Biol 415: Lecture 4 (9/3/15)

Front 1

Name all four of Darwin's postulates

Back 1

1. The individuals within a population differ from one another (variation within a population).

2. The differences are, at least in part passed from parents to offspring (variation is heritable)

3. Some individuals are more successful at surviving and reproducing than others (differential fitness).

4. The success in survival and reproduction is associated with variant traits that are heritable.

Front 2

What gene has been seen to change fur color in mice and the red hair color in humans?

Back 2

MC1R

Front 3

Explain the graph

Back 3

The graph is indicating the amount of reflectance of the MC1R. It was found that those with dd have the highest reflectance indicating that they are responsible for light coat color.

Front 4

Explain how Pocket mice obtained different coat colors

Back 4

Lava islands have formed separarated by sand. Mice populations at each lava island evolved dark coat colors from different mutations of the MC1 receptor gene for hair pigmentation. Unlike most evolutionary traits which have occured due to one mutation. This trait (dark fur color) arose independently in different mutations at the same time. Thus the way in which these mutations are a result of convergent evolution and therefore an example of analogy and not homology.

Front 5

The pocket mice have evolved dark fur through a mutation of the MC1 receptor. However this is an example of analogy and not homology. Given that the pocket mice all arose from a common ancestor explain why this is an example of analogy and not homology

Back 5

Analogy is defined as the development of a trait due to mutations that occured multiple times. Homology is a result of a trait arising from a single mutation. The pocket mice evolved dark fur as a result of analogy because each population evolved the MC1 receptor mutation independenty.

Front 6

Dark pigmentation is often ________________

Back 6

Analogous

Front 7

Explain how predation is a selective factor in regards to whether dark or light fur animals survive in a given environment

Back 7

Variations prior to predation are always present. Spontaneous mutations which can cause a difference in fur color can infer an advantage in a particular environment. If in a dark environment a spontaneous mutation caused otherwise light colored fur mice to change to dark color fur then the dark color fur would be able to evade predation much easier than that of the light color fur mice. Eventually the light color fur mice numbers will lessen while the dark colored fur mice increased.

Front 8

T/F: The finches found throughout the Galapagos Islands are considered individual species because they are geographically isolated.

Back 8

true

Front 9

Using the graph provided. Can you say that beak size and shape is inherited?

Back 9

Yes, There is a correlation of beak sizes between generations implying that beak size is inherited

Front 10

Draw a graph displaying a trait of no heritability

Back 10

This graph shows that there is no heritability

Front 11

Draw a graph displaying a trait of medium heritability

Back 11

This graph shows that there is medium heritability

Front 12

Draw a graph displaying a trait of Strong heritability

Back 12

Front 13

What gene is responsible for bone/beak formation

Back 13

BMP4

Front 14

High expression of BMP4 results in

Back 14

Large beaks

Front 15

Are survival and reproduction nonrandomly associated with beak depth?

Back 15

Yes

Front 16

During droughts, it has been shown that finches with __________ sized beaks survived better causing a shift in the population towards the ____________ sized beaks

Back 16

Large

Front 17

T/F: All natural selection is directional

Back 17

False. There are three types of natural selection: Directional, Stabilizing, and disruptive

Front 18

Draw a graph before and after an event resulting in directional selection?

Back 18

The first graph shows before an event.

The last graph shows after an event

Front 19

Draw a graph before and after an event resulting in Stabilizing selection?

Back 19

The first graph shows before an event

The last graph shows after an event

Front 20

Draw a graph before and after an event resulting in disruptive selection?

Back 20

The first graph shows before an event

The last graph shows after an event

Front 21

Define Directional Selection

Back 21

A form of natural selection in which an event has caused one trait to be advantageous over another causing an increase in reproduction of that trait over the other.

Front 22

Define Stabilizing selection

Back 22

A form of natural selection in which a medial trait is favored over the extremes. This is more commonly understood in terms of genotype where the heterozygous genotypes are favored over the homozygous for whatever reason either they confer some kind of disadvantage from predators, reproduction, or health.

Front 23

Define disruptive selection

Back 23

A form of natural selection in which the heterozygous genotype is unfavored and the two homozygous genotypes are favored.

Front 24

When the Darwin/Wallace theory of natural selection is summarized, four central postulates emerged. Which of the following is not one of these four natural selection postulates?

A. Variations exist in any given generation of a species

B. Those individuals whose variations confer an advantage are more likely to survive and reproduce

C. variations are, at least in part, heritable.

D. variations in traits are produced by mutations

Back 24

D. Variations in traits are produced by mutations

Front 25

What can we conclude from the snapdragon experiment on the left?

A. The white flowers have a selective disadvantage over the yellow flowers

B. The population has evolved higher percentage of yellow flowers.

C. The flower color is not heritable

D. Selection acts in favor of white flowers

E. The population has not evolved.

Back 25

D. Selection acts in favor of white flowers

Front 26

T/F: Individuals evolve

Back 26

False. Individuals don't evolve, populations do.

Front 27

T/F: Populations evolve only if the traits are heritable

Back 27

True

Front 28

Natural selection acts on _________________ phenotypes, but evolution consists of changes in _______________

Back 28

Phenotypes ; Genotypes

Front 29

T/F: Phenotypes can change in response to enironmental conditions without necessarily changing the genotype

Back 29

True. this is an instance of phenotypic plasticity

Front 30

The ability of one genotype to produce more than one phenotpe when exposed to different environments

Back 30

Phenotypic plasticity

Front 31

T/F: Phenotypic plasticity is an example of natural selection

Back 31

False. Since phenotypic plasticity is the result of a genotype producing more than one phenotype when exposed to different environments and does not result in a change in genotype than it is not natural selection.

Front 32

T/F: Evolution involves individuals changing in order to adapt to their environment

Back 32

False. Individuals do not change in order to adapt to their environment.

Front 33

Give an example of phenotypic plasticity

Back 33

When a fish is placed in a small bowl than it is limited in it's ability to grow. Normally it would just grow as large as its surrounding allow. If you transfer it to a larger bowl than it will grow larger. This is not a heritable trait.

Front 34

T/F: Phenotypic plasticity is heritable

Back 34

False.

Front 35

T/F: Organisms can adapt to future conditions

Back 35

False.

Front 36

T/F: Evolution is always a generation behind any changes in the environment

Back 36

True

Front 37

T/F: Natural selection can only amplify or diminish heritable variations

Back 37

True

Front 38

T/F: Selection cannot create new traits

Back 38

True

Front 39

T/F: Natural selection cannot act on variations that an individual acquires during its life, even if these variations are useful

Back 39

True

Front 40

If natural selection does not introduce new traits, then where do new traits come from?

Back 40

Mutation and recombination

Front 41

T/F: Advantageous mutations are a response to environmental stresses

Back 41

False. Advantageous mutation is a matter of luck

Front 42

T/F: Multiple mutations can have the same advantageous effect

Back 42

True