More Babies Than Space
What does it mean when a species has the potential to increase in number?
More offspring are produced than can survive.
What is genetic variation?
Differences in traits among individuals of the same species.
What is competition in an evolutionary context?
The struggle among organisms for limited resources.
What does “survival of the fittest” mean in biology?
Individuals best adapted to their environment survive and reproduce.
What is natural selection?
The process by which organisms with favorable traits survive and reproduce more successfully.
Why do most organisms produce many offspring?
To increase the chance that some will survive.
Name one source of genetic variation.
Mutations or sexual reproduction.
Name one resource organisms commonly compete for.
Food, water, space, or mates.
What is fitness?
An organism’s ability to survive and reproduce.
How many main factors contribute to evolution by natural selection in this standard?
Four
How does overproduction of offspring contribute to evolution?
It leads to competition because not all offspring can survive.
Why is genetic variation necessary for evolution to occur?
Without variation, all individuals would respond the same to environmental changes.
How does competition influence which individuals survive?
Individuals with advantageous traits are more likely to obtain resources.
Why doesn’t being the strongest always mean highest fitness?
Fitness depends on environmental conditions and reproductive success.
Why must all four factors be present for evolution to occur?
Each factor plays a role in changing trait frequencies over time.
Why doesn’t population size grow endlessly if organisms produce many offspring?
Limited resources prevent all offspring from surviving.
How does sexual reproduction increase variation in a population?
It creates new combinations of genes.
Why does competition occur even within the same species?
Members of the same species need the same resources.
How does reproduction affect which traits increase in a population?
Traits of organisms that reproduce successfully are passed on more often.
Which factor directly causes changes in a population’s traits over generations?
Differential survival and reproduction.
Explain how overproduction of offspring sets the stage for natural selection.
When more individuals are born than can survive, those with advantageous traits are more likely to live and reproduce.
A population with no genetic variation faces a sudden environmental change. Predict the outcome and explain why.
The population is likely to go extinct because no individuals have traits that allow survival.
Explain how competition can change the traits of a population over time.
Traits that improve resource access become more common through differential survival and reproduction.
A trait helps an organism survive but reduces its ability to reproduce. Predict how this trait will change over time.
It will likely decrease because reproduction is required to pass traits on.
Explain how mutation and competition work together to drive evolution.
Mutations create variation, and competition determines which variations are passed on.