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Study Questions: Populations, Communities Species Interaction

1. Define the terms herbivore, carnivore and omnivore; explain the terms primary vs. secondary produces, giving examples of each.

2. Define the term species and explain what determines where a species lives.

3. Explain evolution, using terms such as adaptation, natural selection, selective pressure and mutation.

4. How and why might new species come into being?

5. Compare and contrast predation, parasitism, competition, and symbiosis (including mutualism and commensalism)

6. Discuss ideal vs. actual population growth; compare and contrastr- and k-reproductive strategies.

7. Describe and define a community, including diversity and abundance, and succession.

Populations, Communities and Species Interaction

Ecology: study of relationships

betweens organisms and

their environment

Ecosystem: biological community

and its environment

Herbivore:

Carnivore:

Omnivore:

organism that eats plant matter

organism that eats animal matter

organism that eats plant and animal matter

Primary producers: organisms that do photosynthesis

6H2O + 6CO2 + sunlight C6H12O6 (sugar) + 6O2

Pix of plant, algae

Consumers: organisms that do not do photosynthesis, but obtain their nutrients by eating

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Food Chains and Food Webs: interactions and connections between organisms that transfer organic matter via eating

Trophic level: an organism’s feeding status; its place in the food chain

Species: genetically similar organisms that can successfully reproduce with each other

What Determines Where Species Live?

Factors such as temperature, nutrient supply, etc.

Tolerance limits: minimum and maximum levels of factors beyond which organisms cannot survive

Popu

latio

n si

ze

Low High Temperature

Zone ofintolerance

Zone ofphysiological stress

Optimum range Zone ofphysiological stress

Zone ofintolerance

Noorganisms

Feworganisms

Lower limitof tolerance

Abundance of organismsFew

organismsNo

organisms

Upper limitof tolerance

Range of Tolerance

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Adaptation: changes that allow an organism or population to survive in its environment

Some of these changes are passed on genetically

Evolution: gradual changes in species that result from competition for scarce resources

Selective pressures and random mutations lead to

Natural selection: the process in which better competitors reproduce more successfully

Speciation: the development of a new, distinct species

Speciation can occur as a result of:

• New food or other resource

• New stress (climate or predator)

• Geographic isolation

• Behavioral isolation

4 of the 13 Galapagos Finch Varieties

Species Interactions

• Predation

Predator: organism that feeds directly upon another living organism (prey)

Predator can affect population of preyScorpion Fish

American bittern

Co-evolution: predator and prey evolve in response to each other (camouflage, mimicry)

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Monarch Viceroy

Longhorn Beetle

• Competition

Organisms compete for:

Nutrients, space, mates, etc.

Intra- and inter-specific competition exist

• Symbiosis: 2 or more species living together

Commensalism: 1 species benefits, 1 is neutral

Mutualism: both members benefit

Parasitism: 1 species benefits, 1 is harmed Population DynamicsPopulation: all members of a species that live in the

same area at the same time

Population growth depends on many factors

• Size of population

• Resource availability

• Predator populations

• Environmental conditions

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Ideal, unlimited population growth is exponential

Actual growth slows down as resources become limited

J curve S curve

Reproductive Strategies

r-adapted species: use rapid, copious reproduction

K-adapted species: slower reproduction, fewer offspring

CommunitiesCommunity: all the populations that live and interact in an area

Ecotones: boundaries between adjacent communities

Diversity: number of different species within an area

Abundance: number of individuals of a species within an area

The greater diversity in a community, the greater resiliency and stability of that community

Primary succession: development of a community where none has previously existed

Secondary succession: development of a community where a pre-existing community was disrupted or destroyed

Climax community: stable community with no further succession; “mature” community

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Invasive species: organisms not normally found in a particular location that disrupt the local community

Hawaiian mongoose Polynesian rat