B4

Question 1

What is natural selection?

Answer 1

The best adapted organisms live but the worst adapted die out.

Question 2

What could cause natural selection?

Answer 2

Competition for resources, disease and selection pressures.

Question 3

What is evolution?

Answer 3

When an organism changes over millions of years to suit the environment they’re in.

Question 4

What evidence is there that evolution takes place?

Answer 4

Living fossils, “in-between” species, gradual changes, pentadactyl limb, development of tools

Question 5

Who came up with the theory of evolution, and who is the lesser known person who contributed?

Answer 5

Charles Darwin and Alfred Russel Wallace

Question 6

What are the 3 main fossil hominids?

Answer 6

1) Ardipithecus ramidus - “Ardi”
2) Australopithecus afarensis - “Lucy”
3) Homo erectus - found by Richard Leakey

Question 7

What is classification?

Answer 7

Organising living organisms into groups.

Question 8

What is the system that Carl Linnaeus came up with?

Answer 8

Kingdom, Phylum, Class, Order, Family, Genus, Species
(King Prawn Curry or Fat Greasy Sausages)

Question 9

What were the 5 kingdoms?

Answer 9

Animals, plants, fungi, bacteria, protists

Question 10

What did Carl Woese think of this structure?

Answer 10

He thought that there should have been 3 main groups: eukarya, archaea and bacteria.

Question 11

True or false? Selective breeding is when humans breed plants or animals together so that the popular characteristics will stay in the population.

Answer 11

True

Question 12

What is tissue culture?

Answer 12

Growing cells or tissues in a liquid containing nutrients or a solid medium.

Question 13

What methods can you use for tissue culture?

Answer 13

Method 1:
1) A piece of plant is placed in bleach to sterilise it.
2) A small piece is cut off and placed in a sterile nutrient medium to grow.
3) This is treated with hormones so it grows roots and shoots.
4) When it’s large enough, they’re planted into soil or compost.

Method 2:
1) A piece of plant is placed in bleach to sterilise it.
2) Sometimes, only a few cells are cut off and placed in a sterile nutrient medium to grow a callus.
3) The callus is treated with hormones so the plantlets grow roots and shoots.
4) The plantlets are separated and grown in a sterile nutrient medium.
5) When it’s large enough, they’re planted into soil or compost.

Question 14

True or false? A callus is a group of differentiated cells.

Answer 14

False, a callus is a group of UNdifferentiated cells (stem cells).

Question 15

What is genetic engineering?

Answer 15

When you modify an organism’s genome to introduce desirable characteristics using enzymes and vectors.

Question 16

How does genetic engineering work?

Answer 16

1) Find an organism with a useful characteristic.
2) Choose another organism you want to put the useful characteristic into.
3) Find the gene that codes for the useful characteristic.
4) Cut open the DNA of the 2nd organism using a restriction enzyme to create sticky ends.
5) Cut out the useful gene using a restriction enzyme to create sticky ends.
6) Insert the useful gene into the other organism’s DNA and stick the 2 sticky ends together using ligase.

Question 17

What are the benefits of genetic modification?

Answer 17

1) The potential chance to cure incurable diseases.
2) We can genetically modify food to contain more vitamins and minerals in them (e.g. golden rice).

Question 18

What are the potential consequences of genetic modification?

Answer 18

1) It has irreversible effects, so it would be inside the organism permanently.
2) Researchers don’t have much information on the long-term consequences.
3) Eating genetically modified crops could make us sick or even cause cancer.