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1 Biology

Sylvia S. Mader

Michael Windelspecht

Chapter 1 A View of Life

Lecture Outline

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1.1 How to Define Life

• Biology

is the scientific study of life.

• There is great diversity among living things.

• Living things:



are composed of the same chemical elements

as nonliving things.



obey the same physical and chemical laws that

govern everything in the universe.

(3)

Diversity of Life

3

(4)

Characteristics of Life

1. Living things are organized.

• The levels of biological organization range

from atoms to the biosphere.

• The

cell

is the basic unit of structure and

function of all living things.



Unicellular or multicellular

• Each level of organization is more complex

than the level preceding it.



As biological complexity increases, each level

(5)

Atom

Smallest unit of an element composed of electrons, protons, and neutrons

oxygen

(6)

Atom

Molecule

Union of two or more atoms of the same or different elements

(7)

Atom

Molecule

Cell

The structural and functional unit of all living things

oxygen methane

(8)

Atom

Molecule

Cell

Tissue

A group of cells with a common structure and function

oxygen methane

plant cell epidermal tissue

nerve cell

(9)

Atom

Molecule

Cell

Tissue

Organ

Composed of tissues functioning together for a specific task

(10)

Atom

Molecule

Cell

Tissue

Organ

Organ System Composed of several organs

working together

(11)

Atom

Molecule

Cell

Tissue

Organ

working together Organism An individual; complex individuals contain organ systems

(12)

Atom

Molecule

Cell

Tissue

Organ

Population Organisms of the same species in a particular area

(13)

Atom

Molecule

Cell

Tissue

Organ

Community Interacting populations in a

particular area

(14)

Atom

Molecule

Cell

Tissue

Organ

particular area Ecosystem A community plus the physical environment

(15)

Biosphere Regions of the Earth’s crust,

waters, and atmosphere inhabited by living things

Ecosystem A community plus the physical environment

particular area

Organism An individual; complex individuals contain organ systems

working together Organ

Tissue

Cell

Molecule Union of two or more atoms of the same or different elements

Atom Smallest unit of an element composed of electrons, protons,

(16)

Characteristics of Life

2. Living things acquire materials and energy.

• Energy

is the ability to do work.



Energy is required to maintain organization and

conduct life-sustaining processes such as chemical

reactions.

• Metabolism

is all the chemical reactions that occur in a

cell.



The sun is the ultimate source of energy for nearly all

life on Earth.

• Plants, algae, and some other organisms capture solar

energy and perform photosynthesis.

(17)

Acquiring Nutrients and Energy

17 f.

e.

d.

c.

b.

a.

(18)

Characteristics of Life

3. Living things maintain homeostasis.

• Homeostasis

is the maintenance of internal

conditions within certain boundaries.



Ability to maintain a state of biological balance



Feedback systems monitor internal conditions and

make adjustments.

18 4. Living things respond to stimuli.

• Living things interact with the environment and

respond to changes in the environment.

(19)

(20)

Characteristics of Life

5. Living things reproduce and develop.

• All living organisms must reproduce

to maintain

a population.

• The manner of reproduction varies among

different organisms.

• When organisms reproduce, they pass on

copies of their genetic information (

genes

) to the

next generation.



Genes determine the characteristics of an organism.



Genes are composed of DNA (deoxyribonucleic acid).

(21)

Characteristics of Life

6. Living things have adaptations.

• An

adaptation

is any modification that makes

an organism better able to function in a

particular environment.

• The diversity of life exists because over long

periods of time, organisms respond to changing

environments by developing new adaptations.

• Evolution

is the change in a population of

organisms over time to become more suited to

the environment.

(22)

1.2 Evolution, the Unifying

Concept of Biology

• The theory of evolution explains the

diversity and unity of life.



The theory of evolution suggests how all living

things descended from a common ancestor.



Common descent with modification

(23)

Evolutionary Tree of Life

23 An evolutionary

tree is like a

family tree. An

evolutionary tree

traces the

ancestry of life on

Earth to a

(24)

common

ancestor

(first cells)

(25)

common

ancestor

(first cells)

BACTERIA

(26)

common

ancestor

(first cells)

BACTERIA

ARCHAEA

cell with nucleus

EUKARYA

(27)

common

ancestor

(first cells)

BACTERIA

ARCHAEA

Protists

cell with nucleus

EUKARYA

(28)

common

ancestor

(first cells)

BACTERIA

ARCHAEA

Protists

Plants

Fungi

Animals

cell with nucleus

EUKARYA

(29)

common

ancestor

(first cells)

BACTERIA

ARCHAEA

Protists

Plants

Fungi

Animals

Present

Time

Past

cell with nucleus

EUKARYA

(30)

Organizing Diversity

• Taxonomy

is the branch of biology that

identifies, names, and classifies

organisms.

• Systematics

is the study of evolutionary

relationships between organisms.

• Classification categories



From least inclusive category (species) to

most inclusive category (domain):

• Species, genus, family, order, class, phylum, kingdom,

and domain

(31)

(32)

Domains

• Domain Archaea



Contains unicellular prokaryotes that live in extreme

environments

• Prokaryotes

lack a membrane-bound nucleus.

• Domain Bacteria



Contains unicellular prokaryotes that live in all

environments

• Domain Eukarya



Contains unicellular and multicellular eukaryotes

(33)

Domain Archaea

33 Methanosarcina mazei

, an archaean

1.6 m

• Prokaryotic cells

of various shapes

• Adaptations to

extreme environments

• Absorb or

chemosynthesize food

• Unique chemical

characteristics

(34)

Domain Bacteria

34

• Prokaryotic cells

of various shapes

• Adaptations to

all environments

• Absorb, photosynthesize,

or chemosynthesize food

• Unique chemical

characteristics

Escherichia coli

, a bacterium

1.5 m

(35)

Fig. 1.8

Passiflora, passion flower, a flowering plant

Domain Eukarya: Protists

• Algae, protozoans, slime molds, and water molds • Complex single cell (sometimes filaments, colonies, or even multicellular)

• Absorb, photosynthesize, or ingest food

Paramecium, a unicellular protozoan

1 µm

Domain Eukarya: Kingdom Fungi

• Molds, mushrooms, yeasts, and ringworms

• Mostly multicellular filaments with specialized, complex cells • Absorb food

Amanita, a mushroom

Domain Eukarya: Kingdom Plantae

• Certain algae, mosses, ferns, conifers, and flowering plants • Multicellular, usually with specialized tissues, containing complex cells

Domain Eukarya: Kingdom Animalia

• Sponges, worms, insects, fishes, frogs, turtles, birds, and mammals • Multicellular with specialized tissues containing complex cells • Ingest food

Vulpes, a red fox

• Photosynthe size food

a: © Michael Abby/Visuals Unlimited; b: © Pat Pendarvis; c: © Tinke Hamming/Ingram Publishing RF; d: © Corbis RF

(36)

Kingdoms

• Domain Archaea

– kingdom designations

undetermined

• Domain Bacteria

- kingdom designations

undetermined

• Domain Eukarya



Protists (composed of several kingdoms)



Kingdom Fungi



Kingdom Plantae

(37)

Scientific Names

• Universal

• Latin-based

• Binomial nomenclature



Two-part name



First word is the genus.

• Always capitalized



Second word is the species designation (or specific

epithet).

• Written in lowercase



Both words are italicized.



Examples:

Homo sapiens

(humans),

Zea mays

(corn)

(38)

38 Natural Selection

• Evolutionary mechanism proposed by

Charles

Darwin

• Some aspect of the environment selects which

traits are more apt to be passed on to the next

generation.



Individuals with the favorable traits produce the

greater number of offspring that survive and

reproduce.



Increases the frequency of those traits in population

• Mutations fuel natural selection.

(39)

Some plants within a population exhibit variation in leaf structure.

Deer prefer a diet of smooth leaves over hairy leaves. Plants with hairy leaves reproduce more than other plants in the population.

(40)

1.3 How the Biosphere Is

Organized

• The

biosphere

is the zone of air, land, and

water where organisms exist.

• A

population

is all the members of a

species within an area.

• A

community

is a collection of interacting

populations within the same environment.

• An

ecosystem

is community plus its

physical environment.

(41)

Ecosystems

• Ecosystems are characterized by chemical

cycling and energy flow.



Chemicals are not used up when organisms

die.

• Chemicals move from one population to another in a

food chain.

• As a result of death and decomposition, chemicals

are returned to living plants.



Energy from the sun flows through plants and

other members of the food chain as one

population feeds on another.

• Therefore, there must be a constant input of solar

energy.

(42)

WASTE MATERIAL, DEATH, AND DECOMPOSITION

heat

heat heat

solar

energy

Chemical cycling Energy flow

heat

(43)

The Human Population

• Ecosystems have been negatively impacted

by human populations.



Destruction of forest or grassland for

agriculture, housing, industry



Destruction of coastal wetlands by waste and

other pollutants

• Humans depend upon healthy ecosystems

for:



Food



Medicines

(44)

The Effect of Human Activities

on Coral Reefs

44 1975 Minimal coral death

b.

a. Healthy coral reef

1985 Some coral death

With no fish present

1995 Coral bleaching with

limited chance of recovery

2004 Coral is black from

sedimentation; bleaching

still evident

(45)

Biodiversity

• Biodiversity

is the total number and relative

abundance of species, the variability of their

genes, and the ecosystems in which they

live.



Estimated to be as high as 15 million species

• Less than 2 million have been named and identified

• Extinction

is the death of the last member

of a species or larger classification category.



Estimates of 400 species/day lost due to human

(46)

1.4 The Process of Science

• The

scientific method

is a standard series

of steps used in gaining new knowledge

through research.



The scientific method can be divided into four

steps:

• Observation

• Hypothesis

• Experiments and Data Collection

• Conclusion

(47)

The Scientific Method

1. Observation

• Scientists use their senses to gather

information about a

phenomenon

or natural

event.

2. Hypothesis

• A

hypothesis

is a tentative explanation for

what was observed.

• Developed through inductive reasoning

• Testable

(48)

The Scientific Method

3. Experiments and Data Collection

• An

experiment

is a series of procedures

designed to test a hypothesis.



Utilizes deductive reasoning to make a

prediction

or expected outcome

• The manner in which a scientist conducts an

experiment is called the

experimental

design

.



A good experimental design ensures that the

scientist is examining the contribution of a specific

factor called the

experimental (independent)

variable

to the observation.

• The experimental variable is the factor being tested.

(49)

The Scientific Method

3. Experiments and Data Collection (cont’d)

• A

test group

is exposed to the experimental

variable.

• A

control group

goes through all aspects of

the experiment but is not exposed to the

experimental variable.

• The

data

are the results of an experiment.



Should be observable and objective

(50)

The Scientific Method

4. Conclusion

• The data are analyzed and interpreted to

determine whether the hypothesis is

supported or not.



If prediction happens, hypothesis is supported.



If not, hypothesis is rejected.

• Findings are reported in scientific journals

• Peers review the findings

• Other scientists then attempt to duplicate or

dismiss the published findings

(51)

Observation

New observations

are made, and previous

data are studied.

(52)

Observation

New observations

are made, and previous

data are studied.

Hypothesis

Input from various sources

is used to formulate a

testable statement.

(53)

Observation

New observations

are made, and previous

data are studied.

Hypothesis

Input from various sources

is used to formulate a

testable statement.

Experiment/Observations

The hypothesis is

tested by experiment

or further observations.

(54)

Observation

New observations

are made, and previous

data are studied.

Hypothesis

Input from various sources

is used to formulate a

testable statement.

Conclusion

The results are analyzed,

and the hypothesis is

supported or rejected.

Experiment/Observations

The hypothesis is

tested by experiment

or further observations.

(55)

Observation

New observations

are made, and previous

data are studied.

Hypothesis

Input from various sources

is used to formulate a

testable statement.

Conclusion

The results are analyzed,

and the hypothesis is

supported or rejected.

Scientific Theory

Many experiments and

observations support a

theory.

Experiment/Observations

The hypothesis is

tested by experiment

or further observations.

(56)

Observation

New observations

are made, and previous

data are studied.

Hypothesis

Input from various sources

is used to formulate a

testable statement.

Conclusion

The results are analyzed,

and the hypothesis is

supported or rejected.

Scientific Theory

Many experiments and

observations support a

theory.

Experiment/Observations

The hypothesis is

tested by experiment

or further observations.

(57)

Scientific Theory

• Scientific Theory:



Concepts that join together two or more well-supported

and related hypotheses



Supported by broad range of observations, experiments,

and data

• Scientific Principle / Law:



Widely accepted set of theories



No serious challenges to validity

(58)

58

(59)

= Pigeon pea/winter wheat rotation

15 20

10

5

0

year 1 year 2 year 3

= no fertilization treatment = 45 kg of nitrogen/ha Control Pots

Test Pots

= 90 kg of nitrogen/ha

Wh e a t Biom a s s (gra m s /p ot) b. Results a. Control pots and test pots

of three types

Test pots

90 kg of nitrogen/ha

Test pots

Pigeon pea/winter wheat rotation

Control pots

no fertilization treatment

Test pots

45 kg of nitrogen/ha

(All): Courtesy Jim Bidlack

Using the Scientific

(60)

a. Scientist making observations

b. Normal mountain bluebird nesting behavior

c. Resident male attacking a male model near nest

resident male female mate male bluebird model

d. Observation of two experimental nests provided data for graph. 1.5 2.0 1.0 0.5 0 A pproac hes per M inute nest construction first egg laid hatching of eggs Stage of Nesting Cycle

Approaches to male model Approaches to female mate nest 2 nest 1