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104 Cards in this Set
- Front
- Back
What happened in G. Tansley's competition experiment?
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-included two species of bedstraw, G. saxatile and G. sylvestre that were put into acidic and calcareous soils -G. saxatile grew best in acidic soil -G. sylvestre grew best in calcareous soil -when placed together, each grew, but there were more of the bedstraw that favored that particular soil. |
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define competition.
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an interaction between individuals in which each is harmed by their shared use of a limiting resource
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what type of interaction is competition?
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-/-
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is competition always -/-?
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yes, because no matter who wins, they had to give up something like energy.
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Give another name for fundamental niche and define it.
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pre-interactive nich -where a species can be found |
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give another name for realized niche and define it.
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post-interactive niche -where the species is actually found |
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Define interspecific competition.
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this is the interaction between two species in which each is harmed when they both use the same limiting resource
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Define intraspecific competition.
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same as intraspecific competition, but an interaction between individuals of a single species -could be between/over mates, with a population, or between populations |
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Which type of competition should be more intense? Intraspecific or Interspecific?Why?
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Intraspecific competition will usually be more intense because they are within the same species and will have the same resource demands. Interspecific competition is usually less intense, as different species will have somewhat different requirements, allowing for some resources to not be contested.
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define resources.
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these are features of the environment required for growth, survival, or reproduction that can be consumed to the point of depletion
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What happened in the experiments with the Diatoms (synedra and asterionella)?
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-when each species was grown alone, a stable population size was reached -When grown together, they competed for silica, and one species drove the other to extinction |
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Who wins in the diatom competition experiment?
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the species that could survive at the lowest level of the shared resource
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define exploitation competition.
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species compete indirectly -individuals reduce the availability of a resource as they use it; now others can't use it because it's already been exploited |
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define interference competition.
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species compete directly for access to a resource
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define competitive exclusion principle.
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two species that use a limiting resource in the same way cannot coexist for long periods of generational times
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How similar do two niches have to be before competitive exclusion applies?
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there is NO coexistence if there is lots of niche overlap d=distance between two niches w=width of a niche d/w>1=coexistence d/w<1=exclusion |
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So if competitive exclusion drives species out of habitats or to extinction, why do we have so many species?
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Competing species are more likely to coexist when they use resources in different ways (i.e. resource partitioning) |
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What is resource partitioning?
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Species using a limited resource coexist by using it in different ways
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What is character displacement?
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species traits in sympatric populations diverge in response to competition (they encounter each other often because they live in the same area)
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what is competitive reversal?
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when speaking of the outcome of competition, this is when the inferior competitor in one habitat becomes the superior competitor in another
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Why do competitive reversals happen? Give some examples of one.
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this is an alternate strategy to deal with disturbance -k-selected= long lived and well defended -r-selected-short lived and low defense but opportunistic |
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what are fugitive species?
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a species that must disperse from one place to another as conditions change
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Describe when it looks like competition but it really isn't.
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Species appear to compete because their populations decline when they are together (sympatric), but not when they are apart (allopatric)
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If an organism feeds on another organism, it is called exploitation. What does this mean? What kind of interaction is this?
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this means one organism benefits by feeding on, and directly harming another +/- interaction |
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Define herbivore
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eats tissues or living plants or algae (consumer)
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Define predator.
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kills and eats other organisms (pray); some eat prey alive
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Define parasite
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lives in or on another organism (host), feeding on parts of it; usually doesn't kill it
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Define parasitoids
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spends most of life consuming a host, usually resulting in the hosts' death
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what are foraging modes? Name the foraging modes.
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this is the way in which predators search for food -active foragers -sit-and-wait predators |
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what are active foragers?
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these are predators that forage throughout their habitat
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what are sit-and-wait predators?
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these are predators that remain in one place and attack prey that move within striking distance
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name the types of sit-and-wait predators.
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ambush and sessile animals (animals that don't move and wait for prey to come to them)
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How do you measure a preference for a prey species?
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It's eaten in a greater proportion relative to its abundance.(like if they make up only 20% of the food population, but your diet consists of 80% that particular food)
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what are some costs of being a specialist?
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you would have to work harder to find food
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what are some benefits of being a specialist?
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there's less interspecific competition
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what are some costs of being a generalist?
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you would have to know how to catch multiple prey
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what are some benefits of being a generalist?
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you use less energy chasing specific food types
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what is a search image? How can it help an organism?
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it is an orientation toward a specific prey -it reduces the time it takes to locate a prey |
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Are search images fixed behaviors or learned?
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they can be fixed behaviors but are more often learned
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Summarize the point of search images.
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it's all about minimizing energy costs
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Define aposematism.
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warning coloration and chemical defense
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Define crypsis
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prey is camouflaged
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Define mimicry
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prey resembles another toxic or very fierce organism
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What are some anti-predator behavior?
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-changing foraging locations -being vigilant -defensive circles |
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Do plants have defenses?
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yes. structural and chemical defenses |
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What are examples of structural defenses in plants?
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tough leaves; spines and thorns
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What are examples of chemical defenses in plants?
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secondary compounds (toxic chemicals that discourage herbivory)
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Who is ahead- the predator or the prey?What is this called?
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the prey Life-Dinner Principle |
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why is the prey ahead in the arms race?
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Because if they aren't ahead, they're dead. if predators aren't ahead, they just miss a meal. not as detrimental |
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What happened in the Paine starfish experiment?
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-he removed the starfish to see how it would affect the community -led to the extinction of all large invertebrates besides mussels |
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What can be caused by exploitation of prey?
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oscillating cycles in predator and prey abundance. Predator abundance tracks prey abundance
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what are consumptive effects?
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reductions in prey density through predation
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what are non-consumptive effects?
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changes in prey behavior or physiology in response to predators; stress; non-lethal
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Define mutualism. what kind of interaction is it?
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a relationship where individuals of two species benefit +/+ interaction |
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Give some examples of mutualisms.
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-animals that get to eat parasites off another animal -bees pollinating flowers |
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T/F mutualisms are all symbiosis |
False
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Define symbiosis.
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a relationship in which the two species live in close physiological contact with each other
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What type of interaction is parasitism? commensalism?
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+/- +/0 |
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what is co-evolution?
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when two populations interact, each may evolve in response to characteristics of the other if it impacts an organisms reproduction
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what is specialization?
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the interaction of a species with a limited number of other species
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what are the types of mutualisms?
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-trophic, habitat, service, obligate, and facultative mutualism
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what is trophic mutualism?
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involves partners specialized in complementary ways to obtain energy and nutrients from each other
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what is habitat mutualism?
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involves species that receive a place to live, favorable habitat from their partners in return for defense or resources
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what is service mutualism? |
involve species that perform an ecological service for the other in exchange for resources
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Give an example of trophic mutualism.
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plants and fungi -fungi attach to roots and form extensions of these roots and increase the surface area for the plant to take up water and soil nutrients -fungi gets nutrients also |
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Give an example of habitat mutualism.
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Ants and acacia trees -ants provide protection to the trees -the trees provide shelter to the ants |
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Give an example of service mutualism.
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bird and crocodile -bird cleans crocodile's teeth -crocodile provides a meal for the bird |
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what is an obligate mutualism?
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Each species cannot exist without the other
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what is an facultative mutualism?
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the relationship b/w mutualists depends on the situation.
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Give an example of obligate mutualisms.
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ants and acacia trees
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Give an example of facultative mutualisms.
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aphids and ants -aphids provide "honeydew" for ants |
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what has to be true about the relationship of costs and benefits if a mutualism is to persist?
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cost > benefit
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define altruistic.
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social interaction that enhances the fitness of an unrelated recipient while reducing the fitness of the donor |
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why can't partners in a mutualism be altruistic?
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because organisms are selfish
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Why don't more organisms cheat?
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cheaters will be punished |
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what kind of interaction is commensalism?
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+/0 one species benefits but the other is not helped nor harmed |
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If one species does not benefit or suffer from the relationship, can Co-evolution occur?
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no
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give an example of commensalism.
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barnacles and whales
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what is taxonomic affinity?
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all closely related species in a community
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give example of taxonomic affinity.
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all birds of a particular genus
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what is a functional group?
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species that function in similar ways, but do not necessarily use the same resources |
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give an example of a functional group.
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all animals that feed by removing liquid nutrients from living organisms
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define guilds.
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group of species that use the same resources
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give example of guilds.
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all animals relying on floral resources for food
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name the trophic levels
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-Primary producers (autotrophs): plants and algae -Primary consumers: herbivores -Secondary consumers: carnivores -Tertiary consumers: carnivores |
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what is the OTHER definition of an omnivore?
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they eat from two different trophic levels (trophic omnivory)
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what can a horizontal interaction represent in an interaction web?
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competition
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define species richness.
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the number of species in a community
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define species evenness.
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relative abundances compared with one another
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define species diversity.
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a measure that combines species richness and species evenness
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define Shannon index
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determines species diversity
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what is biodiversity?
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describes diversity at multiple spatial scales, from genes to species to communities
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define direct interactions
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occur between two species (e.g., competition, predation, and facilitation)
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define indirect interactions
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occur when the relationship between two species is mediated by a third (or more) species
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give an example of an indirect interaction
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when wolves were reintroduced to Yellowstone park
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what is trophic facilitation?
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A consumer is indirectly facilitated by a positive interaction between its prey and another species
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define interaction strength.
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magnitude of the effect of one species on the abundance of another species
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what is a keystone species?
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they have a strong effect because of their role in the community -their effect is large in proportion to their biomass or abundance |
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give an example of a keystone species.
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the pisaster (star fish)
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What happened in the pisaster experiment?
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-measured interaction strength of (Pisaster) predation on mussels in wave-exposed versus wave-protected areas. -Pisaster was a less efficient predator where waves were crashing in |
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who has a large effect on communitydespite low abundanceand biomass
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keystone species
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who has a large effect on communitydue to high abundanceand biomass
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dominant/foundation species
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some dominant species are ecosystem engineers. what does this mean?
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they create, modify, or maintain physical habitat for themselves and other species.
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can keystone species be ecosystem engineers? if so, give an example.
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beavers because they can have a large impact by building dams
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