CH10 evolution Flashcards
1
Q
What is evolution
A
- theory that describes the way in which organisms evolve, or change
2
Q
How does evolution occur
A
- organisms best suited to their environment are more likely to survive and reproduce, passing on characteristics to their offspring
- gradually, a species changes over time to have a more advantageous phenotype for the environment in which it lives
3
Q
A
3
Q
Where did darwin carry out observations
A
- Galapapos islands
4
Q
What were darwins observations of finches
A
- different islands had different finches, with different beaks and claws
- design of finches beaks were linked with food available on each island
5
Q
Evidence for evolution
A
- palaeontology
- comparative anatomy
- comparative biochemistry
6
Q
Palaeontology
A
- the study of fossils and the fossil record
7
Q
How are fossils formed
A
- when animal and plant remains are preserved in rocks
- over time, sediment is deposited on the earth to form layers of rock
- different layers correspond to different geological eras
8
Q
What evidence is provided by the fossil record
A
- fossils of simpler organisms are found in the older rocks
- sequence in which organisms are found matches their ecological links to eachother
- can see how closely related organisms have evolved from the same anscestor
- fossils allow relationships between extinct and living to be investigated
9
Q
Why is fossil record incomplete
A
- many organisms are soft bodied and decompose before fossilisation
- many fossils have been destroyed by geological activity
- many fossils are still undiscovered
10
Q
Comparative anatomy
A
- study of similarities and differences in the anatomy of different living species
11
Q
Homolygous structures
A
- a structure that appears superficially different in different organisms but has the same underlying structure
12
Q
Example of homologous structure
A
- limbs in vertebrates
- very similar among organisms, shows vertebrate limbs have evolved from common anscestor
- evidence of divergent evolution
13
Q
Divergent evolution
A
- different species have evolved from a common anscestor
14
Q
Comparative biochemistry
A
- study of similarities and differences in proteins and other molecules that control life processes
15
Q
Most studied molecules in comparative biochemistry
A
- cytochrome c
- ribosomal rna
16
Q
Hypothesis of neutral evolution
A
- most of variability in structure of a molecule does not affect its function as occurs outside molecules functional region
- changes that do not affect function are ‘neutral’
17
Q
How to discover how closely related species are with comp biochem
A
- molecular sequence of a particular molecule is compared
- number of differences are plotted against rate molecule undergoes neutral base pair substitution
- scientists can use this information to estimate point when two species last shared a common anscestor
- more closely related species have more similar dna and proteins
18
Q
Why is ribosomal rna used to determine relationships between ancient species
A
- slow rate of substitution
- used with fossil information
20
Q
A
