Topic 4 - Natural Selection And GM Flashcards Preview

Biology GCSE > Topic 4 - Natural Selection And GM > Flashcards

Flashcards in Topic 4 - Natural Selection And GM Deck (42):
1

Natural selection

Environment selects which individuals of a species pass on alleles depending on what variation reproduces in the environment

2

Evidence of evolution to humans

Pentadactyl structure (five fingered limb) shared by many vertebrates

3

Old classification system

5 kingdoms

4

5 kingdoms

Plants
Animals
Fungi
Protists
Prokaryotes

5

New classification system

3 domain system

6

3 domain system

Eubacteria (prokaryote)
Archea (prokaryotes mainly in warm and salty conditions)
Eukaryota (plants, animals, fungi, protista)

7

Order of human species

Ardi
Lucy
Homo habilis
Homo erectus
Homo sapiens

8

Ardi characteristics

Tree climber
Walked upright

9

Lucy characteristics

Walked upright
Face ape-like

10

Homo habilis characteristics

Flat face like humans
Used simple stone tools

11

Homo erectus characteristics

Long distance walker
Strongly built

12

Homo sapiens characteristics

Uses complex tools

13

Selective breeding definition

When plants (maybe animals) are bred together to inherit desired characteristics

14

What does selective breeding produce

New breeds of animals and varieties of plants

15

Reasons for selective breeding

Disease resistance
Increase yield/size
Better to cope with environment
Faster growth
Flavour

16

Disadvantages of selective breeding

Less genetic diversity
Genetic defects
Less desirable characteristics
Offspring may not inherit
Little genetic variation can result in easy spread of disease

17

Genetic engineering definition

Changing genome of organism by introducing new genes to create genetically modified organisms

18

How genetic engineering works

1) Gene cut out of chromosome using enzymes
2) Gene inserted into chromosome in nucleus of different organism

19

Genome definition

DNA

20

GM crops

Plants genetically modified so they have new characteristics

21

What is a vector

Anything that carries gene into a cell eg plasmid

22

Tissue culture

Using cell cultures to make many identical copies of an organism

23

Example of how tissue culture is useful

To test drugs on cell cultures to see effects

24

Why is agar jelly used in tissue culture

Contains nutrients to encourage growth

25

Advantages of animal cell cultures

- test effect of drugs
- produce important proteins eg antibodies

26

Advantages of plant cell cultures

- Produce many clones of GM plants

27

Insulin step 1

Restriction enzymes cut DNA out

28

Insulin step 2

Unpaired bases left at each end called sticky ends

29

Insulin step 3

Restriction enzymes cut open plasmid (bacterial DNA) which also have sticky ends

30

Insulin step 4

Bases with sticky ends mean insulin DNA can be placed in plasmids

31

Insulin step 5

Enzyme DNA ligase link DNA into plasmid

32

Insulin step 6

Plasmid places back into bacteria to divide rapidly

33

What are Bt plants

Contains bacillus thuringiensis which produces a chemical which is poisonous to pest insects (known as Bt toxin)

34

Example of insect resistant plant

Bt plants

35

Advantages of GM plants

-Increase crop yield
-Better for biodiversity as less chemicals to kill harmless insects

36

Disadvantages of Gm crops

-Seed from these plants is more expensive
-insects can become resistant to toxins
-gene may transfer to wild plants through pollination

37

What solutions are there to providing food for growing populations

Fertilisers and biological control

38

Advantages of fertilisers

-contain nutrients to encourage growth of cell
-increase crop yield
-good way to use animal waste

39

Disadvantages of fertilisers

-Can cause eutrophication
-Expensive to make if artificial
-Artificial fertilisers reduce soul biodiversity

40

What is biological control

When a natural predator, parasite or disease of the pest is used to keep population low

41

Advantages of biological control

-Pest cannot become resistant
-Control agent can be specific to pest
-Doesn’t leave harmful resedues or kill useful organisms like chemicals

42

Disadvantages of biological control

-Doesn’t get rid of pest completely
-Control agent may become pest itself