Our circulatory system moves oxygen and nutrients into our cells. (Locomotion is

movement, such as plants bending towards the sun or animals moving their bodies)

• Regulation - Control and coordination

-Includes communication, like the endocrine and nervous system

• Assimilation - The process by which materials are incorporated into a living thing.

-Proteins we ingest are used by our bodies

• Nutrition - Obtaining and processing food

-Autotrophs - Make their own food (photosynthesis and chemosynthesis)

-Heterotrophs - Must obtain food

• Growth - An increase in either the size or number of cells. All organism grow during at least

one part of their life cycle.


• Excretion - The removal of all wastes produced by the ells of the body

-We exhale CO2 as a waste product of cellular respiration

-One celled organisms such as ameba excrete wastes through their cell membranes

• Reproduction - Process by which organisms produce new organisms

-This is the one process that is not necessary for the individual but is necessary for the

survival of the specie.

-Can be asexual with one parent or sexual with two parents


• When all life functions are maintained.

• The process by which living things keep a stable internal environment

Images Under the Microscope

• Images under microscope appear upside down and backwards

• When viewing under the microscope, move slide in opposite direction to center

Field of Vision

• Switch to high power from lower power, the field of vision gets smaller but the detail of the

object gets smaller.


• Higher magnification = you need more light




• Cells have been particular structures that perform specific jobs. These cell parts coordinate and

work together just as systems within an organism are coordinated and work together

Cell Theory

• This is one of the fundamental concepts of Biology

-All living things are composed of cells

-Cells are the basic units of structure and function in living things

-New cells are produced from living cells

Exceptions to the Theory

• Viruses can not reproduce on their own, they must be inside a living thing in order to reproduce

• Mitochondria and Chloroplast contain their own DNA and can reproduce


• Specialized cell structures that are formed from many different molecules and perform specific


-Cytoplasm - Transports materials

-Mitochondria - Extracts energy from nutrients in a process called cellular respiration

-Ribosome - Protein building

-Lysosome - Contains enzymes

-Cell Membrane - A thin flexible selectively permeable membrane

-Endoplasmic Reticulum - Modifies components of the cell membrane and modifies

some proteins


-Nucleus - Information center; the nucleus contains the DNA

Plant Cells

• There are two organelles that are found in plant cells but not in animal cells

-Cell Wall - Provides support and structure for the cell

-Chloroplast - Use energy from sunlight to make energy rich food molecules in a process

called photosynthesis

Levels of Organization

• Cells are grouped into tissues > organs > organ systems > organism

• The body is composed of different kinds of cells grouped in ways that enhance how they

function together

• The structures present in single - celled organisms act in a manner similar to the tissues and

systems found in multicellular organisms

Fluid Mosaic Model

• The cell membrane regulates what enters and leaves the cell and also provides protection and


• The core of the cell membrane is a double layered sheet called a lipid bilayer

• Embedded within the cell membrane are protein channels that allow certain molecules to enter

the cell



• Diffusion causes substances to move across a membrane but does not require energy

-All cells contain liquid and are surrounded by liquid

-When molecules are in solution they move constantly

-When the concentration of a substance is different in one of these liquids, it moves from

the area of high concentration to low concentration

-Equilibrium is reaches when the concentration is the same both inside and outside of the



• The diffusion of water through a permeable membrane

-When the concentration of a substance that can not pass through the membrane is lower

on one side of the membrane, water diffuses through the side of the membrane until

equilibrium is reaches

-Water like other substances move from an area of high to low concentration

Osmotic Pressure

• Because cells contain numerous salts, sugars and protein, the concentration of water is usually

lower inside a cell, so water is constantly diffusing into a cell

• The extra water pressure creates osmotic pressure

• Osmotic pressure can cause a cell to burst if they do not have a way to remove water

• Most cells in multicellular organisms do not come in contact with fresh water. So this is not a


• Single celled organisms that live in fresh water have mechanisms to move water out of the cell.

These mechanisms require energy

Facilitated Diffusion

• For molecules that can not pass through, the cell membrane can move through a protein


-Different protein channels allow ions, sugars and salts to cross various membranes

-This process is fast and specific but still moves from areas of high to low concentration

and does not require energy from the cell

Active Transport

• Moves substances from low areas to high areas of concentration. This process requires the cell

to input energy

-Endocytosis - When the cell folds over to take in large molecules

-Phagocytosis - The cell membrane engulfing food. The membrane pinches off, forming a


-Exocytosis - The process where a vacuole fuses with a cell membrane, forcing the

contents out of the cell


• Needs for classification

I. All living things are basically alike in functions

II. There is however a great variety in the ways and means by which different organisms


III. In order to study the variety of life in an organized and systematic manner, the different

kinds of organisms are grouped together or classified on the basis of certain common

characteristics or the relationships they share

• Classification of organisms are based mainly on similarities of structure

I. Some classification is supplemented by other evidence such as:

A. Fossil record

B. Biochemical date - genetic makeup

C. Behavioral information

D. Embryonic development

E. Cellular structure

II. Modern classification is based on the assumption that all present forms of life development

from earlier forms and have have common ancestors. The grouping of organisms suggest

relationships among them that may be the result of common ancestry

Modern Classification Systems

I. Carolus Linnaeus - Father of modern taxonomy

A. Developed the classification system today

B. Based mainly off of structural similarities

II. Binomial Nomenclature

A. Names are in Latin

B. Italicized with the genus name

III.They are first separated into kingdoms


B. Most used is 5 kingdoms

1. Animal - Multicellular organisms ingest food.

2. Plants - Multicellular organisms that make their own food

3. Fungi - Cells are usually organized into multicellular filaments called hypae, They

reproduce by the means of spores

4. Protists - Mainly one celled plants-like or animal-like organisms. They have distinct

nucleus surrounded by a double membrane

5. Monera - Primitive cells, lacking a nuclear membrane (Prokaryotic)

C. Linnaeus System of Classification

1.Kingdom 2.Phylum 3.Class 4.Order 5.Family 6.Genus 7.Species Biochemistry

• The study of organic compounds

Chemical Bonds

• Ionic Bonds - Transfer electrons (Like salt crystals dissolving in water)

• Covalent Bonds - Share electrons

• Van Der Waals Bonds - Atoms attracted to each other

Way to remember: King Philip Came

Over For Good Soup/Salad/Other words



• Has 2 H+ molecules and one O-

• Polar - Has 2 different charges

• Adhesion - Sticks to other things (Like rain on a window)

• Cohesion - Sticks to itself (Like a puddle)


• Measure of H+ (Positive Hydrogen atoms in a solution)

• Scale of 1-14

• 1 - Very acidic (Lots of H+)

• 7 - Neutral (Pure Water)

• 14 - Very little H+ (A Base)

• Buffers - Control pH to prevent sharp changes (Maintains homeostasis)

• Organic - Has carbon and hydrogen ( Like C6H12O6 )

• Carbohydrates - Main source of energy for living things

• Subunits - Sugar (Saccharide)

• Inorganic - No carbon (Like H2O) • Monomer - One, small unit

• Polymer - Big unit, from small units


• Monosaccharide - 1 Sugar (Glucose)


• Polysaccharide- Many Sugars (Starch)

Lipids (Fats) • Store energy

• Made of mostly carbon and hydrogen

• Subunits - 1 glycerol and 3 fatty acids

• Saturated - Max # of hyrdogens; no double bonds in the molecule

• Unsaturated - 1 Carbon double bonded to another

• Polyunsaturated - More than 2 double bonds (Missing 4 or more Hs)


• Regulate cell processes and control rate of reactions inside cells -Enzymes

• Made of nitrogen, carbon, hydrogen, and oxygen

• Subunit - Only 20 different amino acids

• DNA tells amino acids what order to get in to make certain proteins


• Made of protein

• End in “Ase”, like Lactase

• Involved in all chemical reactions

• They are catalysts - Increase rates (speed) of reactions by lowering activation energy

• Substrate/Reaction = Product

• Fits into the enzyme at the active site


• Enzyme substrate complex - When they’re together, the enzyme does not change shape after a

reaction and can be re-used over and over

• Enzyme Reactions are affected by:

• Temperature - Too high/Too low = denatures enzyme

• pH - Too high/Too low = denatures enzyme

• Concentration of Substrate -

• More substrate = Higher concentration = Faster reactions

• Fewer substrate = Lower concentration = Slower reactions






6 +






6 X→







+ H



Reactants Products


Nucleic Acid

• Store and Transmit hereditary information

• DNA and RNA

• Made of carbon, phosphate and nitrogen

• Subunit - Nucleotides

• Nucleic Acid - Carbon, hydrogen, nitrogen, oxygen, phosphates

• Lipids - Carbon and hydrogen

• Proteins - Hydrogen, Oxygen, Carbon and Nitrogen


Leaf Structure

• The structure of a leaf is optimized for absorbing light and carrying out photosynthesis

• To collect sunlight, most leaves have thin flattened sections called blades.

• Leaves are covered on the top and bottom by an epidermis.

• The leaf epidermis is sometimes covered with a cuticle

• The epidermis and cuticle protect leaves from water loss


• The loss of water from a plant through its leaves. Water is lost in ways by being replaced by

water drawn into the leaf through the Xylem

• Xylem - Tubes through which water moves from the roots to the leaves

• Plants keep their stomata open just enough to allow photosynthesis to take place, but not so

much that they lose an excessive amount of water

-Stomata - Are pore like openings in the underside of the leaf that allow CO2 and Oxygen

to diffuse in and out of the cell

-Each stoma consists of two guard cells that control the opening and closing of

stomata by responding to changes in water pressure

-When the pressure is hugh, the outer walls of the cells are forced into a curved

shape and the stoma is opened. Wen pressure is low, the guard cells are not curved

and the stoma closes

• Biochemical processes are necessary to maintain homeostasis in living things. Life is

dependent upon the availability of an energy source and raw materials that are used in the basic


-The energy for life comes from primarily from the sun. Photosynthesis provides a vital

connection between the sun and the energy needs of living systems

• Plant cells and some one celled creatures contain chloroplasts (The site of photosynthesis)

-Photosynthesis uses solar energy to combine the inorganic molecules (CO2 and H20) into

energy-rich organic compounds (Glucose - C6H12O6)

-Oxygen is released into the environment as a result of this process

( ) Song for Photosynthesis



+ 6H


O -> C






+ 6CO


Carbon Dioxide + Water = Sugar and Oxygen

• In addition to Water and Carbon Dioxide, photosynthesis requires light and chlorophyll, a

molecule found in chloroplast

The Reactions of Photosynthesis

• The process of photosynthesis includes the light dependent reactions as well as the Calvin


• Calvin Cycle - Light Independent Reactions

• The light dependent reactions produce oxygen gas and convert ADP and NADP into ATP and


• The light dependent reactions occur in different areas of the thylakoid called Photosystem I and


• The Calvin Cycle uses ATP and NADPH from the light-dependent reactions to produce high

energy sugars.

• The chemical energy stored in the bonds or organic compounds can be used as a source of

energy for life processes. This energy may be released during the process of cellular respiration







-> H



Sugar + Oxygen = Carbon Dioxide + Water + ATP

-ATP - Adenosine Triphosphate

• This energy is temporarily stored in ATP molecules

• This energy from ATP is used by the organism to obtain, transform, and transport materials and

to eliminate wastes.

• In organisms that use oxygen, carbon dioxide and water are released and ATP is produced.


• In organisms that do not use oxygen or if oxygen is not available, less ATP is produced

• With Aerobic - 36 ATP is used

• With Anaerobic - 6 ATP

The Reactions

• Glycolysis - The process in which one molecule of glucose is broken in half, producing two

molecules of pyruvic avid

• When oxygen is not present, a different pathway follows glycolysis. Glycolysis and the

pathway are called fermentation, because fermentation does not require oxygen, it is anaerobic


• The two main types of fermentation are alcohol fermentation and lactic acid fermentation

• Yeast and a few micro-organisms perform alcohol fermentation

• Produces Carbon Dioxide and Alcohol

• Pyruvic Acid -> Alcohol + CO2 + ATP

• Lactic Acid fermentation takes place in cells during exercise when the body cannot supply

enough oxygen to the muscles. The buildup of lactic acid causes a painful burning

sensation (This is why muscles are sore after exercise)

• Pyruvic Acid -> Lactic Acid + CO2 + ATP

• The energy to make ATP comes from Catabolic Reactions that are Exergonic

• (Exergonic = Chemical reactions that release energy)

• (Catabolic Reactions- Breakdown of more complex organic molecules into


Respiration and Photosynthesis

Different Similar Different

Uses: CO2

Uses: H20

Uses: Sunlight

Produces: Glucose

Produces: O2

Occurs in: Chloroplast

Aerobic: (Oxygen + Glucose -> Carbon Dioxide + Water + Energy)

Digestive System

• Made up of digestive tract and accessory glands

• 15 feet/9 Meters long

• Purpose - To acquire energy and nutrients out of the food we eat

• The pathway that food travels through the digestive system:

-Mouth -Esophagus Uses: Oxygen Uses: Glucose Produces: CO2 Produces: H2O Produces: ATP

Occurs in: Mitochondria

< Respiration > Occurs in Cells Chemical Reactions

Needs Enzymes

Involves Energy

< Photosynthesis >

Alcohol Fermentation : C






-> Alcohol + CO



Lactic Acid Fermentation: Lactic Acid + ATP


-Stomach -Small Intestine -Large Intestine -Rectum -Anus Accessory Glands

• Exocrine glands that secrete digestive liquids through ducts into the digestive system

• Salivary Glands

• Pancreas

• ALiver

Mouth and Salivary Glands • Teeth mechanically break up food

• Breaks down food into smaller pieces to increase the surface area so that it can be digested


• Salivary Glands - Produce saliva

• Made up of mostly water which moistens food, making it easier to swallow

• Ptyalin and Amylase are digestive enzymes in saliva which begin the breakdown of simple



• A gullet or muscular tube


-Takes food from the throat and pushes it down the neck and into the stomach (Takes

5-10 seconds


• The thick muscles in the stomach wall contract to mash the food up

• Chemical digestion of protein begins here

• Gastric glands secrete gastric juice which contain digestive enzymes, acids, and mucus

• Pepsin - Begins protein digestion

• Hydrochloric Acid - Produces acidic environment in stomach so digestive enzymes can

work better

• Mucus - Protects the stomach wall from acid

• Digestion here takes about 2-6 hours

Small Intestine • 6 Meters long

• Final digestion and nutrient absorption occurs here over a 5-6 hour period

• In the beginning, mostly digestion is occurring whereas in the end, mostly absorption is


• Villi - Small fingerlike projections that increase surface area of the small intestine which

maximizes absorption/diffusion

-Capillaries - Simple sugars, amino acids, vitamins and minerals are absorbed into the

bloodstream here



• Produces a couple of digestive enzymes that chemically digest or breakdown proteins,

carbohydrates, fats, and nucleic acids in the small intestine

Chemical Digestion:

-Protein -> Amino Acids

-Carbohydrates -> Simple Sugars

-Lipids -> Fatty Acids

-Nucleic Acids -> Nucleotides


• Among many other functions in the body, it produces bile which doesn’t contain any digestive


• Bile is stored in the gall bladder

• Bile emulsifies the fat into smaller globules

(Mechanical Digestion), Which aids in the absorption of fats in the small intestine

Large Intestine

• Any useful substances in the leftovers, such as spare water and body minerals are absorbed

through the walls of the large intestine, back into the blood

• Usually takes about 12-24 hours to move through the large intestine

• The remains are formed into brown, semi-solid feces, ready to be removed from the body

• Over 7 liters of water are released into the digestive tract with secretions throughout a day (this

is much more than the average person drinks). 90% of this water is recovered in the small and


Rectum and Anus

• Feces are stored in the rectum until they can be eliminated/egested

• These are finally pushed through a ring of muscles (the anus) and out of the body

Gall Stones

• Deposits of bile that became hardened stone like structures and can be surgically removed

Disorders of the Digestive System • Heart Burn

-Painful burning sensation in the center of the chest

-Caused when stomach acid moves out of the stomach and into the esophagus

-Happens when you drink or over eat

• Peptic Ulcer

-Holes in the wall o the stomach caused by acid

-For many years, people thought this was caused by stress and spicy food

-Caused by Helicobacter Pylori Bacteria

-Doctors can cure 90% of ulcers with antibiotics

• Appendicitis

-Inflammation of the appendix

-Located below colon/large intestine

-No function in humans

• Diarrhea


-A lot of salts and water can be life threatening

-Can be caused by contaminated water

-Leading cause of childhood death in under-developed countries

The Human Circulatory System • Consists of:

• The heart

• A series of blood vessels and the blood that flows through them

The Heart

• Located near the center of your chest and is composed entirely of muscle

• The size of a clenched fist and contracts roughly 72 times a minute pimping 70 milliliters of

blood each time

Parts of the Heart

• Pericardium - Protective sac of tissue

• Myocardium - A thick layer of muscle in the walls

• Septum - Divides the left side and the right side of the heart

• Prevents oxygen rich blood from mixing with oxygen poor blood

• Upper chamber which receives blood is the Atrium

• Lower chamber which pumps blood out is the Ventricle



• Contractions begin in a small group of cardiac muscle cells

• Located in the right atrium called the sinoatrial node

• Because these cells set the pace for the whole heart, they are also known as pacemakers


• Blood flows through the lungs through the pulmonary artery, where it picks up oxygen and

returns through the pulmonary vein

• Blood then enters through the left atrium and is pumped to the left ventricle, then through the

aorta to the body

• Oxygen rich blood flows to the left side of the heart and is pumped to the body (Systemic


• Blood that returns to the right side of the heart is oxygen poor because the cells of the body

have absorbed so much of the oxygen and are loaded with CO2 (both types of blood are shades

of red)

Blood Vessels

• Arteries - Large vessels that carry blood away from the heart, except for the pulmonary artery,

they always carry oxygen rich blood

-They have thick walls to help them withstand pressure

-Exerted when the heart contracts and pushed through them

• Capillaries - Smallest vessel (the walls are only once cell thick)

-Blood must pass through in single file and the bring the nutrients to the tissues and

absorb CO2 and other wastes

• Veins - Returns blood to the heart and the walls contain connective tissue and muscle like


-They contain one way valves that keep the blood flowing toward the heart

-Many are located near skeletal muscles so when these muscles contract, blood is forced

through the veins


• Blood is made 45% of cells

• Suspended in the other 55%, a straw colored fluid called plasma

• Plasma is 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste


Red Blood Cells

• Transport oxygen and get their color from hemoglobin

• The iron containing protein that binds to oxygen in the lungs and transports it to the tissues

White Blood Cells and Platelets

• White blood cells attack foreign substances or organisms

• Blood clotting is made possible by plasma and proteins and cell fragments called platelets

Blood Types • A, B, AB, O

• Blood can be given to individuals with the same blood type and all blood types can receive O

Blood Pressure

• When the heart contracts, it produces a wave of fluid pressure in the arteries

• The pressure the blood exerts on the artery walls is known as blood pressure

• Blood pressure decreases when the heart relaxes but the system remains under pressure

Measuring Blood Pressure

• Medical workers can measure blood pressure with a cuff placed on the arm

• An average adult’s blood pressure is 120/80

• First number is the systolic pressure: the force in the arteries when the ventricles contract

• Second number is the diastolic pressure: the force in the arteries when the ventricles relax

Disorders of the Circulatory System

• Arteriosclerosis - Fatty acids known as plaque build up on the walls of the arteries

• If the deposits get too big they obstruct blood and can increase blood pressure


• High Blood Pressure/Hypertension - Forces the heart to work harder which may weaken or

damage the heart muscle and blood vessels (Increases risk for heart attack and stroke)

• Heart Attack - When the arteriosclerosis blocks one of the arteries bringing blood to the heart

• Part of the heart muscle begins to die from lack of oxygen

• Symptoms include nausea, shortness of breath, and severe crushing chest pain

• Stroke - Blood clots break free and stuck in one of the blood vessels leading to the brain

• Brain cells die from lack of oxygen

• Can also occur when a weakened blood vessel in the brain bursts

• Prevention - These disorders are easier to prevent than cure

• Exercise, weight control, sensible diet and not smoking seem to be the best ways to keep

the heart healthy

Lymphatic System

• A network of vessels called the lymphatic system

• Collects the fluid that is lost by the blood and returns it to the circulatory system

• Along the length of the lymph vessels are small enlargements called lymph nodes

• They act as filters that trap bacteria and other microorganisms; they can become enlarged

as a result

Respiratory System

• Two meanings: when glucose and oxygen are converted into CO2, water and ATP into the mitochondria

• Oxygen and CO2 are exchanged between cells, the blood and air in the lungs • Nose, pharynx, larynx, trachea, bronchi and lungs



• Filters dust particles in the air

• Hairs lining the entrance to the nasal cavity traps large dust particles

• Mucus, produced by cells lining the system, moistens the air and traps inhaled particles • Cilia sweeps trapped particles and mucus away from the pharynx

• The mucus is either spit out or swallowed Airflow

• Air moves from the nose to a tube at the back of the throat called the pharynx

• This is the passageway for both air and food

• When food is swallowed, a piece of cartilage called the epiglottis covers the trachea

-Trachea - Tube from pharynx

-Vocal Cords - Two highly elastic folds of tissue in the larynx. When the muscles pull the

chords together, the air moving between the folds causes the chords to vibrate

• Air moves the trachea and enters two large passageways n the chest cavity called the bronchi

(Each bronchus leads to the lungs)

• In each lung, the large bronchi subdivides into smaller bronchi which lead to even smaller

bronchi called bronchioles

• The bronchi and bronchioles are surrounded by smooth muscles that regulate the size fo the


• Alveoli - Tiny air sacs at the end of the bronchioles and are grouped together like

grapes. A delicate network of capillaries surrounds each alveoli


Gas Exchange

• Oxygen diffuses through the inner surface of the alveoli and through the capillary to the blood

• CO2 diffuses in the opposite direction

• Very efficient process: inhaled air is 21% oxygen and .04 CO2

-Exhaled air is 15% oxygen and 4% CO2


• The movement of air into and out of the lungs

• Lungs have no muscles attached to them so the large flat muscle at the bottom of the chest

cavity is called the diaphragm

• Because the cavity is sealed, this causes a vacuum and atmospheric pressure causes air to rush

to the lungs

• The system works because the cavity is sealed and if it is punctured, then it is very difficult to


• Breathing is controlled by the amount of CO2 in the blood, not oxygen


• Asthma - Constriction of the bronchioles caused by allergens or exercise

• Emphysema - Loss of elasticity in the lungs

• Bronchitis - Bronchi are swollen and filled with mucus

• Lung Cancer - Particular deadly because it easily spreads to other locations (It metastasizes or



• Metabolic waste is ousted

-CO2 is a waste of cellular respiration

-Water is a waste of cellular respiration and dehydration synthesis

-Mineral salts are produced by many processes

-Nitrogenous wastes

-Result of metabolism of proteins and when proteins are used in cellular


Ammonia: Very toxic

Urea: Less toxic

Uric Acid: Generally non-toxic


• Toxic materials are released by animals

• Toxic materials are sealed and stored in the vacuoles of plants

• Non-toxic wastes are retained, released, or recycled in other metabolic activities

Human Excretory System

• Two kidneys on either side of the spinal column near the lower back

• Two ureter tubes that leave each kidney and cary urine to the bladder

-Bladder - Where urine is stored

-Urethra - Is the tube in which urine travels to leave the body



-Inner: The renal medulla

-Outer: The renal cortex

• Functional unit of the kidney is called the nephron (1 million nephrons in each kidney)

Kidney Function

• Waste containing blood enters the kidney through the renal artery

• Blood travels through the kidney and urea and other wastes & water are filtered out as urea

• The cleaned filtered blood is returned to circulation through the renal vein

Blood Purification

• A complex mechanism that involves three distinct processes

I. Filtration

II. Reabsorption

III. Secretion


• Occurs in the Glomerulus

• Diffusion causes substances to leave the blood and enter the Bowman’s Capsule

• Water, salt, glucose, amino acids and urea are filtered

• Proteins and blood cells remain in the the blood because they are too large to diffuse


• The kidneys play an important role in homeostasis; they regulate blood volume, water content,

blood pH, and remove wastes from the body

• If anything goes wrong, serious medical problems can ensue; humans can only live with one


• If both kidneys fail there are two options:

• Transplant from healthy, compatible donor

• Dialysis blood is removed and pumped through a machine that does the work of a nephron

(Expensive and time consuming - 3 times a week for several hours)

Immune System

• Homeostasis - An organism’s homeostasis is constantly threatened (Failure to respond can

result in disease or death)

• Agents of Disease: V

-Viruses - Common Cold, Chicken Pox, Influenza

-Bacteria - Tetanus, Meningitis, Strep Throat

-Fungi - Athlete’s foot, ringworm

-Parasites - Protists - Malaria, African Sleeping Sickness

- Worms - Tapeworm

Factors of Disease

• Many show up right away or not show up for many years

• Inheritance, Toxic Substance, Poor Nutrition, Organ Malfunction, Personal Behavior

• Person-to-Person (Through coughing, sneezing and physical contact or sexual


• Contaminated food or water

• Exposure to an infected animals (Vectors- Insects tat spread disease via bite)


• A nonspecific response like skin which is the most important nonspecific response. This is the

barrier that keeps pathogens out of the body (even a small cut can become infected)

• Pathogens can enter through the mouth and nose

• Mucus in your nose and throat trap viruses and bacteria

• Cilia push them away from lungs

• Stomach acid and digestive enzymes destroys pathogens

• Body secretions including mucus, saliva. sweat and tears contain lysozyme (breaks down

cell walls of bacteria)

Second Line of Defense

• Inflammatory response (When pathogens enter the body and release toxins)

• Blood vessels near the infection site grow larger and white blood cells leak into the infected


-Phagocytes (Macrophages) - White blood cells that engulf and destroy pathogens

-B Cells - Produce antibodies

-Killer T Cells - Attach to and kill infected cels

-Memory B and T Cells - Remain after an infection, ready to kill the pathogen before you

get sick if you are ever exposed again


• The immune system releases chemicals that raise the body temperature

• Many pathogens can only survive in a narrow temperature range

• This slows or stops their growth and speeds up metabolism in the body to repair damaged


Specific Defenses

• If a pathogen gets past the nonspecific defense, the body starts a defense called the immune


• The substance that triggers this response is an antigen

-A carbohydrate, lipid or protein on the outside of the pathogen that triggers the immune


Humoral Response

• Carried out by B Lymphocytes (B Cells)

• They produce antibodies

-A protein that helps destroy pathogens and are Y shaped and have identical binding sites

-Antibodies attach to pathogens and mark them for phagocytes and other white blood

cells (Keeps them from entering other cells)

Antibody Production

• Specific for each pathogen; B cells each create a different antibody

• When infected with a pathogen, the B cell that produces and makes plasma cells, also produces

the specific antibody needed to destroy the pathogen

• T Lymphocytes (T Cells) Assist the body

Cell Mediated Immunity

• Body cells infected with a pathogen must also be destroyed by T Cells

Organ Transplant Rejection


• They damage or destroy transplanted organs this is called rejection. To prevent rejection

transplant patients are given drugs to suppress the immune system. This leaves the patients

open to other infections.

Permanent Immunity

• Once the body has been exposed to a pathogen, memory B and T cells remain. They are

capable of producing the specific antibody to the pathogen before you ever get sick

Active Immunity

1. Once the body has been exposed to a pathogen memory B cells and T cells remain. They

are capable of producing the specific antibody to the pathogen before you ever get sick.

This is why you can only get certain diseases once in a lifetime

2. Injection of weakened or dead forms of a pathogen is called vaccination. Vaccines cause

the body to produce memory B and T cells without having been infected with the disease

Passive Immunity

1. Travelers are sometimes injected with antibodies produced in animals to give them

protection from certain disease

2. Antibodies can be passed from mother to child through the placenta and through breast



1. Allergies happen when an allergen attaches to a type of immune cell called a mast cell which releases histamine. Histamine causes the sneezing, runny eyes and nose associated with an allergy. Antihistamines are drugs that counteract histamine.

2. The immune system needs to recognize your own tissues and cells as self in order to work effectively. When the body makes a mistake and attacks cells of the body it is an autoimmune disease


3. Acquired Immune Deficiency Syndrome or AIDS happens when one is infected with the Human Immunodeficiency Virus or HIV. The HIV replicates in helper T cells which destroys them. This makes the immune system unable to fight off other diseases The Nervous System

• Controls and Coordinates functions throughout the body and responds to internal and external stimuli


• Transmit electrical impulses

• Sensory Neurons - Carry impulses from sense organs to Central Nervous System • Motor Neurons - Carry impulses from Central Nervous System to muscles & glands • Interneurons- Connect sensory & motor neurons and carry impulses between them

Neuron Structure

• Cell Body - Contains nucleus and much of the cytoplasm (Site of most metabolic activity) • Dendrites - Branches extensions spreading out from the cell body and carries impulses from

the environment or from the neurons towards the cell body. • Axon - Long fiber that carries impulses away from the cell body • Nerves- Bundles of axons and dendrites

• Myelin Sheath- Insulating membrane surrounding the axon on some neurons

Nerve Impulses

• A negative charge builds up on the inside of the cell membrane • The difference in electrical charge is the neurons Resting Potential

• A nerve impulse begins when a neuron is stimulated by another neuron or by the environment • Impulses travel along the axon away from the cell body towards the terminal

The Moving Impulse

• The protein channels on the cell membrane open & sodium flows into the cell • This flow of positive electrons changes the charge of the membrane


• The inside becomes positive and the outside becomes negative • This change in charge is called the Action Potential

• As the impulse passes, the potassium gates close & the resting potential is reestablished (See page 611)


• The strength of an impulse is always the same

• There must be enough strength to cause a neuron to transmit an impulse • The minimum level needed to activate a neuron is called the threshold The Synapse

• At the end of the neuron, the impulse reaches an axon terminal • There is usually another cell at this location

• The small gap between the axon terminal of one neuron and the dendrites of the next is called the synapse

• The terminals contain tiny vesicles filled with neurotransmitters Neurotransmitters

• Chemicals used by neurons to transmit an impulse across a synapse to another cell

• When the action potential reaches the axon terminal, the vesicles release the neurotransmitters which diffuse across the synapse & attach to receptors on the membrane of the next cell

• Action Potential = Impulse

• This stimulates the cell & causes the sodium ions to rush across the cell membrane of the second cell

• A fraction of a second after they bind, the neurotransmitters are released from the cell surface • They are either broken down by enzymes or recycles back to the axon terminal

The Nervous System Continued • Divided into two major divisions

• Central nervous system is the control center of the body and relays messages and processes & analyzes information


Brain and Spinal Cord

• Wrapped in 3 layers of connective tissue known as meninges • The space between the layers are filled with cerebrospinal fluid • Fluid bathes the brain and spinal cord and acts as a shock absorber

• It allows for the exchange of nutrients & waste products between the blood & nervous tissue • Cerebrum- Voluntary or conscious activities of the body (Site of intelligence and learning) • Cerebellum- Located at the back of the skull - (Coordinates & Balances the action of muscles • Brain Stem- Connects the brain & spinal cord (Controls most important bodily functions

including blood pressure, heart rate, breathing and swallowing) Thalamus & Hypothalamus

• Found between the brain stem and the cerebrum

• Thalamus receives messages from the sense organs - Relays the information to the proper region of the cerebrum

• Hypothalamus recognizes hunger, thrust, fatigue, anger and body temperature Cerebrum

• Divided into the left & right hemispheres

• Each hemisphere divided into regions called lobes • Left hemisphere controls right side and vice versa Spinal Cord

• Main communication link between the brian and the rest of the body • Reflexes are processed directly to the spinal cord

• Reflexes are quick automatic responses to a stimulus • Reflexes allow for immediate response to danger Peripheral Nervous System

• All nerves that are not part of the brain or spinal cord • Can be divided into two divisions

• Sensory Division transmits impulses from the sense organs to the central nervous system to the muscles or glands


• Somatic- Controls activities that are conscious control; movement of skeletal muscles • Autonomic- Controls activities that are NOT under conscious control like heartbeat,

digestive system, blood vessels, etc.

• Autonomic divided into two parts that have opposite effects on the organs they control • Sympathetic and Parasympathetic

• Heart rate is increased by sympathetic and decreased by parasympathetic

The Endocrine System • Involved with regulation • Made up of glands

• Glands release their products into the bloodstream • The products broadcasts messages throughout the body Hormones

• The products released by the endocrine system are hormones • Hormones bind to chemical receptors on cells

• Cells that have the receptors are called target cells Regulation


Peripheral Central

Motor Sensory Brain Spinal

Autonomic Somatic

Sympathetic Parasympathetic

Cerebrum Cerebellum


• If the cell receptors are not present on the cell, the cells will not respond to the specific hormone


• An organ that produces and releases a substance or secretion

• Exocrine glands release their secretion through tubes called ducts (Sweat & Tears) • Endocrine releases secretions (Hormones) directly to the blood stream

• Thyroid - Regulates metabolism

• Parathyroid - Maintains blood calcium levels • Thymus - T-Cell production

• Adrenals - Stress

• Pancreas - Insulin and glucagon blood sugar levels

• Ovaries - Egg productions and female secondary sex characteristics • Testis - Sperm productions and male secondary sex characteristics Disorders

• Diabetes - When the body does not produce enough insulin & blood glucose remains high • Hypoglycemia - When the body does not produce enough glucagon & glucose remains low

Skeletal System

• Names are a network of living cells and protein fibers • They are surrounded by calcium salt deposits

• Bone marrow is the soft tissue within the cavities of bones

• Red marrow is where red blood cells and some white blood cells and platelets are produced Development of Bone

• Fetuses are composed of mostly cartilage

• Cartilage is a network of protein fibers, tough collagen, and flexible elastin fibers • Cartilage does not contain blood vessels

• Cartilage is replaced by bone during a process called ossification Ossification


• Osteoblasts - Creates bones • Osteocytes - Maintains bones • Osteoclasts - Breakdowns bones Types of Joints

• Immovable - Allow no movement - Joints in skull • Slightly Moveable - Allow restricted movement

• Free Moveable - Permits movement in one of more directions Structure of Joints

• Cartilage is found at the ends of bones in joint • It protects them as they move

• Joints are surrounded by a fibrous capsule • This helps hold the bones together

• The capsule consists of two layers • Ligaments hold the bones together

• Synovial fluid lubricates and allows the ends of the bones to slip past each other Types of Muscle Tissues

• Skeletal (Aka Striated) usually attached to bones • Responsible for voluntary movement

• Smooth - usually not under voluntary control

• Muscles that are found in stomach, blood vessels, small & large intestine • Cardiac - Found in only one place in the body; the heart

How Muscles & Bones Work Together

• Individual muscles can only pull in one direction

• Skeletal muscles are connected to bones by tough tissue called tendons • Tendons pull on bones & make them work like levers

• Work in opposing pairs (One contracts, One releases) Diseases

• Arthritis - Inflammation of the joints • Tendonitis - Inflammation of the tendons


• Osteoporoses - Brittle bones

Reproduction System

• Asexual - Done by single organisms (Amoebas)

• Four Types: Binary Fission - Where the cytoplasm is equally divided (Amoeba and paramecium)

• Budding - When the cytoplasm is unequally divided (Yeast and Hydra)

• Regeneration - When a missing part of the organism can regrow (Starfish, planaria and lizard tails only)

• Vegetative Propagation - Form of asexual reproduction in plants • Sexual - Two cells from different parents combine to make one organism • Gonads - The male & female reproductive structures that contain hormones

• Ovaries & Testes (Do not become active until puberty)

• Sexual Maturity - When reproductive system becomes fully functional Male Reproductive System

• FSH & Testosterone stimulates the development of sperm

• Sperm - One celled organisms that carry out genetic information of the father • 2-6 ML of sperm contain more than 200-600 million sperm

• Main structures that deliver sperm • Testes - Make sperm

• Epididymis - Where mature sperm are stored • Vas Deferens - Sperm travel through here • Urethra - Exit way for sperm/urine

• Penis - Where urethra passes through Female Reproductive System

• Ovulation - Egg is released

• When follicle is matured, egg is released • Egg is swept from ovary into the fallopian tube


• Fertilization can only happen in the fallopian tubes • After a few days, egg is passes into the uterus

• Lining of uterus is ready to receive fertilized egg & nurture development of the embryo • FSH & LH stimulate cells in ovaries to produce estrogen

• Follicles are the clusters of cells that surround a single egg

• Follicles help an egg mature for release into the reproductive tract

• Females are born with 400,000 immature eggs (Primary follicles) and do not produce any more eggs in her lifetime. Only 400 eggs will actually be released

• Ovary - Produces eggs

• Fallopian Tubes - Egg travels through and fertilization happens here • Uterus - Where the fetus grows & develops

• Cervix - At the bottom of the uterus

• Vagina - Birth canal/ Baby travels through here while being born Menstrual Cycle

• Occurs after puberty

• Regulated by FSH, Estrogen, LH, Progesterone

• Controlled by negative feedback of endocrine system & reproductive system • 4 Stages :

• 1 Follicular stage - Hormones cause follicle to develop into a maturity. Estrogen makes lining in uterus thicken to receive a possibly fertilized egg. Development of an egg takes 10 days in this phase

• 2. Ovulation Phase - Flood of FSH & LH are released & cause follicle to rupture and releases the egg into fallopian tubes. this is the shortest phase in the cycle

• 3. Luteal Phase - Follicle turns yellow (Corpus Luteum) & releases estrogen &

progesterone to stimulate cell growth & tissue development in fetal lining. Chances for fertilization are greatest during first 2 days of the luteal phase

• This phase is 10-14 days after completion of last menstrual cycle

• 4 Menstruation - If fertilization does not occur, within 2-3 days of ovulation, egg wil lpass through the uterus without implantation. Follicle will break down & release less estrogen &


progesterone. Lining of uterine wall will detach and with blood, the unfertilized egg will pass through the Vagina. This stage lasts 3-7 days (The first say of menstruation begins new cycle)

• Steps of Fertilization and Implantation I. Ovulation

II. Fertilization III. Zygote IV. 2 Cells V. 4 Cells

VI. Morula (A solid ball of about 64 cells) VII. Blastocyst - A hallow ball of cells

VIII. Blastocyst attaches to and then implants into the uterine wall.

• Gastrulation - The formation of three cell layers called the ectoderm, mesoderm and the endoderm

• Neurulation - The first step in the development of the nervous system

• Placenta - The chorionic villi and uterine lining form a vital organ called the placenta which is the connection between the mother and embryo that acts as the embryo’s organ of respiration, nourishment and excretion.

• Across this thin barrier, oxygen and nutrients diffuse from the mother’s blood to the embryo’s blood and CO2 and metabolic wastes diffuse from the embryo’s blood to the mother’s blood.

• After eight weeks of development, the embryo is called a fetus. By the end of three months, most of the major organs and tissues of the fetus are fully formed.


• Division of chromosomes followed by the division of cytoplasm (Cytokinesis) resulting in two identical daughter cells

• Plants and animals perform mitosis • Structures Involved:


• Cytoplasm, Chromosomes, Nucleus, Cell Membranes, Centrioles, Spindle Fibers • Purpose: Reproduction for simple creature or growth and repair

• Five phases of mitosis:

I. Interphase - Cell is growing, performing metabolism

II. Prophase - Nuclear membrane disappears & chromosomes roll

III. Metaphase - Chromosomes line up in the middle (Think M for meta, M for middle) IV. Anaphase - Chromosomes pull apart (A for ana, A for apart/away)

V. Telophase - Two cells form

• Start with 1 cell, end with 2. Start with 46 chromosomes and end with 46, caused by chromosomes replicating.

• Haploid/Monoploid - Cell that has one set of chromosomes (Like sperm/egg or gametes) • Diploid - Cell with two sets of chromosomes (Every cell in your body)

• Chromosome - Contains DNA

• Chromatid - One of two identical “sister” parts of a duplicated chromosome • Centromere - Region of a chromosome where the two sister chromatids attach • DNA - Genetic information/ Deoxyribonucleic acid

• Karyotype - Pictures of chromosomes

• Plant cells have no centrioles, but have spindle fibers and they cannot break a cell wall. They form a cell plate instead.



• The process that results in the production of gametes

• Cells in gonads (Testes and Ovaries or Anther and Ovary) perform meiosis

• Structures Involved: Cell Membrane, Nucleus, Chromosomes, Centrioles, Single Fibers, Cytoplasm

• Start with 1 cell, end with 4 cells. Start with 46 chromosomes, end with 23 chromosomes. Caused by chromosomes replicating. The purpose is to form gametes - Monoploid/Haploid cells

• Phases:

I. Interphase I - DNA replicates forming duplicate chromosome II. Prophase I - Chromosomes pair with homologous chromosomes III. Anaphase I - Homologous chromosomes pull apart

IV. Telophase I - Nuclear membrane forms 2 diploid cells V. Prophase II - Nuclear membrane disappears

VI. Metaphase II - Chromosomes line up in the middle

VII. Anaphase II - Chromatids suppurate & move to opposite ends VIII. Telophase II - 4 Haploid cells form

• Cytokinesis - Division of cytoplasm

• Sister Chromatids - Chromosomes and its exact copy. It looks like this: )(

• Homologous Chromosomes - Chromosome with corresponding chromosome from opposite parent

• Looks like this: )( )(


Sexual Reproduction in Plants

• Cones and flowers are the gametophyte (gamete making) parts of plants

• Conifers or Gymnosperms : There are male and female cones fertilize eggs in the female cone and seeds are formed

• Angiosperms or flowering plants: Flowers are produced at certain times of the yea • Stamen is the male part which includes:

• Anther - Where pollen is formed during Meiosis • Filament - Stem like structure which holds the anther • Pistol - Female part of the flower which includes:

• Stigma - Top of the pistol where pollination takes places

• Style - Leads from stigma to the style pollen tube run through here • Ovary - Contains the ovule where fertilization takes place


• Study of heredity

• How inheritance is passed from one generation to another • Discovered by Gregor Mendel

Gregor Mendel


• Studies seed color, plant height and texture • Trait - Specific characteristics

• Crossed plants with each of the 7 characteristics and studied their offspring • Called parents “P Generation” & offspring “F1 Generation”

• Offspring of crosses between parents with different traits are called hybrids

• Mendel has a group of true seeds which mean if they were allowed to self pollinate, they would produce seeds exactly like themselves

• Performed his experiments by removing the stamen off each flower so they could not self pollinate

• He put the pollen from other people on the female part of each flower (Selectively Cross pollinated them)

• The offspring did not blend the traits of the parent • Tall and short plants did not make medium plants • They had the traits of one parent

Mendel’s Conclusion

• Biological inheritance is determined by factors that are passed from one generation to the next • The principle of dominance states that some alleles are dominant and others are recessive Segregation

• Mendel now wondered what happened if the recessive traits disappeared • He then allowed the 7 F1 Generation plants to produce an F2 Generation • The recessive traits reappeared

• One fourth of the plants in the F2 possessed the gene

• When each F1 plant flowers, the two alleles are segregated from each other. So that each gamete carries only a single copy of each gene.

• Therefore, each F1 Plant produces two types of gametes

• Those with the allele for tallness & those with the the allele for shortness Punnett Squares

• Homozygous - Two identical alleles for the same trait (TT) • Heterozygous - Two different alleles for the same trait (Tt)


• Phenotype - Physical characteristics • Genotype - Genetic makeup


• When Mendel performed his F2 Generation crosses, the ratios always came out 3:1 • You need to do a great many crosses to these ratios

• Just like flipping a coin should result in a 50/50 ratio, the #s only come out this way if the coin is flipped a large amount of times

Other Types of Dominance

• Incomplete Dominance - 1 Allele is not completely dominant over the other • Heterozygous - Somewhere between the two

• Homozygous - Hair straight, curly or wavy

• Codominance - Both alleles contribute to the phenotype - red & white flowers give pink offspring

• Multiple Alleles - Many genes have 2 alleles (Rabbit fur color) • Polygenic Traits - Interaction of several genes (skin color) Inheritance of Traits

• Offspring inherit a combination of traits & characteristics from their parents • At first, there is a process of random recombination of these traits • Environment can modify the physical expression of these inherited traits • Information is stored in nucleus of cell

• Heredity - The passage of these coded instructions from 1 generation to the next Gene Expression & Cell Differentiation

• Hereditary information is in genes; genes are in chromosomes; chromosomes are in cells • An inherited trait can be determined by first generation genes

• Single genes can influence first traits

• A human cell contains thousands of different genes in the nucleus DNA - Molecule of Heredity

• DNA - Molecular basis of heredity


• Genes are segments of DNA molecules

• DNA molecules is made of a sequence of sub-unites called nucleotides (made up of nitrogen base [A,G,C,T] )

• Number and Sequence of these subunits determines chemical structural properties of DNA • Genetic information that underlies heredity is uncoded in genes as a string of molecule bases • Sequence of bases in a DNA molecule provides a template for replication which will produce

identical DNA strands DNA Replication

• Weak chemical bonds between bases of DNA

• It can open up (Unzip) forming a template for a new molecule

• A new molecule forms by pairing each base on the template with each complementary pare (A and T, G and C)


• Random alteration of DNA

• Can be passes to every cell derived from the mutated parent by cell division • Can produce new inheritable characteristics

• In gametes (Sex cells), can be passes to future generations • Mutations in other cells can only be passes onto other body cells • Can result from change in DNA sequence

• Inserting, Deleting, or Substituting DNA segments can alter genes • Mutations may be caused by radiation and certain chemicals Correcting Errors of Replication

• Biological research increases our knowledge in diagnosis, prevention, and treatment of diseases which may include genetic disorders

• Modern technology allows people to control or to cure some genetic diseases of plants and animals





(Deletion or subtraction- Frame Shift - Take “A” out -THE FET CAT ARE THE RAT

(Substitution - Point - Take “a” out and put “e” in). From Genes to Protein

• Work of a cell is carried out by many different molecules it assembles (mostly proteins) • DNA contains codes to synthesize thousands of proteins that each cell requires

• This code is contained in the sequence of many DNA base pairs • Sequence of 3 bases (Called a Codon) represents a single amino acid

• Amino acids - The building blocks of priteins

• 20 Different Amino acids each with their own properties and structures) RNA

• Messenger RNA (mRNA) - Carries the message from the nucleus to the ribosome • Proteins are synthesized in the ribosome

• Ribosomal RNA (rRNA) - Found in the ribosome/ Type of RNA that combines with proteins to form ribosomes)

• Transfer RNA (tRNA) - Carries a single amino acid and attaches to mRNA

• Differnece between DNA and RNA: • RNA is a single strand

• RNA contains different sugar called Ribose

• RNA does not have the base Thymine; it is replaced by the base Uracil

• DNA needs a way to send messages to ribosomes without leaving the nucleus • mRNA is the complimentary DNA pair

• tRNA attaches its amino acids to protein From Genes to Proteins

• DNA molecule will unzip, exposing a template for the production of mRNA • mRNA leaves the nucleus and goes to the ribosome


• tRNA reads the code and attaches the amino acids in the correct order to create the new protein • Protein Synthesis - Transcription and Translation

• Transcription - Synthesis of an RNA molecule from a DNA template

• Translation - Process by which the sequence of bases of an mRNA is converted into the sequence of amino acids of a protein

• A specific sequence of amino acids produces a long folded chain forming a protein molecule • The shape of the protein determines the function of the protein

• Since the genes that code for the protein of the offspring are similar to the parent, the structure and function of the proteins will also be similar

• Similar DNA

• This simultaneously accounts for offspring resembling their parents

Identifying Genes of Interest • Plant and animal breeding

• Improvements in cultivated plants and domestic animals haver been produced for thousands of years through selective breeding

• Cultivated plants that are resistant to disease produce greater yields to food

• Domestic animals with a desirable trait can be maintained, those with an undesirable trait can have it removed

• New varieties of plants and animals have been genetically engineered • Manipulating genetic instructions produces new characteristics • Knowledge of genetics makes possible new fields of health care

• Mapping of genetic instructions make it possible to detect defective genes and possibly aid in the development of preventative measures to fight

• Hormones and enzymes from genetically engineered organisms, such as bacteria, reduce cost and side effects of replacing missing body chemicals

• Cloning increases the number of identical cells without changing the genetic content • Recombinant DNA technology


• The characteristics produced by segments of DNA technology has positive and negative implications

Gel Electrophoresis is a technique used for the separation of DNA, RNA and protein molecules.

Evolution - Theory

• Evolution is the change of species over time. This theory is the central unifying theme of biology.

• The basic theory of biological evolution states that the Earth’s present day species developed from earlier, distinctly different species.

• Evolutionary changes may occur in structure, function and behavior of population over time. Supporting Observations

• The geologic record contains fossils that indicate that simple organisms evolved into increasingly complex multicellular organisms.

• Comparative studies of molecular and structural similarities between organisms indicate ancestry.

Evolution by Natural Selection

• Natural selection is the consequence of many interactions. • Overproduction of offspring and variations among offspring.

• Adaptive value of certain structural, functional and behavioral variations. • Struggle for survival.

• Competition for a finite supply of resources.

• Selection by changing environment of those offspring best adapted for survival and reproductive success.

• The proportion of individuals that have advantageous characteristics will increase. • Behaviors also evolve through natural selection of they lead to greater reproductive

success. This had led to the broad patterns of behavior exhibited by organisms. • Over time, new species of organisms may form.

Genetic Basis of Evolution


• Random mutations of genes in reproductive cells lead to new characters in offspring. If they occur in other cells, they can be passed on the other body cells only.

• These lead to variation of organisms within a species which increase the likelihood that at least some members of the species will survive under changed environmental condition.

Evolutionary Patterns

• Evolution does not necessitate long-term progress in some set directions. It may be compared to the growth of a tree.

• Evolution of species may process with little or no change (some branches survive from the beginning)

• Some species may die out all together -extinction

• Other species branch repeatedly, sometimes giving rise o more complex organisms. • Extinction of a species occurs when it lacks adaptive characteristics for survival in the

changing environment.

• Fossil evidence indicates that extinction of species are common. Most species that live on Earth, no longer exist.

Human Influence on Evolution

• For thousands of years, selective breeding for particular traits in cultivated plants and domestic animals has resulted in new varieties.

• In recent years, genetic engineering has been used to produce new varieties of plants and animals.

• Organisms with short reproductive cycles are most affected by human activities. • Pathogens in an antibiotic environment.

• Insects in a pesticide environment. Evolution has Led to Biodiversity

• Biodiversity increases the chances that at least some species will survive in the face of large environmental changes.

• Biodiversity increases the stability of an ecosystem. Origins of Life


• It is thought by many scientists that life on Earth began billions of years ago as simple, single celled organisms.

• Starting about a billion years ago, these evolved into increasingly complex multicellular organisms.

Types of Evolution

• Gradualism- The gradual change over a very long period of time.

• Punctuated Equilibrium - A dramatic change in the environment leads to rapid change in organisms.

• IE: The death of the dinosaurs. Ecology

• The fundamental concept of Ecology is that living organisms interact with and are dependent upon their environment and each other.

Levels of Organization

• The components of living systems, from single cell to an ecosystem, interact to maintain balance

• The most fundamental level is a single organism

• Groups of organisms belonging to the same species form a population • All the populations in an area form a community

• The living things and the physical environment that influence them form an ecosystem • The portion of the Earth that can sustain life is the biosphere

• Organelles-Cells-Tissues-Organs-Organisms-Population-Community-Ecosystem-Biosphere Definition of an Ecosystem

• An ecosystem involves the interaction between abiotic and biotic factors.

• Abiotic - Includes physical and chemical factors that influence an organism’s ability to live and reproduce.

• Biotic - Includes all the living things that directly influence each other and the non living environment



Related subjects :