Darwin's Theory of Natural Selection Flashcards

Flashcards reviewing Darwin's theory of natural selection, key concepts, and supporting evidence based on lecture notes.

What is evolution?

The idea that species change over time.

What does evolution lead to?

New species appearing, old species going extinct, populations adapting to new environments.

What did Charles Darwin do?

He traveled around the world on the HMS Beagle and studied plants, animals, fossils, and rocks.

What did Darwin notice in the Galápagos Islands?

Animals that were similar but had small differences depending on the island; finches with different beaks depending on the food available.

What were Darwin's key observations?

1. Variation exists in all populations. 2. More offspring are produced than can survive. 3. Resources are limited. 4. Some individuals are better suited to their environment.

According to Darwin, what is the first inference about survival and reproduction?

Individuals with traits that give them an advantage are more likely to survive and reproduce.

According to Darwin, what is the second inference about favorable traits?

These favorable traits will become more common in the population.

According to Darwin, what is the third inference about species changing over time?

Over many generations, the species will change – this is evolution by natural selection.

What is 'variation' in the context of natural selection?

Individuals in a species are all slightly different due to genes.

What is 'competition' in the context of natural selection?

Organisms compete for survival (food, mates, shelter).

What is 'survival of the fittest' in the context of natural selection?

Those with helpful traits survive longer.

What happens during 'reproduction' in the context of natural selection?

Survivors pass their helpful traits to their offspring.

What happens during 'evolution' in the context of natural selection?

Over many generations, the population changes.

What was Lamarck's old belief about how giraffes got their long necks?

Giraffes stretched their necks to reach high leaves, and this stretched neck was passed on to their babies.

What was Darwin's explanation of how giraffes got their long necks?

Giraffes were born with different neck lengths; during droughts, giraffes with longer necks could reach more food, survive, and have more babies with long neck genes.

Who was Alfred Russel Wallace and what did he contribute to the theory of natural selection?

Wallace saw that animals change based on their environment and sent Darwin a letter describing the same idea – natural selection.

What was the key difference in focus between Darwin and Wallace regarding natural selection?

Darwin focused more on variation and competition, while Wallace focused more on how the environment drives change.

What was Darwin's main idea regarding traits and evolution, and what supported it?

Traits that help survival get passed on through random variation and natural selection; evidenced by genetics and fossils.

What was Lamarck's main idea regarding traits and evolution, and what supported it?

Traits used in life are passed on by using or not using a body part; not supported by modern science.

How does genetics support Darwin's theory of natural selection?

DNA carries instructions for traits; genes are passed from parents to children; mutations are changes in DNA that can create new traits; alleles are different versions of a gene.

What do fossils show as evidence for evolution?

Shows species with traits of two groups.

What does anatomy show as evidence of evolution?

Same bones = common ancestry

What do embryos show as evidence of evolution?

Same early development = common origin

What does DNA show as evidence of evolution?

Close relatives

What does observed evolution show as evidence of evolution?

Evolution in real time

What is an adaptation?

A helpful trait that improves survival.

What is natural selection?

The process where helpful traits become common.

What is fitness?

How well an organism survives and reproduces.

What is a mutation?

A change in DNA that can create variation.

What is variation?

Differences between individuals in a population.

What is a species?

A group of similar organisms that can reproduce.

What does Natural Selection mean?

Better traits = more survival and babies.

What does Variation mean?

All species have differences

What does Adaptation mean?

Trait that helps an organism survive

What does Evolution mean?

A species changing over generations

Who was Wallace?

Helped push Darwin to publish

Who was Lamarck?

Believed acquired traits are passed on (wrong)

What does Modern Genetics confirm?

Proves Darwin was mostly right