Evolution

Question 1

What is the theory of evolution?

Answer 1

All of today’s species have evolved from simple life forms that first started to develop over three billion years ago

Question 2

What did Darwin know?

Answer 2

Organisms in species show wide variation in their characteristics (phenotypic variation) bc of differences in genes + organisms have to complete for limited resources

Question 3

What did Darwin conclude from his findings?

Answer 3

Organisms with most suitable characteristics for environment = most successful competitors & most likely to survive aka ‘Survival of the fittest’

Question 4

What are successful organism that survive most likely to do?

Answer 4

Most likely to reproduce and pass on genes to offspring

Question 5

What are organisms that less well adapted less likely to do?

Answer 5

Less likely to survive & reproduce + to pass genes on to next generation

Question 6

Name 3 things that supported Darwin’s hypotheses

Answer 6

• Discovery of genetics
• Bacteria are becoming more resistant to antibiotics
• Fossils of different ages (fossil record)

Question 7

Explain how the discovery of genetics supported Darwin’s hypothese

Answer 7

Provided explanation of how organisms born with beneficial characteristics can pass them on

Question 8

Explain how bacteria being resistant to antibiotics supported Darwin’s hypothese

Answer 8

Bacteria are able to evolve to become resistant to antibiotics → support evolution by natural selection

Question 9

Explain how the fossil record supported Darwin’s hypothese

Answer 9

Shows how changes in organisms developed slowly over time

Question 10

Name 3 reasons why not everyone agreed with Darwin’s theory

Answer 10

1. Went against common religious beliefs
2. Darwin couldn’t explain why new, useful characteristics appeared or how they passed on
3. There wasn’t enough evidence to convince many scientists

Question 11

What is speciation?

Answer 11

The development of a new species

Question 12

When does speciation occur?

Answer 12

Happens when populations of same species become so different → can no longer successfully interbreed to produce fertile offspring

Question 13

How does speciation occur?

Answer 13

1. Isolation - populations of species are separated due to physical barrier
2. As environment is different on each side, each population shows genetic variation bc have wide range of alleles due to natural selection operating differently on population
3. In each population, individuals with characteristics that
   make them better adapted to their environment = have better chance of survival (so breed successfully)
4. Alleles that control beneficial characteristics are passed on to next generation
5. Populations becomes so different that successful interbreeding is no longer possible = are separate species

Question 14

What is extinction?

Answer 14

When no individuals of a species remain

Question 15

Name 5 possible reasons for extinction

Answer 15

• Environment changes too quickly
• Catastrophic event happens that kills them all
• New disease kills them all
• A new predator kills them all
• Can’t complete with another (new) species for food

Question 16

What are fossils?

Answer 16

Remains of dead plants and animals

Question 17

How can fossils form? Name 3 ways

Answer 17

• From gradual replacement by minerals
• From casts and impressions
• From preservation in places where no decay happens

Question 18

Give an example of fossils that created from gradual replacement by minerals

Answer 18

E.g. skeletons that have been replaced by minerals to become rock

Question 19

Give an example of fossils that created from casts and impressions

Answer 19

E.g. outline of paw prints, burrows, etc

Question 20

Give an example of fossils that created from preservation in places where no decay happens

Answer 20

E.g. preserved in ice

Question 21

Why is the fossil record incomplete?

Answer 21

Geological activity & because some organisms don’t leave fossils

Question 22

What did Lamark argue?

Answer 22

That the changes that an organism acquires during its lifetime will be passed on to its offspring

Question 23

Explain what Lamark thought

Answer 23

Thought that if a characteristic was used a lot by an organism = it would be more developed during its lifetime and organism’s offspring would inherit the acquired characteristic

Question 24

Define genetic variation

Answer 24

Different characteristics as a result of mutation or reproduction

Question 25

Define environmental variation

Answer 25

Different characteristics caused by an organism’s environment (acquired characteristics)

Question 26

What is HOMO in homo sapiens called?

Answer 26

Genus

Question 27

What is SAPIENS in homo sapiens called?

Answer 27

Species

Question 28

What causes variation?

Answer 28

1. Mutation

2. Sexual reproduction