Natural Selection etc

Question 1

Explain Darwin’s theory of evolution in terms of natural selection

Answer 1

Most organisms produce more offspring than will survive. Each offspring will show variation. Individuals will compete with each other due to limited resources such as shelter, food, water, space and mates. Those with better adapted variations to the environment are more likely to survive while other will die (survival of the fittest/natural selection). The individual which survive can reproduce and pass on their advantageous variations to their offspring

Question 2

Explain how natural selection brings about evolution

Answer 2

Variations within a population. Mutations cause variations. Those with more desirable features are more likely to breed compared to those with undesirable features as they are less likely to die or be unattractive

Question 3

Evidence to support animal evolution in species

Answer 3

Peppered moths, warfarin rat poisoning, antibiotic resistance

Question 4

Explain antibiotic resistance

Answer 4

Within a population there is variation. Some bacteria are more resistant to antibiotics and will take longer to be killed than others. The less resistant bacteria are killed off by antibiotics and the most resistant bacteria would survive. These resistant bacteria reproduce and pass on their resistant genes, making more resistant bacteria

Question 5

Evidence of human evolution based on fossils

Answer 5

Fossils (1.6). Ardi (4.4mil years, 350cm3 brain, 120cm height), Lucy (3.2mil years, 400cm3 brain, 107cm height), homo habilis, homo erectus, Homo sapiens

Question 6

Evolution def

Answer 6

A gradual change in the characteristics of a species overtime

Question 7

Ways of grouping

Answer 7

Kingdom, phylum, class, order, family, genus, species

Question 8

Binomial name

Answer 8

Genus and species

Question 9

Five kingdom

Answer 9

Plant, animals, Protists, fungi, bacteria

Question 10

Plants features

Answer 10

Cellulose cell wall, multi cellular

Question 11

Animals features

Answer 11

Multicellular, reproduce sexually

Question 12

Bacteria features

Answer 12

No nucleus, unicellular, plasmid DNA, chromosomal DNA

Question 13

Protist features

Answer 13

Unicellular, have a nucleus

Question 14

Fungi features

Answer 14

Multicellular, cell walls made of chitin

Question 15

Heterotrophic

Answer 15

Organisms that can’t make their own food but rely on organic substances instead

Question 16

Autotrophics

Answer 16

Produces its own food from inorganic substances

Question 17

Saprophytic

Answer 17

Live off dead, decomposing organisms

Question 18

Domains

Answer 18

Bacteria, archaea, eukarya

Question 19

Bacteria domains

Answer 19

no nucleus, all genes for something

Question 20

Archaea

Answer 20

no nucleus, some unused DNA present

Question 21

Eukarya domain

Answer 21

Has nucleus, some unused DNA present

Question 22

Selective breeding

Answer 22

When humans reproduce/breed certain organisms together to get desirable features/characteristics

Question 23

Benefits of selective breeding

Answer 23

Grow in different environments, disease resistance, increase yield, nutrition, fast growth

Question 24

Drawbacks of selective breeding

Answer 24

Reduces gene pool

Question 25

Genetic engineering def

Answer 25

A process which involves modifying the genome of an organism to introduce desirable characteristics

Question 26

Genetic engineering stages

Answer 26

DNA is found in the chromosomes in the nucleus. The desirable feature is located. It is cut out using restriction enzymes and has sticky ends. The plasmid vector is cut out using restriction enzymes. The gene is sealed to the plasmid using the enzyme ligase. The plasmid is placed back into the bacterium. The bacteria reproduce asexually and identically and produce the gene

Question 27

Vector

Answer 27

Any DNA that is used to carry another

Question 28

Benefits of genetic engineering in medicine

Answer 28

Can treat diabetes by using insulin genes ...

Question 29

Tissue culture def

Answer 29

The growing of cells or tissues in a medium (liquid) containing nutrients e.g. hormones

Question 30

Advantages of tissue culture

Answer 30

Grows identical cells, grown very quickly in little space, all year round

Question 31

Animal tissue culture use

Answer 31

Used in medical research because you can carry out experiments in isolation e.g. glucose on pancreas. You can look at the effects of a particular substance of a single cell without complications from the whole organism

Question 32

Animal tissue culture process

Answer 32

Take a sample of desired tissue. Cells are separated from each other. Cells are placed in some nutrients so they can grow and multiply. They divide (cells) and multiply (in number). These cells can be extracted and stored.

Question 33

Plant tissue culture process

Answer 33

Choose a plant which best expresses the desired feature. Remove small pieces of tissue from the parent plant (fast-growing root or shoot tips). Grow the tissue in a medium containing nutrients and growth hormones (auxins) under aseptic conditions to prevent growth of microbes that could harm the plants.

Question 34

Biological control

Answer 34

Using living organisms to control pests

Question 35

Why is biological control better than using pesticides?

Answer 35

No cross contamination. No pollution in nearby water sources. Only targets one type of pest. Does not affect any animals that eat the pest (no toxic chemicals) - no harm to the consumer

Question 36

Negatives of using fertilisers

Answer 36

They are used to increase yield. Contain N, K and P. If they are not all absorbed by the plants, they can get into streams and cause water pollution which can lead to the death of organisms that drink the water

Question 37

Aphids

Answer 37

A pest that eats crops and plants. Controlled by parasitic wasps. They inject their eggs in the aphid as the surrogate. The larvae breaks out the aphid, killing it

Question 38

Spider mite

Answer 38

A pest that eats sap, damaging leaf tissue. Controlled with predatory mites. Kill their prey so they die out

Question 39

Weaver ants

Answer 39

Remove pests by placing nests in citrus trees

Question 40

St John's Wart

Answer 40

A weed that grows in grassland, causes animals to become ill. Chrysolina beetles est them to control them

Question 41

Monoculture

Answer 41

An area where only one type of crop is grown

Question 42

Why are plants genetically modified?

Answer 42

disease resistant, drought resistant, increase yield, bigger, more nutrients, pesticide resistant, survive harsh conditions

Question 43

Disadvantages of monoculture

Answer 43

A disease/pest can wipe them all out

Question 44

Bt toxin

Answer 44

Produces a natural insecticide protein (Bacillus thuringiensis)

Question 45

Bt toxin process

Answer 45

Sprayed onto plants as an