Variation Flashcards
Inheritance, Variation, and Evolution (11 cards)
What is variation within a species?
Differences among organisms of the same species
Variation can be due to genetic and environmental factors.
What are the two types of variation?
Genetic variation and environmental variation
These variations explain why organisms may look different even within the same species.
What causes genetic variation?
The combination of genes inherited from both parents
Genes are passed on in sex cells (gametes).
What are genes?
Codes inside cells that control how an organism is made
Genes influence various characteristics.
Can two organisms of the same species be genetically identical?
No, except for identical twins
Genetic variation ensures that most individuals are not identical.
Which characteristics are determined only by genes?
Eye colour, blood group, inherited disorders
Examples include haemophilia and cystic fibrosis.
What is environmental variation?
Differences caused by the environment in which organisms live and grow
Examples include differences in growth due to sunlight or other conditions.
How does the environment affect plant growth?
A plant grown in sunlight is luscious and green, while one in darkness is tall and spindly with yellow leaves
This demonstrates how environmental conditions can influence characteristics.
What do most characteristics depend on?
A mixture of genetic and environmental factors
Examples include body weight, height, and skin colour.
What is the role of mutations in variation?
Mutations are changes in the DNA sequence that can introduce new phenotypes
Most mutations have no effect, but some can lead to significant changes.
What happens if a mutation results in a beneficial phenotype?
It can become common in the species through natural selection
This process occurs if the environment changes and the new phenotype is advantageous.
