5.2 Natural selection Flashcards
What is necessary for natural selection to occur within a species?
Variation among members of the same species is essential for natural selection. This variation is the raw material upon which natural selection works.
What causes variation between individuals in a species?
Variation is caused by mutations, meiosis, and sexual reproduction. These processes introduce genetic diversity by altering DNA sequences, shuffling alleles during gamete formation, and combining genes from two parents, respectively.
What are adaptations?
Adaptations are characteristics that make an individual better suited to its environment and way of life, enhancing its survival and reproduction.
Why do species tend to produce more offspring than the environment can support?
Species overproduce offspring to ensure that some will survive environmental pressures and predators. This leads to competition, where only the best-adapted individuals survive to reproduce.
How do adaptations affect an individual’s survival and reproduction?
Individuals better adapted to their environment tend to survive longer and produce more offspring. This selective survival and reproduction process ensures that advantageous traits are passed on to future generations.
What happens to the traits of individuals that reproduce?
Traits of reproducing individuals are passed on to their offspring, contributing to the genetic makeup of future generations.
How does natural selection affect the frequency of traits within a species?
Natural selection increases the frequency of characteristics that make individuals better adapted to their environment and decreases the frequency of less advantageous characteristics, leading to evolutionary changes within the species.
How did the beaks of finches on Daphne Major evolve?
The beaks of finches on Daphne Major evolved through natural selection, where changes in food availability due to environmental conditions led to a preferential survival of birds with beak sizes and shapes best suited to the available food sources.
How does antibiotic resistance evolve in bacteria?
Antibiotic resistance evolves through natural selection. Bacteria with genetic mutations that confer resistance to antibiotics are more likely to survive antibiotic treatments, reproduce, and pass these resistance genes to their offspring or spread them through plasmids, increasing the frequency of resistance traits in bacterial populations.
