Some definitions…
●
Biological Community = All of the
populations in an area.
●
Population = groups of organisms of a
single species.
●
Species = share similar characteristics.
Populations
●
POPULATIONS -
●
Populations of living things increase and decrease in
size as they interact with other populations and with
the environment.
●
There are 3 important characteristics of a
population:
Geographic distribution: the area (range) inhabited by the
population
Density: number of individuals per unit area
Growth Rate: depends on birth rate, death rate, and
Influences that affect
Population Growth
●
Limiting Factor: a factor that causes
population growth to decrease
●
Two Types =
1.) Density-dependent limiting factors: these factors only become limiting when the population reaches a certain level
Examples: competition, predation, parasitism, and disease, food supply, stress
2.) Density-independent limiting factors: these factors affect all populations, regardless of size
Density-independent vs.
Density dependent factors…
A Population Activity…
http://video.nationalgeographic.com/video/kids/animals-pets-kids/mammals-kids/raccoon-kids/
Objective: To recognize major components of an animal’s habitat and to understand limiting factors and how they effect populations.
Main Ideas:
• Many factors affect the ability of wildlife to survive over time: Examples?
•Weather, disease, predators, pollution, habitat destruction, hunting, and resource
availability.
• Habitat / Living conditions are the key to survival and population size. • Today’s “habitat” is defined as the types of food and water available.
Gangster Birds
NOVA (11:30)
●
http://www.pbs.org/wgbh/nova/scienceno
Population Growth
● Natality = birth rate ● Mortality = death rate
● If Natality = Mortality … stable population (not necessarily healthy
ex. Ethiopia)
Answer these by labeling (1,2,3) on the graph
1. Where is Natality = Mortality?
2. Where is Natality greater than Mortality?
Exponential Growth
Logistic Growth
Carrying Capacity
Population Spikes
Population Dips
Max. load of Population
Carrying Capacity: the largest number of individuals that a
Graphing changes in population
growth
*** Do this on separate sheet
(Graphing Practice worksheet)
● Using this table, plot the population growth of bacteria over one day.
● Time # of Bacteria
● Beginning 1
● 20 min. 2
● 40 min. 4
● 60 min. 8
● 80 min. 16
● 100 min. 32
● 120 (2 hrs.) 64
Human Population Growth
● The size of the human population tends to increase with
time.
● To predict how the world population will grow,
demography must consider many factors including the
Age Structure =
Human Population Growth
●
Look at the following graphs to answer the
questions
:
● Has there ever been a year where the world population declined?
When? Cause?
● Which of the last 100 years had the highest growth rate?
● What do you notice about the annual average growth rate from
1962 to today? Does that trend continue?
● Do you think the world population growth rate will ever be 0% or
negative? Why?
● At what point in time did the human population begin to grow
Factors that Affect Ecosystems…
● abiotic environment is the physical, or non-living part of the
environment.
● Abiotic factors in the environment
The ability of an organism to live and reproduce depends on certain physical and chemical abiotic factors in its environment.
● Abiotic Factors include:
Intensity of light, temp range, amount of moisture, type of soil or rock
Limiting factors (nothing to write here
● In any particular environment, each of the abiotic factors varies over a certain
range.
This range sets limits on the types and
numbers of organisms that can live in that environment.
For example, in a desert, the small amount
of moisture available is a limiting factor that
determines which plants and animals can survive there.
Other examples:
● Low temperature of regions at high altitudes,
Factors that Affect Ecosystems, contd…
●
Biotic environment
is the
living
part of the
environment.
●
It includes all the
interacting populations
of
living
Biotic Factors
● The living things of the ecosystem act as biotic factors in
the ecosystem.
● The biotic factors affect both the living and the non-living
parts of the environment. They include not only the living organisms, but their parts, interactions, and waste
Effects
of
Biotic Factors
in the
Environment:
● Autotrophs: produce organic nutrients containing stored
chemical energy. Bacteria of decay (decomposers) return materials to the
physical environment for reuse.
● The consuming of one organism by another transfers
energy within the ecosystem.
● The branches and leaves of large trees
limit the kinds of smaller plants that can live in the shade they produce.
WAYS ORGANISMS INTERACT
http://www.epa.gov/region5/superfund/ecology/images/fishcartoon.gif
http://www.uark.edu/depts/agripub/Publications/Agnews/mosquito.jpg
●
http://www.youtube.com/watch?v=iyCZqkX-f_
8
●
http://www.youtube.com/watch?v=TGRuen6B
3 Types of Interactions
● 1. Competition: occurs when organisms of the same or
different species attempt to use an ecological resource in the same place at the same time.
● 2. Predation: an interaction in which one organism
captures and feeds on another organism.
● 3. Symbiosis: a relationship in which 2
WAYS ORGANISMS INTERACT #1
COMPETITION
FOOD
Organisms in an ecosystem have to
compete with each other for available
resources.A)
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: B)
http://www.dpiw.tas.gov.au/inter.nsf/Images/LBUN-5K538R/$File/fox_adultandcub.jpg http://www.gdccc.org/Records/EOY2004/NSEOY.htm
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
Resources C)
mates
http://www.wasatchcomputers.net/gallery/elk_fight.jpg
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: D)
space/territory
http://www.rilanationalpark.org/gr.phtml?dir=../../pictures/in_text&img=/65_1180.jpg http://www.elise.com/weblog/photos/prairie-dogs.jpg
Prairie dogs - 5 to 35 per acre
COMPETITION
Organisms in an ecosystem have to
compete with each other for available
resources: E)
LIGHT
http://vilenski.org/science/safari/cellstructure/chloroplasts.html
VS.
INTRASPECIES COMPETITION
●
Intra = two organisms within the
same species
RABBIT SQUIRREL VS.
INTERSPECIES COMPETITION
●
Inter =Two organisms from
Ways organisms interact #2
___________________
Between DIFFERENT kinds of organisms
Hunt and kill other organisms to supply
their energy needs
PREDATION
PREDATION
Organisms in an ecosystem that capture and
eat other organisms to supply their energy
needs
http://personal.ecu.edu/wuenschk/rabbit-wolf.gif
Predator-Prey Relationships
1. Predators
• Control herbivores by weeding out the old or weak …
healthier population
• Without the predation numbers go out of control • Ex. Zebra mussels
• Ex. Moose on Isle Royal 25 wolves 400 moose • Deer left unchecked – overgraze, crop damage,
REMEMBER: EVERYTHING IS CONNECTED !
A decrease in the prey population means some predators will starve. Fewer predators mean prey population will increase.
Increase in prey means more food for predators.
Predator population will increase until there is not enough food . . . and the cycle repeats itself.
Ways organisms interact #3
__________________________
Between
DIFFERENT
kinds of organisms
Live in close association with another kind
of organism
SYMBIOSIS
3 KINDS of SYMBIOSIS
______________________
Both organisms benefit
______________________
One organism benefits;
Other is neither harmed nor helped
_____________________
One organism benefits;
Other is harmed in some way
MUTUALISM
COMMENSALISM
#1: MUTUALISM
Example
“Good for me - Good for you”
Birds eat parasites living
on the hides of giraffes and
rhinos while enjoying
protection from predators
.
Groomed animals lose their
pests.
Another MUTUALISM
example
“Good for me - Good for you”
Insects transfer pollen
between plants as they
gather nectar for food
.http://www.yksd.com/DistanceEdCourses/YKSDbiology/lessons/SecondQuarterLessons/Chapter5/5-5/images/3-way-mutualism.jpg
Another MUTUALISM
example
“Good for me - Good for you”
Clown fish gets protection from enemies by
hiding out in poisonous sea anemones
http://www.zahnersatz.com/english/library/symbiosis.jpg
Sea anemone gets
scraps of leftover
food dropped
#2: COMMENSALISM
“Good for me - Doesn’t bother you”
http://www.geology.wmich.edu/gillespie/g322/Chapters/C16shark.gif
Pilot fish receive scraps of food dropped by
shark;
Another COMMENSALISM example
“Good for me - Doesn’t bother you”
http://www.abyssal.com/meeks/images/hermit_crab.jpg
#3: PARASITISM
“Good for me - Hurts you”
Barnacles are crustaceans that attach to the surface of whales and feed on their skin and fluids; Whale is harmed
Another PARASITISM example
“Good for me - Hurts you”
Tick feeds on dog’s blood;
Another PARASITISM example
“Good for me - Hurts you”
Tapeworms absorb
food by living inside
host intestine;
host is harmed
More Parasitism examples
Athletes foot fungus in humans-The fungus obtains nutrition from the skin, but causes itchy scales and swellings
Human Impact
Human Impact
● Humans can have a tremendous impact on the
The Greenhouse Effect
● Greenhouse Effect- When carbon dioxide, methane,
water vapor and a few other atmospheric gases trap heat energy and maintain Earth's temperature range.
● Causes: One of the biggest causes is the production of
CFC’s (Chlorofluorocarbons) They are used as a
Human Impact continued…
●
Global Warming -
An increase in the earth's average atmospheric temperature that
causes corresponding changes in climate and that may result from the greenhouse effect.
●
Consequences:
Average U.S. temperatures could rise another 3 to 9 degrees by
the end of the century.
Sea levels will rise, flooding coastal areas.
Heat waves will be more frequent and more intense. Droughts and wildfires will occur more often.
