Communities Flashcards
What does the yellow-bellied sapsucker do for other animals?
It makes sap wells (small round and large rectangular) which other animals such as hummingbirds and bats to feed.
What is one factor that may affect speciation?
effective population size
What is a deme?
a more concrete, smaller isolated population
which evolves faster…small demes or large demes?
small demes
Why are eastern screech owls more red in thick forrests?
they blend into the red bark of the forests and have greater survival
Tell me about hybrid inferiority.
- mixture between two different species
- makes male displays difficult because they don’t have the full genetic purity for one display so it incorporates both species’ display into one which makes it difficult to compete with the pure displays
- sometimes if two species mate, the eggs won’t hatch.
What is Haldane’s rule?
- the heterogametic sex (the gender with different gametes ex: XY or ZW) is most likely to be infertile.
F1 vs F2 breakdown…what are these?
- F1 breakdown is when the first hybrid generation cannot reproduce.
- F2 breakdown is when the second hybrid generation cannot reproduce.
What is a hybrid zone?
it is the area of land where two different species intermingle and interbreed producing hybrids
What is a stable hybrid zone?
this is a hybrid zone that remains constant and does not expand or contract.
What two factors affect the species pool?
1) speciation
2) regional extinction
what two factors drive community dynamics?
1) immigration
2) emigration
what two factors influence community dynamics?
1) resources
2) species interactions
MAKE SURE YOU LOOK UP THE PATTERN OF COMMUNITIES GRAPH FROM CHAPTER 20…
- x-axis starts with most common birds and progresses to least common birds
- y-axis is just a measurement of how much of one bird is present in community
- the five most common species make up 55% of birds in the entire community
Name some trophic levels.
predators, insectivores, herbivores
define “niches”
- requirements for a species
- the role or job of a species
Why are islands great for studying populations?
- they usually have isolated communities
- concepts can be extrapolated and applied to continents
what is turnover?
- the addition and loss of species
- makes populations different after a few years
As the rate of immigration increases what happens?
- resources are more and more depleted
- fewer niches are available
- extinction rate increases
What main factor affects immigration rate on islands?
- island distance from the mainland
- immigration rate is higher on closer islands, lower on farther islands.
What main factor affects extinction rate on islands?
- the size of the island
- extinction rate is higher on smaller islands, lower on larger islands.
What are open communities?
- disturbance focused
- species are just responding to environmental cues
- not much species interaction
What are closed communities?
- equilibrium focused
- competition/species interactions are very important
What is an ecotone?
this is a division between two closed communities
Define Alpha diversity
- number of species (or diversity) within a local habitat
define Beta diversity
- number of species (or diversity) among or across multiple local habitats
define Gamma diversity
- number of species (or diversity) within a really large region (ex: new jersey)
