Flashcards in Lecture 19 and 20- community ecology Deck (109)
What is a community?
The species that live and interact in an area
What did detailed studies of plant distribution in Siskiyou mountains of oregon show?
Different combinations of plant species are found at different locations- species enter and drop out of communities independent over environmental gradients
What did Frederick Clements argue?
plant communities were tightly integrated “superorganisms.” Communities in similar areas would have the same species.
What did Henry Gleason argue?
plant communities are loose associations of species; each species was distributed based on its own
What can organisms be divided into based on the source of their energy?
Autotrophic plants constitute a trophic level called...
(Photosynthesizers), primary producers
Heterotrophs that eat autotrophs are called...
herbivores or primary consumers
Organisms that eat herbivores are called...
Another type of trophic level is...
Organisms that obtain food from more than one trophic level are called...
A sequence of interactions in which a plant is eaten by a herbivore which in turn is eaten by a secondary consumer and so on can be diagrammed as a...
Food chains are interconnected to make...
a food web
Food webs help us to understand what?
The trophic interactions among organisms in an ecosystem
What are the 5 main ways that organisms interact with one another?
-Predation or parasitism
What are commensalism interactions?
Interactions in which one participant benefits and the other in unaffected
What are amensalism interactions?
Interactions in which one participant is harmed and the other unaffected
What effect do these 5 types of interactions have?
Influence population densities of a species, restrict range of conditions under which animals exist.
What does mutualism do?
Increases the range of physical conditions under which a species can persist
How do predator and prey population change?
Why do predator and prey populations oscillate?
Predators cause fluctuations in prey densities, growth of predator population lags behind growth of prey populations.
Give an example of predator-prey interactions.
Arctic lemmings (prey) and predators: arctic fox, snowy owl, jaegers, 3-4 year oscillations
Give another example of predator-prey interactions.
Canadian lynx (Lynx canadensis) and snowshoe hares (Lepus americanus) with 9-11 year cycle
How was it proven that oscillations are driven by both lynx predation and interactions between hares and their food supply?
They enclosed some areas with fences through which hares but not lynx could pass, and provided food in some areas.
what do predators also restrict?
The range of a species
What is the Australasian biogeographic region home to?
A group of birds-megapodes, also called mound builders- who do not incubate their eggs.
How do megapodes keep their eggs warm?
By laying their eggs in a mound of decomposing vegetable material
Megapodes are good dispersers. Why are they absent from all islands with Asian mammalian predators?
What are the two types of mimicry?
What is Batesian mimicry?
Palatable species mimic unpalatable or noxious species