Biology Unit 1 Cape Mutations and Variation Flashcards
What is variation?
The differences which occur in the characteristics of organisms which belong to the same species or population.
Why is variation important to species?
Differences in adaptations can increase the chances of survival under different or changing environmental conditions.
What are the two main types of variation?
Continuous and Discontinuous Variation
What is continuous variation?
The characteristics in the population show a complete graduation from one extreme to the other.
What are the factors of continuous variation?
-Individuals do not fit into clearly defined groups
-Measurement is usually involved
-There is a range of values from greatest to the least
-This type of variation occurs when the feature being observed is controlled by many genes
-Data may be displayed on a histogram
What is discontinuous variation?
This is the variation within a population of a characteristic that falls into two or more discrete classes .
What are the factors of discontinuous variation?
-Individuals fit into clearly defined groups.
-Measurement of the observation may be involved.
-The environment has little effect. Genes are mainly responsible.
-Does not give normal distribution curves but may be displayed as a bar chart or pie chart.
What causes variation?
Environment and Genetics
What is environmental variation?
This is when the environment has an effect on individuals in a population or species.
What is genetic variation?
Features and characteristics being obtained by parents via genes. Siblings can be different though.
What are the factors leading to Genetic Variation?
-Independent Assortment: The random separation of homologous chromosomes during meiosis which gives different combinations of chromosomes in the gametes.
-Random Fertilization: This is the random fusion of male and female gametes to produce different combinations of chromosomes
-Crossing over: The process during which the homologous chromosomes exchange genetic material in the first stage of meiosis. This leads to new combinations of alleles on chromosomes.
-Mutation: This is a change in the amount, arrangement or structure of the DNA of an organism. If that change is inheritable the results show new traits in a population.
