evolution

What are mutations and why are they important in evolution?

A mutation is a change in DNA, the hereditary material of life. An organism's DNA affects how it looks, how it behaves, and its physiology. So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation. Without mutation, evolution could not occur.

What constitutes a scientific theory?

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on knowledge that has been repeatedly confirmed through observation and experimentation.

What evidence of evolution did Darwin present?

Comparative anatomy - analogous and homologous structures Variation in species and similarities within Genera Fossil record Biogeography Ability to create variation by man, expectation of similar in nature

What is ultimate proof of Darwin's theory of evolution?

DNA evidence

What is decent with modification?

Descent with modification refers to the passing on of traits from parent organisms to their offspring.

Why is evolution called a theory?

Evolution is called a theory because allthough it has not yet been proven, nobody has found evidence that goes against it. On the other hand, nobody has found evidence that shows that it must exist. Therefore it is a theory.

What pattern did Darwin observe among organisms of the Galapagos and elsewhere?

He collected a bunch of birds that, at plain sight, they looked different. When he had them analyzed by an ornithologists back in England, he learned, much to his surprise, that they were all finches! The reason why they looked different was because these finches adapted very differently in different parts of the island. That "adaptation" led him to postulate his theory of evolution.

Describe what Darwin did on the HMS beagle.

He collected and took notes on species he saw that led to his eventual theory of evolution. For example while in the Galapagos Darwin collected samples of mockingbirds, and later observed that the birds were somewhat different on each island. This made him think that the birds had a common ancestor, but had followed varying evolutionary paths once they were separated.

What was Charles Darwin's Contribution to Science?

He proposed and provided scientific evidence that all species of life have evolved over time from common ancestors through the process he called natural selection.

What might we expect in the gene pool of Nairobi people if we came back 1000 years from now? Why?

Hiv is one of the leading causes of death for them so it acts as an environmental pressure and 1000 years from now the carrier frequency for HIV resistant alleles will increase.

What is a homologous structure?

Homologous structures or organs are those that share a common ancestry or origin

What is artificial selection?

Human intervention in animal or plant reproduction to ensure that certain desirable traits are represented in successive generations.

How did Hutton & Lyell describe geologic change?

Hutton and Lyell helped scientists recognize that earth is many millions of years old, and the processes that that changed earth in the past are the same processes that operate in the present.

What does variation have to do with struggle for existence?

In an environment, variation is important because the most successful organism will be "selected" Then a struggle for existence will take place and the variation that was selected will win.

How is natural variation used in artificial selection?

In artificial selection, nature provides the variation, and humans select the variations that they find useful.

What does common descent mean?

In evolutionary biology, a group of organisms share common descent if they have a common ancestor. There is strong evidence that all living organisms on Earth are descended from a common ancestor

What was Malthus's theory of population growth?

Malthus hypothesized that unchecked population growth would quickly exceed carrying capacity, leading to overpopulation and social problems.

How is artificial selection different from natural selections?

Natural selection appears in nature and has created species. These changes can take millions of years as species compete with each other, allowing some changes to survive and other changes to disappear. Artificial selection is done by humans to intentionally create changes in species, such as the development of dog breeds.

How is natural selection related to a species' fitness?

Natural selection is the way in which a genetic pool changes in response to a selection pressure. Genes which increase a species fitness (that is ability to survive and BREED) under a certain selection pressure become more prominent in the gene pool as they are being passed on more often due their increased breeding.

How does nature select certain traits?

Nature or the environment will select certain traits in animals that are better suited for their environment.

When/how does an organisms become a distinct species?

Often when two species are separated, and put in two different environments they evolve into two different species based on the pressures of their environment. for example: Imagine that we take a population of horses, split them in half and place them in completely different environments. The two species will evolve separate from each other and because the environment is different, the outcome of evolution will be different.

Summarize Darwin's theory of Evolution by Natural Selection.

Only the strongest will survive. Not necessarily the physically stronger animal but the one that is better suited to survive in the current environment. If lions are chasing antelope then the fastest one will survive and live on to reproduce. The slowest will be killed without having the chance to pass on the genes that were not as good as the fastest animal.

What are vestigial organs?

Organs that were once used but not anymore. Example: In the embryo snakes have legs but when they are born, they lose their legs. Those legs are vestigial organs.

According to Lamark, how did species evolve?

Over the course of their lifetime an organism would evolve to best fit its environment. (for example over the course of a giraffes life, Because of always reaching its neck up to get food the giraffes neck would stretch out and its descendents would have those traits.)

What types of animals did humans change via artificial selection?

Pigeons and Dogs are too big examples and often animals who are in agriculture like chickens, cows, pigs are often artificially selected

What did Darwin realize about different life forms, bones, & embryos?

That their are homologous. They structurally are the same but are just used for different purposes.

What did Darwin's travels reveal to him about the number and variety of living species?

That there were lots and lots of different species. He noticed that a lot of the same species were in the same area which lead him to question why God would place them together. If creation was true, than the organisms should be randomly spaced.

What is evolution?

The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

What is a fossil?

The remains or impression of a PREHISTORIC organism preserved in petrified form or as a mold or cast in rock.

What are the similarities and differences between Lamark and Darwin's theory?

There is a big difference between Lamarck and Darwin's theory of evolution. Darwin theorized that all present organisms today came from a few much simpler organisms. Lamarck theorized that bigger and stronger organisms survive while weak ones become extinct.

What is more likely to happen to an organism's genes if they survive?

They will get passed down!

In natural selection, what is being "selected?"

Traits that help the organism to survive better.

What is the "struggle for existence"?

the competition in nature among organisms of a population to maintain themselves in a given environment and to survive to reproduce others of their kind.

Describe natural selection

the process whereby organisms better adapted to their environment tend to survive and produce more offspring.