Evolution 3 & Evolution 4

Question 1

Describe stratigraphy

Answer 1

o Assumes rocks above others= younger than those below
o Chronological age relative to older (deeper) or younger (surface)
o May be incorrect (geological processes)

Question 2

Define anagenesis

Answer 2

(change within a lineage)

Question 3

define cladogenesis

Answer 3

formation of one or more species (speciation) from another over time

Question 4

relationship between clad and anagenesis

Answer 4

Cladogenesis= formation of one or more species (speciation) from another over time (branching evolution) > followed by straight line anagenesis

Question 5

What is the fossil record evidence for

Answer 5

perpetual change 
common ancestry
evolut/ trends
intermediate forms
evolutionary failure 
evolutionary stability

Question 6

does the fossil record provide evidence for fact course or mechanism

Answer 6

fact and course

Question 7

explain perpetual change

Answer 7

oldest= simple, current= complex shows change

Question 8

explain evolution failure & stability

Answer 8

o Evolutionary failure: not enough variation to survive change + selective pressures
o Evolutionary stability: little selection pressures= small change of evolutionary time

Question 9

comparative anatomy and embryology both show what evidence

Answer 9

common ancestry, + phylogenetic constraint

Question 10

define phylogenetic constraint

Answer 10

evolution constrained by ancestry, can only evolve from what was previously there

Question 11

explain homologies

Answer 11

Organs modified for different functions

o But all share common, underlying anatomical plan

Question 12

define vestigial

Answer 12

Organ having become functionless in course of evolution

Question 13

why are vestigial organs not lost fully, and why is the feature not necessary

Answer 13

• Why haven’t lost completely: difficult to eliminate genes that control creation
• Feature not necessary- is minimised so not to use up energy for its maintenance

Question 14

what are atavistic features

Answer 14

genetic throwback

Question 15

what are analogous features evidence of

Answer 15

convergent evolution

Question 16

define convergent evolution

Answer 16

independent evolution of trait in rather distinctive evolutionary lines

• separate lineages becoming similar because of similar lifestyles
• results in features similar in function, but evolved independently (= analogous features)

Question 17

similar answers to similar selection pressures describes what

Answer 17

analogous features

Question 18

what are the three features related to ancestry, function and appearance

Answer 18

homology= ancestry 
analogy= function 
homoplasy= appearance

Question 19

what is artificial selection produce evidence for

Answer 19

mechanism of natural selection rather than just the fact of evolution

Question 20

define adaptive radiation

Answer 20

Formation of many new species following availability of new environments or development of new adaption
- Radiation of species to fill available niches

Question 21

what do you need for evolution and won’t occur if there isn’t

Answer 21

• Need:
  o System of reproduction
  o Inherited variation- genetic differences (mutation)
  o Differential reproductive success (aka fitness)
• None will occur if there isn’t:
  o Changing environment
  o Selective pressures

Question 22

is evolution random

Answer 22

• Evolution is not random (its process can be but not evolution itself)

Question 23

does natural selection produce perfect organism

Answer 23

o Acting on individuals in environment at that time

o Can only get variation on what was previously there