Chapter 18: Variation and Selection Flashcards
What is Variation?
Variation is defined as the differences between individuals of the same species
What is Phenotypic Variaton?
Phenotypic variation is defined as the differences in features of individuals of the same species
What is continuous Variation?
Is when there are very small degrees of difference for a particular characteristic between individuals and they are arranged in order and can usually be measured on a scale (e.g. heigh, mass, finger length
What is Discontinuous Variation?
Discontinuous variation is when there is a distinct difference for a characteristic in individuals. e.g. blood group, sex. tongue rolling
What are examples of genetic variation?
Blood group, eye colour, gender, ability to roll tongue, whether ear lobes are free or fized
What’s the meaning and what factors does environmental variation include?
Environmental simply means outside the body. and so can include factors like climate, diet, culture, lifestyle and accidents during lifetime.Examples include:
-An accident may lead to scarring on the body
- Eating too much and not leading an active lifestyle will cause weight gain
- Being raised in a certain country will cause you to speak a certain language with a
certain accent
o A plant in the shade of a big tree will grow taller to reach more light
What is discontinuous variation mostly caused by?
Usually caused by genetic variation alone.
How do genes and the environment correlate?
Although genes decide what characteristics we inherit, the surrounding environment will affect how these inherited characteristics develop
Wat are mutations?
Mutations are random genetic changes
How is a survival advantage given to an individual? give an example
Rarely, do mutations lead to the development of new alleles and so new phenotypes that have a small effect on Organisms. occasionally that new allele gives the individual a survival advantage over other members of the species.
for example, a bird develops a mutation to a change in feather colours that attracts more birds of the opposite sex, leading the bird to breed more and have more chances of passing the mutated phenotype to the next generation.
whats a harmful and dramatic change that mutations have done to humans?
Sometimes mutations can lead to harmful and dramatic effects on the body, for examle sickle cell anemia
What is an adaptive feature?
An adapted feature is an inherited feature that helps an organism reproduce and survive in its environment. It is a functional feature that increases the organism’s fitness
What is fitness?
Fitness is the probability of the ability of an organism to survive and reproduce in the anviroment in which it is found.
What is meant b the survival of the fittest?
a term used to explain why some organisms succeed in the competitive struggle for survival against other members of the population
Define Evolution:
Evolution is defined as the change in adaptive features over time of a population as a result of natural selection.
