Inheritance and Variation 2- Paper 2 Flashcards
Genes determine the phenotype of an organism ? true or false?
False ? the environment also plays a role.
What is variation within a population?
Differences in the characteristics of individuals in a population.
State three causes of variation in a population.
- Genes
- The environment
- A combination of both
Within a population, there is normally very little genetic variation ? true or false?
False ? just look around you at humans
What causes variation within a population?
Mutations.
What is evolution?
A change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.
True or false ? does the theory of evolution by natural selection state that all living things evolved from simple life forms more than three billion years ago?
True.
Would the best organism within a species to survive and reproduce be:
a) the strongest?
b) the one which reproduces the fastest?
c) the best adapted to the environment?
c)
Define ‘species’.
Organisms that can interbreed to produce fertile offspring.
Define ‘natural selection’.
The process by which evolution takes place - Nature chooses those those with favourable characteristics (best suited to environment) to survive and reproduce, passing on their genes
What is selective breeding?
The process by which humans breed plants and animals for particular genetic characteristics.
Name two historic examples of selective breeding.
- Breeding food crops from wild plants
2. Domesticating animals
State four modern examples of selective breeding.
- Disease resistance in food crops
- Animals which produce more meat or milk
- Domestic dogs with a gentle nature
- Large or unusual flowers
State a drawback to selective breeding.
Inbreeding ? some breeds are prone to disease or inherited defects (e.g. some pugs have breathing problems).
What is genetic engineering?
The process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.