Transcript Animal Populations

Animal
Population
Diversity and Structure
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Species diversity – number of different species a
community contains combined with the abundance
of individuals within those species.
Community niche structure – how ecological
niches vary and differ.
Niche – a species role in the community
Most diverse or species rich environments are the
tropical rain forests and some coral reefs.
Species types
Native Species – normally live in and thrive
in a particularly area
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Nonnative Species – accidentally or
deliberately introduced to an area
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White Tailed Deer, Bald Eagle, Opossum
Horses
Invasive Species/Alien Species – wreak
havoc on the environment. No natural
predators
Invasive Species
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Asian Carp
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Mississippi River
No natural predators
Eats all the plankton
Kudzu Vine
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South United States
7 million acres
Grows 1 ft per day
Kudzu bug (also invasive) started eating all of the
soybean crop.
4. Indicator Species – a species that serves as
early warnings of danger to an area
Ex – Butterflies, trout, frogs
ButterfliesThey have brief life cycles and are affected by
climate change and pesticides. Birds plan their
breeding season around when the caterpillers
are most abundant
TroutHealthy stream=abundant trout
They need clean water, a specific temperature,
protection, unsilted gravel to spawn and an
abundant food supply.
Indicator Species
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What about the frogs? Well…
Vulnerable because different life cycles
involve different habitats
Tadpoles – live in water and eat plants
Adults – live on land and eat insects that can
be exposed to pesticides
Eggs – have no protective shell so are
vulnerable to increased UV rays or pollution
Hundreds of species have vanished since 1980
 ¼ of all amphibian species are extinct,
endangered or vulnerable
Why should we care?
 Their death indicates that there is some
deterioration of the environment
 Large part of the ecological pyramid – they are
predator and prey
 Secretions in the skin - Can be used in the
pharmaceutical industry for medication
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5. Keystone Species – species that have a
significant role in the community
Examples:
A.Pollinators such as bees, humming birds, bats
B. Top predators such as wolves, lions,
alligators, and sharks
C. Decomposers such as beetles
 A loss of these types of species leads to
population crashes and extinctions
6. Foundation species – species that shape
communities by creating and enhancing their
habitats in ways that benefit others
Ex – Elephants, beavers
Energy in an Ecosystem
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Energy is the most important
factor in determining how many
and what kinds of organisms live
in an ecosystem.
Trophic Levels
1st Level
 Producers: take in
energy from their
surroundings and store
it in complex molecules.
 Also called
autotrophs/
photosynthetic
 Use the sun to power
the production of
food.
2nd Level
 Primary Consumers
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Obtain energy by consuming Autotrophs.
Also called heterotrophs.
3rd Level
 Secondary consumers
 Obtain energy by consuming both producers
and primary consumers
Tertiary Level
 Apex predators
 Top of the food chain
 Will consume anything from all of the
previous levels
Decomposers
 Consumers that obtain energy by consuming
organic wastes (feces, urine, leaves, dead
plants) and dead bodies.
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Recyclers of nutrients.
Food Chain
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Single pathway of feeding relationships among
organisms in an ecosystem that results in
energy transfer.
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Example:
grass 
mice 
snake 
hawk
Food Web
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Multiple food chains in a ecosystem
Many consumers eat more than one kind of food.
More than one species may eat the same organism.
Species interaction
5 Basic types of interaction
1. Interspecific competition – competition between
species for shared resources such as space and food
2. Predation – one species (predator) directly feeds on
another (prey)
Ex – lions eat gazelle
3. Parasitism - when one species (parasite) feeds on
part of another organism (host)
Ex – Ticks, Tapeworm
4. Mutualism – two species interact in a way that
benefits both.
Ex – Oxpeckers and Rhinos
Clown fish and sea anemones
5. Commensalism – one species benefits and the
other is not effected
Ex – Epiphytes and tropical trees
Remora Fish and the Shark
Avoiding Predation
1. Camouflage – uses shape or color to hide
2. Chemical warfare – examples are poisons,
irritants (stingers), Foul smells (skunk), tasting
bad (monarch butterfly)
3. Warning colors – bright colors indicate an
organism is poisonous
4. Mimicry – looking and acting like another
animal
Limits on Population Growth
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Environmental resistance – factors that act to limit the
growth of a population
Examples:
disease, predators, natural events, humans
Logistic growth – involves exponential growth followed
by a steady decrease in population growth with time until
the population size levels off.
Human Impacts
We Have:
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Reduced biodiversity
Used, wasted, or destroyed net primary productivity
that supports all consumers
Strengthened some populations of pests and bacteria
Eliminated some predators
Introduced nonnative species in communities
Interfere with chemical cycles and energy flow