Darwin's Theory of Evolution

Flashcards on Darwin's Theory of Evolution

What does the term 'biological diversity' refer to?

The variety of living things that inhabit our planet.

What are the questions that are asked by evolutionary biologists?

Why do these organisms live where they do? How did these organisms arise? Which organisms are related to one another? What adaptations allow an organism to live in a particular place? How do organisms change over time?

What are the criteria for something to be considered a Scientific Theory?

An explanation that is based on observation, experimentation, and reasoning. It is supported by a large quantity of evidence and does not conflict with existing experimental results.

What does evolution mean?

Change over time; the process by which modern organisms have descended from ancient organisms. A heritable change in the characteristics within a population from one generation to the next.

Who contributed more to our understanding of evolution than any other individual?

Charles Darwin

When was Charles Darwin born?

February 12, 1809

What was the name of Darwin's grandfather and what did he do?

Erasmus Darwin wrote a book in 1794 called 'Zoonomia' in which he discussed how one species could 'transmute' into another.

What job was Darwin offered before he could take a job as a cleric?

He was offered a job as a 'naturalist' on a voyage around the world on the HMS Beagle.

What occurred in 1835 that influenced Darwin's developing theory on how life changes?

The HMS Beagle made a 5-week stop in the Galapagos Islands.

Why was Darwin conflicted about publishing his theories?

He knew they conflicted with Christian teachings and decided to gather more evidence before going public.

What was the title of Darwin's book?

"On the Origin of Species by Means of Natural Selection."

What is the term for characteristics of organisms that enhance their survival and reproduction in specific environments?

Adaptations.

What is a fossil?

The preserved remains of an ancient organism.

What did Darwin note about the Galapagos Islands?

The cluster of islands is close together, but they have very different climates.

What did Darwin hypothesize about animals living on different islands?

He began to hypothesize that separate species evolved from ancestral species after becoming isolated from one another.

What is 'catastrophism'?

The principle that events in the past occurred suddenly and were caused by different mechanisms than those operating today. Catastrophes in the past (such as floods or erupting volcanoes) were responsible for destroying certain species.

What is the name of the scientist considered 'the Father of Geology'?

James Hutton.

What is 'uniformitarianism'?

The mechanisms of change are uniform over time. The same geologic forces that were active in the past are still operating today.

Who proposed the 'Theory of Acquired Characteristics'?

Jean-Baptiste Lamarck.

What is the 'stuggle for existence'?

Members of a species compete for food, water, living space, and other resources. Competition and certain favorable characteristics determine which organisms live to reproductive age.

What is the name of the term for an organism's ability to survive and reproduce in its specific environment?

Fitness

Natural Selection:

The process in which individuals with certain favorable inherited traits leave more offspring than individuals with other traits. Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase the "fitness" of a species to its environment.

What is 'Common Descent'?

The principle that all living things are derived from common ancestors.

Define 'Artificial Selection'

Variations exist in plants and animals. By selective breeding, humans select the variations they find to be most useful.

If individuals don't evolve, what does?

A population evolves over time.

What is 'absolute age'?

The actual age of the fossil given in years. It is determined through radioactive dating processes.

What are 'transitional fossils'?

Have features and characteristics that are intermediate between ancient ancestors and their later descendants.

What is 'biogeography'?

The study of the locations of organisms around the world. It refers to the distribution of plants and animals in the various regions of the world.

What are 'homologous structures'?

Body parts that are similar in structure but are different in function.

What are 'vestigal organs'?

Structures that seem to be "left over" from a previous ancestor and seem to serve no purpose in the living organism. Vestigial structures are historical remnants of structures that had important functions in ancestors.

What is 'Embryology'?

The study of embryos and their development. Many embryos of organisms of different species look very similar in their early stages of development.

What is signified by all spieces of life having the same basic genetic machinery of DNA and RNA?

That scientists also observe similarities among organisms at the molecular level.

What is 'selection pressure'?

How the pattern and speed of evolution depends on the changing requirements of the environment.

Gradual extinctions

occur due to natural selection.

What happens during a mass extinction?

Species become extinct due to the environmental collapse that is occurring around them, rather than the inability to compete for resources.

What is 'adaptive radiation'?

The sudden appearance of many new species when organisms move into unoccupied habitats and niches.

What is 'convergent evolution'?

The process by which different species evolve similar traits. These organisms face similar environmental demands and will often develop similar structures to meet the demands of the environment.

What is 'Divergent Evolution'?

Closely related species become more and more dissimilar; The descendants of a single ancestor diversify into species that each fit different parts of the environment.

What is 'coevolution'?

The process by which two species evolve in response to changes in each other.

What is 'punctuated equilibrium'?

A term used to describe a pattern of long, stable periods interrupted by brief periods of more rapid change.