Speciation and evolution Flashcards
1
Q
Why might people oppose evolution
A
- contrary to teaching of bible
- religion holds belief of creationism
- implies man not made in God’s image
- lack of evidence for evolution
2
Q
How an organism could evolve into separate species
A
- interruption of gene flow between specie (no breeding between)
- sympatry speciation, e.g. changes in breeding times
- allopatry speciation, e.g. river
- different conditions either side of barrier
- different selection pressures, different alleles selected for
- formation of two different gene pools
- difference in physical characteristics
- cannot breed to produce fertile offspring
3
Q
How might tree species spread
A
- seed dispersal by wind and animals
- adaptions of fruits that aid dispersal by wind, e.g. wings, parachute
- adaptions of animals, e.g. hooks which stick to animals fur
4
Q
Why do animals share the same scientific name
A
- same genus, reflects close relationship
5
Q
Explain how differences in species have arisen
A
- isolation of populations, e.g. reproductive isolation
- mutations cannot pass between populations
- genetic drift
- different selection pressures
- different allele frequencies, due to difference effects of local conditions
6
Q
Why might there be controversy over conservation
A
- requires coordination between governments
- governments might have different approaches to conservation, e.g. tourism
- might have different needs for local populations, different wealth of countries
7
Q
Why are mules unable to produce offspring
A
- horse: 2n = 64, donkey: 2n = 62
- mule: 32 + 31 = 63
- cannot form gametes
- chromosome pairing not possible during meiosis
8
Q
What is meant by the term isolating mechanism
A
- isolating mechanism prevent interbreeding between specie populations, barrier to reproduction
9
Q
What is meant by post-zygotic isolating mechanism
A
- postzygotic mechanisms allow mating/fertilisation
- but prevent production of viable fertile offspring or prevent offspring developing healthly
10
Q
Species
A
- species is a group of organisms that can interbreed to produce fertile offspring
11
Q
Explain what is meant by gene mutation
A
- change in DNA
- change, deletion, addition, duplication, substitution of bases
12
Q
Explain how allele frequency for a mutation changes as forest develops
A
- change in allele frequency, mutant frequency increases
- reproductive success of mutant
- pass on of mutant allele
- as forest develops, more shaded, less photosynthesis possible, photosynthetic individuals die
