Natural Selection and Evolution

Question 1

start of life on earth

Answer 1

hydrogen formed and heavier elements formed in stars and early chemical reactions took place

Question 2

eukaryotic cells

Answer 2

cells that contain a membrane bound nucleus, appeared in the proterozoic aeon

Question 3

fossil record

Answer 3

• cast
• impression fossils
• petrification

Question 4

conditions for fossilisation

Answer 4

• quick burial of organism
• layers of sediments build up
• left for a long period of time
• erosion and uplifting exposes fossils to the earth’s surface

Question 5

relative dating

Answer 5

• Law of Superposition - old deep sedimentary young shallow
• measures the layers of rock (strata)
• use index fossils that have been absolute dated

Question 6

absolute dating

Answer 6

radiometric dating
carbon dating

Question 7

radiometric dating

Answer 7

how long it takes half of the atoms in a sample to decay into another element

Question 8

carbon dating

Answer 8

can’t be used for fossils over 50 000 years. when an organism dies carbon 14 begins to decay at a constant rate

Question 9

evidence for evolution from fossils

Answer 9

• presence of simpler life forms to more complex life forms in the fossil record
• presence of transitional forms of organisms that have features of old organisms with new

Question 10

statements of natural selection

Answer 10

1. there is variation within a population of a species
2. if a factor in the environment changes, so may what is favourable for survival
3. Those with traits most suited to the new environment are most likely to survive
4. The trait becomes more prevalent in the population

Question 11

evolution

Answer 11

the gradual development of new species from a common ancestor

Question 12

what drives evolution

Answer 12

• there is a struggle for existence, must compete for food, mates and habitats

Question 13

evidence for evolution

Answer 13

• biochemical evidence of cytochrome c (protein that undergoes very little mutations)
• comparative anatomy (similar structures present) (homologous structures)
• comparative embryology comparing development in the womb)
• biogeography

Question 14

analogous structures

Answer 14

evolved independently to serve the same purpose

Question 15

vestigial structures

Answer 15

served an important function in an ancestor but not in the modern organism

Question 16

atavism

Answer 16

the reappearance of an ancestral form (evidences for previous evolution)

Question 17

2 forms of biogeography

Answer 17

• isolation (when a species are separated)
• migration (where members of a species move)

Question 18

antibiotic resistance

Answer 18

bacteria develop resistance to antibiotics rapidly
- vertically (new generations inherit gene from parent cell obtained from mutation)
- horizontally (resistance genes are transferred directly through transposons)