Communities

Question 1

What does the yellow-bellied sapsucker do for other animals?

Answer 1

It makes sap wells (small round and large rectangular) which other animals such as hummingbirds and bats to feed.

Question 2

What is one factor that may affect speciation?

Answer 2

effective population size

Question 3

What is a deme?

Answer 3

a more concrete, smaller isolated population

Question 4

which evolves faster…small demes or large demes?

Answer 4

small demes

Question 5

Why are eastern screech owls more red in thick forrests?

Answer 5

they blend into the red bark of the forests and have greater survival

Question 6

Tell me about hybrid inferiority.

Answer 6

• 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.

Question 7

What is Haldane’s rule?

Answer 7

• the heterogametic sex (the gender with different gametes ex: XY or ZW) is most likely to be infertile.

Question 8

F1 vs F2 breakdown…what are these?

Answer 8

• F1 breakdown is when the first hybrid generation cannot reproduce.
• F2 breakdown is when the second hybrid generation cannot reproduce.

Question 9

What is a hybrid zone?

Answer 9

it is the area of land where two different species intermingle and interbreed producing hybrids

Question 10

What is a stable hybrid zone?

Answer 10

this is a hybrid zone that remains constant and does not expand or contract.

Question 11

What two factors affect the species pool?

Answer 11

1) speciation

2) regional extinction

Question 12

what two factors drive community dynamics?

Answer 12

1) immigration

2) emigration

Question 13

what two factors influence community dynamics?

Answer 13

1) resources

2) species interactions

Question 14

MAKE SURE YOU LOOK UP THE PATTERN OF COMMUNITIES GRAPH FROM CHAPTER 20…

Answer 14

• 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

Question 15

Name some trophic levels.

Answer 15

predators, insectivores, herbivores

Question 16

define “niches”

Answer 16

• requirements for a species

- the role or job of a species

Question 17

Why are islands great for studying populations?

Answer 17

• they usually have isolated communities

- concepts can be extrapolated and applied to continents

Question 18

what is turnover?

Answer 18

• the addition and loss of species

- makes populations different after a few years

Question 19

As the rate of immigration increases what happens?

Answer 19

• resources are more and more depleted
• fewer niches are available
• extinction rate increases

Question 20

What main factor affects immigration rate on islands?

Answer 20

• island distance from the mainland

- immigration rate is higher on closer islands, lower on farther islands.

Question 21

What main factor affects extinction rate on islands?

Answer 21

• the size of the island

- extinction rate is higher on smaller islands, lower on larger islands.

Question 22

What are open communities?

Answer 22

• disturbance focused
• species are just responding to environmental cues
• not much species interaction

Question 23

What are closed communities?

Answer 23

• equilibrium focused

- competition/species interactions are very important

Question 24

What is an ecotone?

Answer 24

this is a division between two closed communities

Question 25

Define Alpha diversity

Answer 25

• number of species (or diversity) within a local habitat

Question 26

define Beta diversity

Answer 26

• number of species (or diversity) among or across multiple local habitats

Question 27

define Gamma diversity

Answer 27

• number of species (or diversity) within a really large region (ex: new jersey)