Variation And Selection Flashcards
Variation is usually caused by differences in ….
🚝 Genetic make up (genotype)
🚝 Environmental factors
What does the process of meiosis help to ensure?
The process of meiosis helps to ensure that each gamete produced by a parent has a different chromosome arrangement.
Give an example of a characteristic that is caused by a combination of genetic and environmental factors?
Height
Height in humans is affected by both genetic and environmental influences: the genotype will determine the potential height that an individual can attain, but they will only grow to that height if there is a good diet and overall good health.
Give an example of a characteristic that is caused by a combination of genetic factors alone?
Eye colour
Eye colour is purely genetic and cannot be affected by an environmental conditions.
What is it continuous variation?
A continuous variation is where there is a gradual change in the characteristic across the population. Height is an example of a continuous variation.
What is a discontinuous variation?
Discontinuous variation is where the population can be divided into discrete groups. Examples include the ability to roll your tongue or your blood-group
What is natural selection?
Natural selection is the process where nature selects the fittest individuals and rejects the less fit ones.
🚝 Within a species there is variation between individuals.
🚝 Some individuals are better adapted to the environment than others.
🚝 These better adapted individuals are more likely to survive. This is the survival of the fittest.
🚝 These individuals are more likely to pass their genes on to the next generation.
What is variation?
Variation is differences in organisms of the same species. Living organisms that belong to the same species vary from each other in ways such as height, weight, eye colour, intelligence and hair type.
What is extinction?
🚝 In organism may be described as been extinct if there are no living examples of it left.
🚝 The fossil record shows that many animals and plants have become extinct through time.
🚝 The most famous examples are the dinosaurs and mammoths.
