Variation and Inheritance Flashcards
Variation…
differences in characteristics between different members of a population
e.g., hair colour, eye colour, height and blood group.
Inherited…
characteristics that are passed on from parent to offspring
characteristics are determined by the DNA/genes that were present in the sperm and egg cells from the parents.
Environmental factor…
something in the environment that an organism lives in that can affect their characteristics
you can learn and control it
e.g., the amount of sunlight a person is exposed to is an environmental factor that can affect their skin colour
DNA… (deoxyribonucleic acid)
DNA is found in the nucleus of every cell
genetic information that is inherited from parents and determines inherited characteristics
Gene…
a section of DNA that codes for a particular characteristic, such as eye colour
how variation can be inherited or caused by environmental factors…
Some variation is passed on from parents to offspring, via genes during reproduction.
This is inherited variation.
Some variation is the result of differences in the surroundings, or what an individual does.
This is called environmental variation.
this is what causes variation within members of a group
Selective breeding…
Can be done with plants or animals from the opposite sex/gender
1) a person selects two individuals with desirable characteristics to breed together
2) the offspring with the best characteristics can be selected to breed again
3) Over time, the plant/animal will change so that it has the characteristics that the breeder wanted.
e.g., all modern dogs were originally bred from wolves. Over time selective breeding has produced many different breeds of dog all with very different characteristics
Natural Selection…
a mechanism of evolution
the process through which populations of living organisms adapt and change
1) an individual that is well suited to its environment is more likely to survive and reproduce
2) over time characteristics that help an organism to survive are passed on from parent to offspring and become more common/more exaggerated in the population
3) less favourable characteristics become less frequent and soon become extinct (wiped away)
4) over many generations the species will evolve to become better adapted (suited) to the environment it lives in.
