B7

Question 1

Variation?

Answer 1

Differences in the characteristics of individuals in a population

Question 2

3 causes of variation?

Answer 2

alleles - genetic e.g. hair and eye colour

Environment - language

a mix of both - height

Question 3

Mutation?

Answer 3

random changes in dna

Question 4

What can very rarely happen due to mutation?

Answer 4

a new phenotype leading to a change in species

Question 5

what have all species of living things evolved from?

Answer 5

Simple life forms e.g. single cells
Called natural selection

Question 6

what is the process of natural selection?

Answer 6

for example, rabbits that have inherited the allure for thicker are more likely to survive in the cold temperature than rabbits with thinner fur which means they are more likely to go on to reproduce and they’re offspring could inherit the alleles for thicker fur and they are more likely to survive and reproduce

Question 7

How do two separate species occur?

Answer 7

Sometimes two populations of one species can become so different in a phenotype that they can no longer into breed to produce fertile offspring

Question 8

How did dogs occur and why?

Answer 8

thousands of years ago humans realise that wolves actually very useful animals as they provide protection, warmth and company. so humans took wolves and using the process of selective breeding over thousands of years created dogs. 

Question 9

why have certain plants been selectively bred?

Answer 9

To produce large and unusual flowers

Question 10

Why have domestic dogs been selectively bred?

Answer 10

To have a gentle nature

Question 11

Why have food crops such as wheat been selectively bred?

Answer 11

To be resistant to disease

Question 12

why have animals such as cows been selectively bred?

Answer 12

To produce more meat or milk

Question 13

how is selective breeding carried out?

Answer 13

For example, if scientist wanted to breed large cows for meat, first we select the largest male and female, we then breed these together to produce offspring. We continue doing this over many generations until all the offspring are large.

Question 14

what is a problem with selective breeding?

Answer 14

If we breed together closely related animals or plants, then we can get inbreeding

Question 15

What could inbreeding lead to?

Answer 15

Disease or inherited defects

Question 16

Evolution?

Answer 16

the change in the inherited characteristics of a population over time through natural selection

Question 17

what happens in genetic engineering?

Answer 17

genes from one organism, e.g. humans I’ll cut out and transferred to cells of a different organism e.g. bacteria

The genome of the bacteria is modified and now includes a human gene

Question 18

what is an example of genetic engineering?

Answer 18

For example insulin, which is a hormone involved in blood glucose regulation in humans. bacteria have been genetically modified to contain the human insulin gene and now these bacteria produce human insulin 

Question 19

Another example of genetic engineering for plants?

Answer 19

we can also transfer genes into plants to produce genetically modified crops, which produce a greater yield than normal crops. we can also make them resistant to disease or insect attack.

Question 20

2 possible problems with genetically modified crops?

Answer 20

could they be harmful to insects or wild flowers?

could they be unsafe to eat?

Question 21

gene therapy?

Answer 21

genetic modification is currently being explored as a way to treat inherited disorders in humans

Question 22

steps of genetic engineering?

Answer 22

1) identify the gene that we want to transfer

2) then use ends arms to isolate the gene

3) transfer the gene into a plasmid or virus

4) the desired gene is transferred into the cells of the target organism

Question 23

why do we always transfer the gene at an early stage in the organisms development?

Answer 23

to make sure that all of the cells receive the transferred gene so that the organism develops with the characteristic that we want

Question 24

how do fossils provide really good evidence for evolution?

Answer 24

because they are the remains of organisms from millions of years ago which are found in rocks

Question 25

3 ways that fossils are formed?

Answer 25

1) fossils can form when parts of organisms have not decayed e.g. if temp is too cold or not enough oxygen

2) they can form even if an organism decays parts of the organism are slowly replaced by minerals during the decay process

3) fossils can be the preserved traces of organisms e.g. animals leave footprints

Question 26

what do fossils show?

Answer 26

A huge number of species have become extinct 

Question 27

3 ways that species can become extinct?

Answer 27

A catastrophic event e.g. asteroid astroid

when the environment changes e.g. weather

predators killing them

Question 28

How quickly can bacteria reproduce?

Answer 28

every 30 mins

Question 29

What is the result of bacteria being able to reproduce at such a fast rate?

Answer 29

They can evolve rapidly

Question 30

what do antibiotics do?

Answer 30

Kill bacteria, which is why they are now used in medicines

Question 31

3 ways to reduce antibiotic resistance?

Answer 31

doctors should not prescribe antibiotics inappropriately e.g. not for viruses

Patients need to make sure they complete their course of antibiotics to make sure that all bacteria is killed

restrict the amount of antibiotics used in farming

Question 32

what are the two kingdoms that living organisms were divided into?

Answer 32

Animal kingdom
Plant kingdom

Question 33

What are the smaller categories in each kingdom?

Answer 33

Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 34

How to remember the smaller categories of a kingdom

Answer 34

King Phillip came over for good soup

Question 35

What is the binomial system?

Answer 35

All species are named from their ‘genus’ and their ‘species’
e.g. Zebra has the name Equus quagga

Question 36

what are archae?

Answer 36

primitive bacteria and are found in extreme conditions such as hot springs

Question 37

what is true bacteria?

Answer 37

The kind that lives in the human digestive system

Question 38

what is eukaryota?

Answer 38

animals, plants and fungi

Question 39

Why do scientist use evolutionary trees?

Answer 39

To show how closely related organisms are to each other