Lecture 7 pt. 2

Question 1

When faced with a selection pressure, species can _____

Answer 1

Show phenotypic plasticity

Question 2

what is Show phenotypic plasticity

Answer 2

that is, change their phenotype to one that can better deal with the selection pressure
Evolve or adapt
Go extinct

Question 3

Which of these happens depends on

Answer 3

the capacity for plasticity (can they actually change) the amount of phenotypic and genotypic variability the kind of selection pressure

Question 4

Which of these happens depends on the capacity for

Answer 4

plasticity, the amount of phenotypic and genotypic variability and the kind of selection pressure

Question 5

can Changes in global temperature alter the ecology or environment

Answer 5

Changes in global temperature can alter the ecology or environment

Question 6

what is PHENOTYPIC PLASTICITY

Answer 6

Organisms can respond by altering their phenotype, expressing different traits depending on the environmental conditions

Does not need to be genetically based

Question 7

However, if there is a genetic basis for particular behaviors, traits, or for phenotypic plasticity what happens

Answer 7

might see evolution of these traits

Question 8

Changes in global temperature can alter what

Answer 8

the ecology or environment

Question 9

Why wouldn’t all species evolve to breed as early as possible

Answer 9

Breeding is full of trade-offs
–breeding earlier can be risky but also more rewarding
For example, breeding earlier could result in more offspring
UNLESS
There is a cold snap in which case it could result in fewer offspring
How well different breeding phenotypes do will depend on:
–How stable and predictable the environment is
–How quickly individuals can recover from a failed breeding attempt
For example, can they breed more than once in a season?

Question 10

Selection will favor individuals that can:

Answer 10

Selection will favor individuals that can maximize their reproductive output

Question 11

what is Trophic Mismatch

Answer 11

Timing of things like migration and breeding need to coordinate with the timing of something else, in particular food availability
–lots of species time breeding and migration based on the availability of resources
when food and breeding or migration don’t align: called trophic mismatch

Changes in food availability influences populations that depend on that food –if possible, individuals alter the timing of migrations or breeding –otherwise, results in a population decline

Question 12

give an example of Trophic mismatch between the timing of reproduction and food availability

Answer 12

European great tit
Because of higher temperatures, caterpillars are showing up earlier
Some birds are more flexible and can lay eggs earlier
–this flexibility appears to be genetic.
Thus, birds with genes for more flexible egg-laying times are more successful
Selection for flexibility in an environment that is now more unpredictable
European great tits appear to be adapting

Question 13

what is Habitat Fragmentation

Answer 13

Often, there are maps of the range of particular species that look like this:
But in reality, that entire colored area is not all habitat
This is both because not all of the land will be suitable
species have particular niches and ecology that they survive best in
And also because all of that land may not be available

Question 14

what is apex predator

Answer 14

the one at the top

Question 15

why we would want these apex predators around:

Answer 15

this is a big question that ecologists have been working on
It turns out this sort of top-down control over the food web actually serves to keep many aspects of the ecosystem in balance

Question 16

Landscape-level effects of trophic cascades

Answer 16

Bass eat little fish–little fish eat protists— protists eat algae.
More bass = more protists = less algae (less algae= clearer water)
Sharks eat fish—fish eat coral More sharks = more coral
Bass eat minnows–minnows eat algae. Bass promote the growth of algae

Question 17

So to summarize, Predators are Important But they require particularly large habitats
Is there anything we can do about that?

Answer 17

There have been a number of reintroductions of predators into the wild, but without sufficient habitat this in itself won’t be effective
Current approaches to deal with habitat fragmentation include generating “corridors” which could connect distributed populations