What is the difference between a population and a ...

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Community Ecology

What is the difference between

a population and a community?

Each species has a niche in the community

• If a species is naturally found in a specific area or habitat,

it is because it is adapted to it

• The individuals of this species are adapted to

the abiotic (climate) and

biotic factors (community) of this area.

• Each species has specific niche (a place in the community):

resources it uses (food or shelter)

role in the community (interactions with others)

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Interspecific interactions in the community

Competition

Predation

Symbiosis

Competition relationship:

When two or more species compete for the same resource

(when species have a similar niche)

How do two competitors solve competition?

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When two species compete it can result in:

competitive exclusion or resource partitioning

competition leads to elimination of

one of the species from the area competition drives a species

to differ by one or more factors

Predation Relationship:

Interaction where

the consumer is the predator

and the food species is the prey

How does predation affect the prey population?

In the predator species, what traits will evolution select for?

In the prey species, what traits will evolution select for?

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Prey Adaptations Plant’s defenses:

can be Mechanical or Chemical

Animal’s defenses

warning coloration

cryptic coloration

mimicry

Prey adaptations

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Predators adaptations to ambush or to pursuit Predator Adaptations

Identify the adaptation!

Coyote and horned lizard

Sargassum fish

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Symbiotic Relationships

An interaction in which two species live in close physical contact

Types of symbiosis depending on benefits-harm:

Parasitism

Mutualism

Commensalism

Parasitism The parasite lives in or on the host

Parasite benefits and host is harmed

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Commensalism The commensalist gets a benefit

and the host is not harmed or benefited

Mutualism

Both organisms get a benefit

• EXAMPLES:

bean plants and bacteria

lichens

corals

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Identify the type of symbiosis

Snails and worms

Thorn trees and ants

Can humans benefit

from some of these interactions?

when the human is not one of the

species in the relationship

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Humans have been able to use these

relationships for their own benefit

Use of chemical defenses against predation:

10 of top 25 drugs come directly from wild plants

the rest were developed by studying plants

Use of predation or parasitism:

As natural control of undesired

Organisms (pests)

Use of a mutualistic relationship:

As natural fertilizer

Can humans harm

interactions in a community?

Introducing new species in the community

Removing species from the community

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Part III - "Why Are Killer Whales Eating Sea Otters Now?"

• Develop hypothesis

When the great whales were abundant,

their biomass may have been 60 times the

combined biomass of all of the seals, sea

lions, and sea otters.

The great whales would have been able to

sustain vastly more killer whales than could

populations of sea lions and sea otters

Why are killer whales eating sea otters now?

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Part IV. Who cares if otter numbers are decreasing?

Decreases diversity

leads to deforestation

Predator removal can harm the environment

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What can happen when humans

(intentionally or unintentionally)

introduce a foreign species to a community?

Invasive or Introduced species

Case 1: Feral and Out door pet cats

About 100 million cats

between 1.4 and 3.7 billion birds killed

Case 2: Argentine ants

US spends $137 billion spent each year for

ALL invasive species.