Genes

Question 1

who proposed the theory of evolution ?

Answer 1

Charles Darwin

Question 2

what island did he travel to , to collect evidence about his theory

Answer 2

the Galápagos

Question 3

what was the peppered moth theory

Answer 3

Tutt suggested that the peppered moths were an example of natural selection. He recognized that the camouflage of the light moth no longer worked in the dark forest. Dark moths live longer in a dark forest, so they had more time to breed. All living things respond to natural selection.

Question 4

which moth was more common 100 years ago

Answer 4

the dark moth was more common due to industrial revolution

Question 5

which moth would be more common nowadays ?

Answer 5

clean moth would be more common as we don’t burn coal anymore making the tree’s cleaner.

Question 6

how many species are there on earth

Answer 6

8.7 million different species, they appeared by evolution

Question 7

what is variation

Answer 7

difference/change in same species

Question 8

what is natural selection

Answer 8

process where species change over time in response to changes in environment , or competition between organisms , in order for species to survive.

Question 9

what year did Charles go to the Galapagos islands

Answer 9

1831

Question 10

how did Charles develop the theory of evolution

Answer 10

he saw that on the galapagos islands the birds all had different beaks to help them eat

Question 11

Name 2facts about the dodo

Answer 11

• Dodos live in islands of Mauritus,

- soldiers found dodos and used them for fresh meat

Question 12

why did the dodo become extinct

Answer 12

over harvesting of the birds , combined with habitat loss and a losing competition and newly introduced animals was too much for dodos to survive

Question 13

why did hawaiian snails get extinct

Answer 13

they usually ate leaves from trees , but due to deforestation these snails lost their food. when eating they reduced fungi on trees , but as snails extinct , fungi grew

Question 14

how did passenger pigeons get extinct

Answer 14

last pigeon died in 1914. they were hunted and weren’t able to breed. this made the population fragile. By shooting them, they completely extinct

Question 15

what is captive breeding ?

Answer 15

captive breeding is when animals are kept in zoo’s to help them breed and keep them healthy to later allow them to go back to freedom.

Question 16

what is a gene bank

Answer 16

a gene bank is when they collect genes to replant them or use them to help return animals

Question 17

what are chromosomes

Answer 17

chromosomes are packages of DNA ( Deoxyribonucleic acid ) The chromosomes are found in the nucleus of each cell. Human body cells each contain 23 pairs of chromosomes, half of which are from each parent. So, human gametes (eggs and sperm) each contain 23 chromosomes. When an egg is fertilised by a sperm, it becomes a cell with 23 pairs of chromosomes.

Question 18

what does DNA do ?

Answer 18

DNA decides everything about us, from the colour of our to how we digest food and how tall we grow, so it is very important to protect it from damage. Each section of a chromosomes that controls one of our features is called a gene

Question 19

what can mutations cause?

Answer 19

• mutations to our DNA can cause cancer

- mutations that we pass onto our children can cause inherited diseases such as cystic fibrosis or sickle cell anaemia

Question 20

who discovered the structure of the DNA

Answer 20

Rosalind Franklin , Maurice Wilkins ,James Watson and Francis crick discovered the double-helix structure of DNA, which formed the basis for modern biotechnology

Question 21

what does mutation mean

Answer 21

A mutation is a change in the structure of a gene, the unit of heredity. Genes are made of deoxyribonucleic acid (DNA)

Question 22

what is an allele

Answer 22

different versions of a gene

Question 23

what is a dominant allele

Answer 23

an allele that will always how through in our feature

Question 24

what is a recessive allele

Answer 24

an allele that will only show through if we inherit it from both parents.

Question 25

name some advantages of genetic modification

Answer 25

• quicker than selective breeding e.g genes from jellyfish have been used to produce crops that glow in the dark when lacking water
• allows scientist to learn about diseases e.g. mice have been modified to model human diseases including Alzheimer’s, cancer and diabetes.
• improved resistance to insect attack e.g. a taste gene in tomatoes has been charged so that ants wouldn’t eat them.

Question 26

name some disadvantages of genetic modification

Answer 26

• insects may become pesticide - resistant if constantly eat pesticide forming plants
• may be bad for human health
• people may use it to ‘design’ children with particular characteristics such as high intelligence or good looks

Question 27

what is genetic modification

Answer 27

a technique in which scientists insert foreign genes into organisms to change their characteristics.

Question 28

what does extinct mean

Answer 28

when no more individuals of a species remain anywhere in the world

Question 29

what is mutation

Answer 29

change to DNA that can cause disease

Question 30

what is a gene

Answer 30

section of DNA that contains the information for a characteristic

Question 31

what is natural selection

Answer 31

process by which the organisms with the characteristics that are most suited to environment survive and reproduce passing on their genes

Question 32

what is DNA

Answer 32

chemical that contains all the information needed to make an organism