10.5 Types of Variation Flashcards
(12 cards)
What is variation?
Differences in characteristics between organisms
What is interspecific variation?
Variation between members of different species
What is intraspecific variation?
Variation between members of a species
What are the genetic causes of variation?
Mutations, alleles, meiosis, sexual reproduction
How do alleles cause variation?
Genes have particular alleles, alleles have different effects
How do mutations cause variation?
Mutations are changes to the DNA sequence which affect genes, which can lead to changes in the proteins (structure, shape, type)
How does meiosis cause variation?
-Gametes are produced by meiosis in organisms that reproduce sexually
-Before the nucleus divides and chromatids of a chromosome separate, the genetic material of the two parents is mixed by independant assortment and crossing over
-Leads to gametes of an offspring showing variation
How does sexual reproduction cause variation?
Offspring produced from 2 individuals inherit genes from each of the parents, so the offspring therefore differs from the parents
What are environmental causes of variation in humans?
Diet, exercise, alcohol, smoking, mutagens
What are environmental causes of variation in plants?
Light intensity, availability of mineral ions, soil pH, competition
What are mutagens?
Agents that cause genetic mutations (e.g chemicals, radiation)
What are the advantages of having a varied population?
Some organisms will have the combination of alleles needed to survive if conditions change adversely
