Darwin's Theory of Evolution

What is artificial selection?

Animal/Plant breeders influence fitness

What is an adaptation?

Any heritable characteristic that increases an organism's ability to survive and reproduce in is environment.

Why was Darwin's recognition about natural variations important?

Because it provided the raw material evolution, even though had no idea how heredity worked or what caused heritable variation.

Why did Darwin name his mechanism for evolution "natural selection?"

Because of its similarities to artificial selection. It is the process by which organisms with variations most suited to their local environment survive and leave more offspring.

Why does natural selection only acted on inherited traits?

Because those are the only characteristics that parents can pass on to their offspring.

How did scientists view variations in animals before Darwin's theory?

Before Darwin, scientists thought variations among individuals in nature were simply minor defects.

How do biologists test for homologous structures?

Biologists test whether structures are homologous by studying anatomical details,.

What are analogous structures?

Body parts that share a common function, but not structure

What is evolution?

Evolution is the process of change over time.

What biogeographical patterns are significant to Darwin's theory?

First, a pattern in which closely related species differentiate in slightly different climates Second, a pattern in which very distantly related species develop similarities in similar environments

What were Lamarck's two hypotheses?

First, that organisms could change during their lifetimes by selectively using or not using various parts of their bodies. (This is true) Second, that individuals could pass these acquired traits on to their offspring, enabling species to change over time. (This is false)

How did Lamarck explain "inheritance of acquired characteristics?"

He believed that all organisms have an inborn urge to become more complex and perfect.

How did Darwin use artificial selection to explain his theory?

He concluded that some of the variations could be passed from parents to offspring and used to improve the species.

What did Darwin mean by "species vary locally?"

He meant that different, yet related, animal species often occupied different habitats within a local area.

What did Lamarck get right?

He recognized that there was a link between an organism's environment and its body structures.

What did Hutton and Lyell conclude about Earth's history?

Hutton and Lyell concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.

How does natural selection explain the extinction of a species?

If local environmental conditions change faster than a species can adapt to those changes, then the species may become extinct.

What is the difference between natural selection and artificial selection?

In natural selection the environment, rather than a farmer or animal breeder, influences fitness.

What did Darwin conclude about the fossils he collected?

It lead him to conclude that species vary over time.

What is Lyell's principal of uniformitarianism?

Lyell believed that the geological processes we see in action today must be the same ones that shaped Earth millions of years ago. (war, disease, and famine)

What was Malthus' view on population growth?

Malthus noted that humans were being born faster than people were dying.

Fitness

Most capable of surviving and reproducing

Was Darwin the first scientist to suggest that characteristics of species could change over time?

No. Jean-Baptist Lamarck, a French naturalist, proposed two hypotheses on the subject during the 18th century.

Why were Lamarck's hypotheses incorrect?

Species want to become more perfect and complex

What are homologous structures?

Structures that are shared by related species

3 Parts of Natural Selection

Struggle for Existence, Variation/Adaptations, and Survival of the Fittest

What is survival of the fittest?

Survival of the fittest means the organism's ability to stay alive as well as to reproduce and pass adaptations on to the next generation.

What was Darwin's book called?

The Origin of Species

What are acquired characteristics?

Traits altered by an individual organisms during its life.

What are vestigial structures?

Vestigial structures are inherited from ancestors, but have lost much or all of their original function

What is biogeography?

Where organisms live now and where they lived in the past.

What three patterns of biodiversity did Darwin note?

(1) Species vary globally, (2) Species vary locally, and (3) Species vary over time.

What was Charles Darwin's contribution to Science?

Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

What role does variation and adaption play?

Darwin hypothesized that some traits are better suited to life in their environments than others. Thus, only the stronger/faster survive.

What did Darwin mean by "species vary globally?"

Darwin meant that different, yet ecologically similar, animal species inhabited separate, but ecologically similar, habitats around the globe.

What is "descent with modification?"

Darwin proposed that living species are descended from common ancestors

What is the struggle for existence?

Darwin's view that if more individuals are produced than can survive, members of a population must compete for food, shelter and other limited necessities of life.