Variation and Evololution

Question 1

Define Species

Answer 1

A group of organisms that can successfully interbreed

Question 2

Define mutation and name 2 causes

Answer 2

Any change is the amount or structure of DNA in a cell

Causes:
Carcinogen e.g cigarette smoke
Radiation

Question 3

Define Variation and give its causes

Answer 3

Variation means there are differences between individuals in a species

Causes:
Sexual Reproduction
Mutations

Question 4

Define Evolution

Answer 4

The gradual change over a period of time in the characteristics of a species so that a new species forms

Question 5

Outline the theory of natural selection

Answer 5

Within a population

As time passes resources become scarce and competition occurs between individuals

The individuals that have the best characteristics and best adapt to their environment the best become the dominant type within the species

Survival of the fittest

This is known as natural selection where individuals best adapted to their environment are selected to represent that species

Question 6

Outline the theory of Evolution

Answer 6

Overtime individuals of a species will move to a different environment where they will evolve and change in order to survive in the new environment

When the genetic difference becomes so great between between the 2 populations they can no longer interbreed, this is when a new species is formed

Question 7

What evidence is there of evolution

Answer 7

Fossil Evidence

Comparative anatomy

Comparative embryology

Question 8

Define Genetic Engineering

Answer 8

Process where humans change the genetic make-up of an organism

Question 9

Outline Genetic Engineering in Plants, animals and microorganisms (bacteria)

Answer 9

Plant: In wheat and barley genes from bacteria are added to the plants so they can survive certain herbicides

Animal: Haemophiliacs cannot produce a certain blood clotting agent. The gene for this factor was inserted into sheep which then produce the clotting factor in their milk

Bacteria: Human growth hormone is inserted into bacteria and large colonies of these bacteria are grown in a bio-reactor, hormone is extracted from the bacteria after

Question 10

Outline the stages in Genetic Engineering

Answer 10

ICITE
1. Isolation: Plasmids are taken from bacteria and DNA taken from human cells

2. Cutting: The same restriction enzyme is used to cut the plasmids and also to cut DNA on either side of the gene
3. Insertion: In insertion the gene ends link up with the cut ends of the plasmid (ligase needed)
4. Transformation: The plasmid that contains human gene is put back into the bacterium
5. Expression: Bacteria now makes Growth Hormone (placed in bioreactor)

Question 11

What is the role of Ligase and Restriction Enzymes

Answer 11

Ligase: Joins DNA together

Restriction Enzymes: Cuts DNA