Lecture 13.1/13.2 Intro to Evolutionary Mechanisms

Question 1

Evolution?

Answer 1

• Change over time
• refer to a change in allele frequencies

Question 2

Evidence of Evolutonary Change?

Answer 2

• Geology
• Historical Biogeography
• Comparative Embryology
• Comparative Morphology
• Comparative Genetics

Question 3

Geology

Answer 3

• Fossil records documents continuity
• Darwin’s theory proposes all species that have ever lived are related

Question 4

Historical Biogeography

Answer 4

in relation to landforms (earthquakes creating barriers that makes animals evolve differently)

Question 5

Comparative Embryology

Answer 5

Early embryos of related species are similar

Question 6

Comparative Morphology

Answer 6

reflects common ancestry (may have different functions human forearm and bat wings)

note: homologous structures

Question 7

Comparative Genetics

Answer 7

Homologies (similarities in DNA) can also be present at the molecular level

• a wooly mammoth and our current elephants
• humans to mouse

Question 8

Fact about Wooly Mammoth?

Answer 8

In molecular homologies they are related to the Asian Elephant

Question 9

Microevolution?

Answer 9

Describes small-scale genetic changes in population

Question 10

Macroevolution?

Answer 10

• Describes large scale evolutionary chages
• results from microevolution over millions of years

Question 11

Genotype

Answer 11

genetic make-up of an organism

Question 12

Phenotype

Answer 12

observable or expressed traits of an indiviual

(size, height, hair color)

ex: a flower may have the same genotype but the phenotype is different based on enviornment. Like a flower that has different colors.

Question 13

What are the two types of genetic variation

Answer 13

• new alleles via mutation
• rearrangment of exsiting alleles into new combination via sexual reproduction

Question 14

Why do mutation happen?

Are they good or bad?

Answer 14

Mutations arise randomly with respect to “needs”

• Can be deleterious - harmful
• Advantageous - benefit
• Neutral mutations- no benefit but also not harmful

Question 15

Sexual Reproducation?

Answer 15

• is another source of variation
  
  • does not generate new alleles but it generates new combinations of alleles

Question 16

Quantitive variation?

Answer 16

• broad curves indicates lots of vartiations
• narrow curves indicate little variation

ex: height

Question 17

Qualitative variation?

Answer 17

traits that are discrete and do not vary continuously

• discrete phenotypes
  
  • Ex: albanism, tounge rolling, widows peak

Question 19

Hardy & Weinberg principle?

Answer 19

it specifies the condition in which evolution would not occur

• alleles frequencies will not change

Question 20

Genetic equilibrium is possible only if?

Answer 20

• no mutation occurs
• population is closed to migration-no new individuals
• population is infinite in size
• all genotype survive and reproduce equally well
• mate randomly with respect to genotype

this will never happen!

Question 21

Relative Fitness?

Answer 21

Number of surviving offspring that an individual produces compared with others in the population

• Being able to reproduce and survive

Question 22

Example of evolution by Natural Selection?

Answer 22

Pesticide resistance

Ex: roaches at first they die off because they are not resistant to RAID, the ones that are resistant reproduce offspring that are resistant to RAID.

Coat Coloring

Ex: mice coat color darker mice didnt survive in the beach but lighter coated mice did because they blended in better

Question 23

Adaptation

Answer 23

increase survival and reproduction in a given enviornment

Product- increases the relative fitness of an organism in its enviornment

Process- accumulation of adaptive traits over time

Question 24

Two forms of adaptation?

Answer 24

Physical- camouflage, hair, large ears, flashy plumage

Behavior- group living, migration, hibernation, defensive postures

Question 25

Directional Selection?

Answer 25

shifting from an existing mean to a more favored mean

Ex: small horses —-> larger horses

Question 26

Natrual Selection?

Answer 26

• Differential survival and reproduction of individuals in a population based on heritable variation in their phenotype

Question 27

Does natural selection produce perfect organisms?

Answer 27

No, there has to be a trade off

Question 28

Disruptive selection?

Answer 28

favors extreme phenotypes over intermediate phenotype

Ex: larger beaks or smaller beaks in order to open there food. Medium beaks wouldnt be able to open anything

Question 29

Stabilizing Selection?

Answer 29

when intermediate phenotypes are favored

Ex: small infants and to large infants are not likely to survive, favoring the mean or medium infants.

Question 30

Do individuals evolve?

Answer 30

No, individuals DO NOT evolve, populations do!