Test 2 Flashcards
(22 cards)
What is continuous variation?
A type of variation where characteristics vary in a smooth and gradual way, e.g., height and length.
What type of graph is used for continuous variation?
Histogram.
What is discontinuous variation?
A type of variation with distinct categories, e.g., tongue rolling and hand dominance.
What type of graph is used for discontinuous variation?
Bar chart.
What is genetic variation caused by?
Mutations and sexual reproduction.
What is a mutation?
A random change in the number of chromosomes or the structure of a gene.
How does sexual reproduction contribute to variation?
It produces different combinations of alleles, leading to different phenotypes.
What is environmental variation?
Differences in phenotype caused by environmental factors, e.g., diet affecting height.
Give an example of a trait affected by both genes and environment.
Human height.
What is natural selection?
A process where organisms with the best-adapted traits survive and reproduce, passing on their genes.
What is meant by differential survival?
Some individuals survive better than others due to advantageous traits.
How does variation lead to evolution?
Variation provides a range of traits; the best-adapted survive and reproduce, leading to gradual changes in species over time.
What role does competition play in natural selection?
Organisms compete for resources; only the best-adapted survive and reproduce.
What is antibiotic resistance an example of?
Natural selection in bacteria – resistant bacteria survive and reproduce.
What is evolution?
The gradual change in species over time due to natural selection.
What can long-term evolution result in?
The formation of new species.
What is extinction?
The complete disappearance of a species.
What causes extinction?
Failure to adapt to environmental changes.
What is selective breeding?
When humans breed plants or animals for specific desirable traits.
Give examples of traits selected in selective breeding.
Appearance, increased yield, food quality, disease resistance.
How is selective breeding carried out?
Individuals with desirable traits are chosen and bred; this is repeated over generations.
What is the result of many generations of selective breeding?
Offspring consistently show the desired characteristics.
