natural selection and evidence for evolution Flashcards
(21 cards)
What does Natural Selection mean?
Survival of the Fittest
What causes genetic variation in a population?
Differences in their alleles
How do new alleles arise?
Through mutations
What are alleles?
Versions of genes
What are selection pressures?
Factors that affect an organism’s chance of surviving
What happens to individuals with beneficial characteristics?
They are more likely to survive and reproduce
What is the result of successful breeding of individuals with useful characteristics?
Their alleles are more likely to be passed on to the next generation
What happens to individuals that are less well adapted to their environment?
They are less likely to survive and reproduce
What becomes more common in a population over time?
Beneficial characteristics
What is likely to happen to a species that cannot compete?
It is likely to go extinct
What evidence do bacteria provide for evolution?
They develop random mutations in their DNA
What can mutations in bacteria create?
New alleles that change characteristics
What is a significant advantage for bacteria in relation to antibiotics?
The ability to resist antibiotics
What happens to a resistant bacterium in a treated host?
It survives longer and reproduces more
What leads to the spread of antibiotic resistance in bacteria?
Natural selection
How does antibiotic resistance provide evidence for evolution?
It shows adaptation to an environment with selection pressure
What is a fossil?
Any trace of an animal or plant that lived a long time ago
Where are fossils most commonly found?
In rocks
What does the depth of rock indicate about fossils?
The deeper the rock, the older the fossil
What can be observed by arranging fossils in chronological order?
Gradual changes in organisms
What does the arrangement of fossils provide evidence for?
Evolution and how species have changed over billions of years
