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BIOLOGY NOTES – 7A ECOLOGY BASICS
Levels of Ecological Organization

Habitat vs Niche
o Habitat

____________________ an organism lives
o NICHE

What an organism ____________________
and how it ____________________ with the
environment
o ____________________
____________________
Principle

No two species can occupy the exact same
____________________

____________________ - Sharing resources
BIOLOGY NOTES – 7A ECOLOGY BASICS
Biotic vs Abiotic Factors

____________________ Factors
o Relationships between ____________________ organisms


Humans pick flowers

Coyotes eat chickens
____________________ Factors
o ____________________ or ____________________ factors that affect living organisms


____________________________________________________________
BIOTIC FACTORS
o Competition

____________________ for resources

________________________________________
o Predation

One organism ____________________ and
____________________ the other

____________________ – herbivores eating plants


Similar to predation
____________________ – mimic a dangerous animal so that others stay away
o Parasitism

One organism ____________________ on another (typically does not
kill the host)
o Mutualism

____________________ organisms benefit
o Commensalism

One organism benefits and the other is
________________________________________
o Disease

Spread of ____________________ or disease causing
agents

____________________ or ____________________
BIOLOGY NOTES – 7A ECOLOGY BASICS

____________________ FACTORS
o ____________________
o ____________________
o ____________________
o ____________________
o ____________________
o ____________________
Populations

Both biotic and abiotic factors can affect ____________________ ____________________

Population size =

(+) Number of ____________________

(-) Number of ____________________

Number of organisms that (+) move in (____________________) or (-) out
(____________________) of a population

Exponential Growth

Population under ____________________ conditions with ____________________ resources
can grow ____________________


____________________ Shaped graph
In the real world…

Most population do ____________________ have unlimited resources

Biotic factors: ____________________________________________________________

Abiotic Factors: ____________________________________________________________

All affect the growth of a population
BIOLOGY NOTES – 7A ECOLOGY BASICS

Logistic Growth

Populations may experience growth, but eventually reach ______________________________

Carrying Capacity


Limiting Factor


Anything that can ____________________ population size
Density ____________________ Limiting Factors


Maximum number of individuals a particular environment can support at a given time
Any limiting factor that affects dense populations ____________________

____________________

____________________

____________________
Density ____________________ Limiting Factor

Any limiting factor that affects all population equally

____________________

____________________

____________________

____________________
BIOLOGY NOTES – 7A ECOLOGY BASICS


Non-Native Species

____________________Species

____________________
Stability

For the most part, ecosystems are relatively stable

Most population sizes remain relatively the same over time

Only when there are changes to the ecosystem does the population sizes change

If a small change occurs in an ecosystem, the population may change ____________________

If a dramatic change occurs in an ecosystem, the population size may change
____________________
BIOLOGY NOTES – 7A ECOLOGY BASICS
Vocabulary

Population – group of individuals of the same species living at the same place at the same time

Community – all of the different populations living in the same place at the same time

Ecosystem – all the communities that live in an area along with the nonliving environment
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Biosphere – the entire range in which living organisms live on Earth
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Habitat – where an organism lives
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Niche – the job that an organism performs in that habitat
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Competitive exclusion principle – no two species can occupy the same niche at the same time

Resource partitioning – the sharing of resources among organisms that would typical occupy the same
niche but instead have willingly partitioned themselves into smaller niches

Biotic – living things

Abiotic – nonliving things

Exponential – unlimited growth made possible only in the presence of unlimited resources

Logistic – growth that can only continue to the environment’s carrying capacity
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Carrying Capacity – the maximum number of organisms an environment can support at any given time

Non-native (Invasive) Species – species that are not originally present in an area but instead have been
introduced to an area artificially by human actions