natural selection & genetic modification

Question 1

What is evolution?

Answer 1

Change in frequency of a phenotype in a population over many generations.

Question 2

What was Darwin’s theory?

Answer 2

• individuals in a species show a wide range of variation due to differences in genes.
• those with characteristics most suited to environment have a higher chance of survival & more chances to reproduce.
• these characteristics are passed down to their offspring at a higher rate than those with less suited ones.
• over many generations, these suited characteristics become more common in the population & the species evolves.

Question 3

What are antibiotics?

Answer 3

Chemical substances that disrupt bacterial cells’ function and prevent them from reproducing.

Question 4

What are the 3 hominid fossils?

Answer 4

ardi, lucy and turkana boy.

Question 5

Summarise ardi.

Answer 5

• chimp sized brain
• hands not used for walking
• longer arms, shorter legs
• longer big toe for climbing
• leg structure suggests he walked upright

Question 6

Summarise Lucy.

Answer 6

• larger brain than ardi
• legs and arms more in proportion
• arched feet
• walked upright

Question 7

Summarise turkana boy.

Answer 7

• human sized brain
• shorter arms, longer legs
• pelvis more human-like
• more human like feet than lucy
• walked upright

Question 8

How did stone tools develop?

Answer 8

Stone tools gradually became more complex over time as their brains were also evolving larger and larger.

Question 9

How can you date stone tools?

Answer 9

• by looking at the structural features
• by using stratigraphy
• by using carbon-14 dating

Question 10

What are the 5 kingdoms?

Answer 10

Prokaryotes, protists, fungi, plants, animals

Question 11

What are the 3 domains?

Why were they created?

Answer 11

Archaea, bacteria, eukaryota.

Due to evidence from genetic analysis.

Question 12

What is selective breeding?

Answer 12

To select individuals with desirable characteristics and breed them together, repeating for many generations.

Question 13

What animals are commonly selectively bred and what for?

Answer 13

• cows, goats and sheep for milk or meat
• chickens laying large eggs
• domestic dogs with a gentle nature
• horses that are fast

Question 14

Why are plants selectively bred?

Answer 14

• disease resistance in food crops
• hardiness to weather conditions
• better tasting fruits
• large or unusual flowers

Question 15

Selective breeding can lead to… occurring when… resulting in…
leading to…

Answer 15

Inbreeding

Animals or plants which are closely related are bred

A gene pool reduction

Harmful genetic defects and vulnerability to new diseases

Question 16

What is genetic engineering?

Answer 16

Modifying genome of an organism to introduce desirable characteristics by removing, altering or inserting genes.

Question 17

Explain the process of genetic engineering.

Answer 17

1. restriction enzymes used to isolate required gene, leaving it with ‘sticky ends’
2. bacterial plasmid cut by same restrictive enzyme leaving it with corresponding sticky ends
3. plasmid & isolated gene joined together by dna ligase enzyme
4. genetically engineered plasmid inserted into a bacterial cell