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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