7/ evidence for evolution

Question 1

outline 6 evidence for evolution areas

Answer 1

• artificial selection - human generated evolution
• variation in space
• fossil record
• homology - evidence from morphology
• experimental evolution - generating evolution in a lab
• observable evolution

Question 2

artificial selection

Answer 2

• pigeons used as example by darwin, humans selecting on morphology
• dogs
• crops - eichorn to heritage wheat to modern wheat. more powerful than genetic engineering
• crops - beta vulgaris to sugar beat, beetroot and chard
• new species - hybrids

Question 3

where does artificial selection generate new species

Answer 3

• hybrids
• primula kewensis hybrid between primulas verticilliata and floribunda
• speciation through allopolyploidy - doubled chromosome number
• instant speciation
  40-70% of plants are polyploids

Question 4

bergmanns rule

Answer 4

animals get larger further north

Question 5

allens rule

Answer 5

animals in colder climates have thicker limbs

Question 6

lacks rule

Answer 6

the clutch size of each species has evolved to an evolutionary optimum

Question 7

renschs rule

Answer 7

sexual dimorphism increases w average body size

Question 8

what are these biological rules showing, limitations

Answer 8

• rules don’t always work
• common adaptive responses of organisms in dif places

Question 9

foxes morphology changes north to south America

Answer 9

• north: larger, thicker fur, smaller ears, thicker limbs

Question 10

herring gul and lesser black backed gul

Answer 10

• ecologically similar
• at 2 dif ends of evolutionary chain

Question 11

chages in space? sparrows

Answer 11

• Italian sparrow occurs in area of overlap of house and spanish sparrow
• arose as a hybrid between them
• now a distinct species

Question 12

evolution of horses

Answer 12

• teeth got larger and more crevices
• morphology of forelimb changed
• modern horse has hoof - escape predators

Question 13

what are transitional forms

Answer 13

• in ref to fossils - evolutionary links between major groups

Question 14

homologous characters

Answer 14

• traits inherited from a common ancestor
• although they are inherited they may share dif functions

Question 15

example of homology bats and birds

Answer 15

• limbs are homologous
• 2 pairs - arms and legs, share same bones
• also non - homologous/ analogous due to difs

Question 16

vestigial characters

Answer 16

• extant organisms have structures which serve no function
• presence serves as evidence of evolutionary relationships and change

Question 17

universal homologies

Answer 17

• triplet coding

Question 18

how do you show evolution in a lab

Answer 18

• fast reproducing organisms
• e coli proliferated for 73 500 generations (only 7500 generations in human history)
• 12 founding populations all showed same evolutionary response to the conditions