19-processes Of Evolution

Question 1

Evolution

Answer 1

Change in the genetic makeup of a population over time.

Question 2

European mindset in 18th century: (regarding species)

Answer 2

• species are unchanging
• uniquely designed for their environment
• earth only 6,000 yrs old
• strong religious (Christian) influence

Question 3

Jean Baptist Lamarck (Lamarck’s Folly, 1809)

Answer 3

• use and disuse
• inheritance of acquired characteristics

-refuted By Weismann in 1890 (mouse tails)

Question 4

Charles Darwin

Answer 4

• made observations in South America that organisms changed over time
• Galapagos islands

Question 5

Adaptations

Answer 5

Inherited characteristics of organisms that enhance survival and reproduction in a given environment

Question 6

Natural Selection

Answer 6

Individuals with certain inherited traits tend to survive and reproduce better, due to these traits

Question 7

Origin of species

Answer 7

• Darwin and Wallaces publishing on evolutionary theory
  - diversity of life
  - unity of life
  - match between organisms ad their environment
• Used artificial selection as compelling evidence
• Common ancestor

Question 8

!!!!

Answer 8

• population =smallest unit that can evolve
• evolution requires genetic variation in the gene pool of a population
• Mendel’s work in genetics strengthened Darwin’s argument
• “tree of life” (phylogenies trees, cladistics)
• change in allele frequency over time

Question 9

Genetic Variation

Answer 9

Differences among individuals in the composition of their genes

Question 10

Sources of Genetic variation

Answer 10

• Mutation*
• Gene-duplication
• Sexual reproduction

Question 11

Mutation

Answer 11

• Random change in DNA nucleotide sequence

- Driving force for all other variation

Question 12

gene-duplication

Answer 12

-Chromosomal sections may be copied twice during replication
(4 possible outcomes) (notes)

Question 13

sexual reproduction

Answer 13

• independent assortment
• crossing over
• Random fertilization

Question 14

Micro evolution

Answer 14

Evolutionary change at the smallest level (population)

• mutation
• Natural Selection
• Genetic drift
• gene flow
• sexual selection

Question 15

Natural selection

Answer 15

• *mutation is still the driving force
• those with beneficial traits produce more offspring
  
  • traits become more common

Question 16

Genetic drift

Answer 16

• Random events that cause allele frequencies to fluctuate unpredictably
  
  • founder events
  • bottlenecks

Question 17

Gene flow

Answer 17

• movement of fertile individuals (or their gametes) into or out of a population
  
  • immigration (in)
  • emigration (exit)

Question 18

Sexual selection

Answer 18

• individuals with certain characteristics are more likely to obtain mates
  
  • Intrasexual selection (competition between same sex individuals)
  • Intersexual selection (mating choice)
• Drawbacks…
  
  • best trait for mating is not always good for survival

Question 19

Hardy-Weinberg Equilibrium

Answer 19

• p + q = 1
• p^2 + 2pq + q^2 = 1
  
  • p = frequency of dominant allele
  • q = frequency of recessive allele
  • p^2 = DD
  • q^2 = dd
  • 2pq = Dd

Question 20

Conditions for H.W Equilibrium

Answer 20

• no mutation
• no natural selection
• infinite population
• no gene flow
• random mating
• very rare

Question 21

Types of Natural selection

Answer 21

Directional selection 
   -favors 1 extreme
Stabilizing selection
   -favors intermediate 
Disruptive selection 
   -favors both extremes

Question 22

Limitations of Natural Selection

Answer 22

• selection can only act on existing conditions
• limited by historical constraint
• adaptations have drawbacks
• things change at random in nature