Transcript Ch 1-3 Envir

Chapter 1
Populations & Communities
Section 3
Interactions Among Living Things
Notes 1-3
Adapting to Environment
Natural Selection
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Process that changes an organism to better
suit their environment
Those organisms with characteristics best
suited for their environment will be successful
Those poorly suited for their environment are
less likely to reproduce or survive
Over time poorly suited characteristics disappear
from the population
Adapting to Environment
Adaptations
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Behaviors and physical characteristics that
allow the organism to be successful in the
environment
Every organism has some kind of adaptation
Niche
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The role the organism plays in its environment
Its job…how it lives
Food, how it gets food, what other organisms use it
for food
Interactions Among Organisms
Competition
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The struggle between different organisms to
survive in a habitat with limited resources
There is a limited amount of food, water, and
shelter
Those organisms that survive find a way to
reduce competition
Finding a way to all use the same area for food
Using chemicals to get rid of competition
Interactions Among Organisms
Predation
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One organism kills and eats another organism
Predator:
Organism that does the killing
Adapt to become faster, develop a poison or lure
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Prey:
Organism that is killed
Adapt to become by using camouflage, warning
colors and mimicry (See page 34 & 35)
Interactions Among Organisms
Predation and Population Size
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See graph on page 36
As the wolf population increases, the moose
population decreases
Wolf eats too many moose
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Then the wolf pop. decreases and the moose
pop. increases again
Wolf die off because there isn’t enough food and
then the moose start to rebound
Symbiosis
Close relationship between two species
that benefits at least one of the species
Mutualism
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Both species benefit
Bacteria in your large intestine receive food
and shelter and you get nutrients from food
that the bacteria break down for you
Symbiosis
Commensalism
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One species benefits and the other isn’t
helped or destroyed
Doesn’t happen often in nature
Red tailed hawk interacting with the saquaro
cactus
Hawk has shelter but cactus isn’t affected
Symbiosis
Parasitism
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One organism lives in or on another organism
and harms it
Parasite:
Organism that benefits
Usually small
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Host:
Organism that is harmed
Usually bigger than parasite
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Leeches on your body
Won’t usually kill the host, because it won’t
have food or shelter anymore
Homework
Key Terms
Ch. 1
Due: Friday