BIOL 301: Resource Partitioning
42 Cards in this Set
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Species coexistence may depend on...
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how the species divide resources
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How does a narrow resource spectrum control species richness?
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Species in this community show a high degree of specialization, with little overlap, in their resource use.
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How does a broad resource spectrum result in higher species richness?
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Resource spectrum is broad, making more kinds of resources available to support more species.
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What are 4 ways to describe species interactions?
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1. Competition
2. Consumption
3. Commensalism
4. Mutualism
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Define competition.
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An interaction between species (or individuals) that has a negative impact on both species (or both individuals).
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Impacts of competition include:
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1. Decreasing population size
2. Decreasing biomass
3. Decreasing growth rate
4. Decreasing reproduction
5. Increasing mortality
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When does competition occur?
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Competition occurs when organisms are using the same resource and demand exceeds supply.
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Different types of competition include:
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1. Intraspecific competition
2. Interspecific competition
3. Exploitation competition
4. Interference competition
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Describe intraspecific competition.
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Competition between individual members of the a same species.
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Describe interspecific competition.
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Competition between individual members of different species.
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Describe exploitation competition.
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Competition where individuals affect resource abundance but do not directly interaction with competition.
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Describe interference competition.
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Competition in which individuals have negative impacts on competition (e.g. territoriality and fighting).
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What do plants compete for?
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1. Sunlight
2. Water
3. Inorganic nutrients (N and P)
4. Pollinators
5. Seed dispersal
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What do animals compete for?
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1. Food
2. Shelter
3. Space
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Why is competition important?
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Intraspecific competition will control population size, if something else does not.
Interspecific competition is an important factor in determining the distribution, abundance, behavior, diet, etc...of organisms.
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How do competitive interactions impact the organismal richness?
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Resource utilization impacts the number of species in a community
Realized niche versus fundamental niche
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What is the competitive exclusion principal?
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States that it is not possible for species with the same niche to coexist.
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When does the competitive exclusion principal occur?
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Occurs when competition is asymmetrical because, if two species have completely overlapping niches, there is not refuge for the weaker competition. The weaker competition may be driven to extinction.
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What is niche differentiation?
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Describes a way that selective pressures due to competitive interactions can result in coexistence of species in communities.
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When does niche differentiation occur?
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When two species have a partially overlapping niche, one species may shift their niche to avoid overlap.
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Define consumption.
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Occurs when one organism eats or absorbs nutrients from another
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How does consumption affect fitness?
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Consumption interaction increases the consumer's fitness but decreases the victim's fitness.
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What are 3 different types of consumption interactions?
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1. Herbivory
2. Parasitism
3. Predation
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When does herbivory consumption take place?
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Takes place when herbivores consume plant tissue.
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When does parasitism take place?
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Takes place when organisms derive benefit from a relationship that harms a host organism.
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What is a host organism?
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An individual that the parasite lives on or in.
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What are 3 types of parasites?
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1. Biotrophic parasites
2. Necrotrophic parasites
3. Parasitoids
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What is a biotrophic parasites? Give examples.
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A biotrophic parasite only thrive if host is living.
Examples include: fleas, lice, intestinal worms
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What are necrotrophic parasites? Give examples.
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Necrotrophic parasites may kill the host but would feed on decaying corpse.
Examples include: blowflies
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What are parasitoids?
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Parasitoids are parasites that always kill the host. Many lay their eggs in the larvae of other insects.
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When does predation occur?
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Predation occurs when a predator kills and consumes all or most of another individual.
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How is predation a directional interaction?
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Benefits and consequences to the predator and prey involved are not equal. The impact is more severe on the prey because they die.
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What are two components of the predation theory?
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1. Predator-prey cycles
2. Foraging ecology
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What are scientists interested in when studying predator-prey cycles?
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Interested in the response of predator populations to changes in the abundance of prey.
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How are relationship between predator and prey complex?
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Prey defensive ability is under stronger selective pressure than predator offensive behavior.
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Give examples of prey defensive abilities.
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1. Alarm calls
2. Cryptic coloration (camouflage)
3. Mimicry
4. Aposematic coloration (warning coloration)
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What are scientists interested in when studying foraging ecology?
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Interested in how predators select their prey.
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What questions do foraging ecologists try to answer?
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1. What kind of prey should a predator eat?
2. What size prey should be consumed?
3. What kind of behavior do you use to find, subdue, and swallow that prey item?
4. When and how often do you forage?
5. Where do you forage?
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What is commensalism?
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An interaction between two species where one species derives a benefit from the relationship while the other species is unaffected by the relationship.
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What is mutualism?
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An interaction between two species in which both species benefit.
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Explain the mutualist relationship between salamanders and temporary ponds.
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Spotted salamanders lay eggs in fishless temporary ponds. If the pond suddenly turns green, they have a mutualistic relationship with algae in their cells. Algae helps to keep oxygen supply from depleting.
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What are the two main outcomes of species interactions?
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They affect the distribution and abundance of the interacting species
They are potential agents of natural selection and as such could affect the evolution of the interacting species
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