Evolution Flashcards

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1
Q

Voyage of the Beagle

A

Charles Darwin (born Feb 12, 1809, in England) set sail in 1831 on the H.M.S Beagle. Made numerous observations, collected and studied specimens/fossils, and discovered patterns of diversity that led him to propose a revolutionary hypothesis about how life changes over time (the theory of evolution).

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2
Q

Ideas that shaped Darwin’s thinking

A

Lots of fossil records much older than what was then believed to be the Earth’s current age.

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3
Q

James Hutton

A

1795 geologist, thought that Earth was very old.

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4
Q

Charles Lyell

A

1831 geologist, thought the processes of shaping the now and the past were the same (erosion, weathering, volcanos).

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5
Q

Jean Baptiste Lamarck

A

Thought living things change over time and species are descended from other species. Lamarck’s theory of evolution dictated that the tendency toward perfection helped with survival (use & disuse) as well as the inheritance of acquired traits. He was wrong because behavior doesn’t affect DNA and he didn’t know how traits were inherited.

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6
Q

Thomas Malthus

A

Thought that unchecked population growth would quickly overpopulate the earth (more births than deaths). Darwin questioned what caused the deaths of so many, and what factors determine which survive and reproduce. Concluded that in nature, all species tended to produce more offspring than they could support.

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7
Q

Galapagos Islands

A

Islands are close together but have very different climates, Darwin was fascinated by the different species of land tortoises and marine iguanas across the islands.

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8
Q

Alfred Russell

A

Darwin worked with Alfred Russell in 1858. Wrote an essay summarizing Darwin’s theory of evolution.

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9
Q

Darwins book

A

Darwin worked on his book for years but was scared to publish it because of religious backlash, but he published “On the Origin of Species by Means of Natural Selection” in 1859.

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10
Q

Artificial Selection

A

Nature provides the variation and humans select the variations they find useful.

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11
Q

Natural selection

A

Nature (the environment) will determine the organism that is the fittest to survive, results in changes in the inherited characteristics of a population, and increase fitness over time.

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12
Q

Struggle for existence

A

The highest fitness species can survive and reproduce in its specific environment, which results from adaptations.

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13
Q

Descent with modification

A

Each living thing has descended with changes from species over time.

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14
Q

Convergent evolution

A

Similar species in similar environments, unrelated species come to resemble each other, e.g placentals and marsupials.

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15
Q

Divergent evolution

A

Two or more species becoming more and more dissimilar.

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16
Q

Analogous structures

A

Structures that serve the same function in different species but evolved independently, e.g bat and butterfly wings.

17
Q

Vestigial organs

A

Organs that serve no useful function in an organism, because their presence doesn’t affect fitness.

18
Q

Homologous body structures

A

Structures that have different mature forms in different organisms but evolved from the same embryonic tissues.

19
Q

Mutagens

A

E.g UV rays and harmful chemicals, causes DNA to mutate.

20
Q

Mutations

A

Usually not advantageous but can be, can cause the organism to die. DNA mutations control evolution, positive mutations are selected by the environment and eventually accumulate throughout generations.

21
Q

How do variations occur

A

When an individual can contribute its alleles to the population’s gene pool, it may increase the frequency of the alleles. Evolution is any change over time in the relative frequencies of the population.

22
Q

Single gene traits

A

Natural selection of non-single gene traits can lead to changes in allele frequencies and thus to evolution.

23
Q

Directional selection

A

Occurs when individuals at one end of the curve have higher fitness than individuals in the middle or other end.

24
Q

Stabilizing selection

A

When individuals near the center of the curve have higher fitness than individuals at either end of the curve (human babies).

25
Q

Disruptive selection

A

When individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle.

26
Q

Speciation

A

The formation of new species, occurs when natural selection and chance change the relative frequencies of alleles in a population.

27
Q

Species

A

A group of organisms that breed with one another and produce fertile offspring.

28
Q

Process of speciation

A

Isolation of gene pools, long-term separation of gene pools, once enough change has occurs the species should no longer be able to reproduce with each other or create fertile offspring.

29
Q

Reproductive isolation

A

When two populations cannot interbreed and produce fertile offspring.

30
Q

Geographic isolation

A

When two populations are reproductively isolated by geographic formations.

31
Q

Behavioral isolation

A

When two populations are capable of interbreeding but have different reproductive strategies that involve behavior, such as courtship rituals.

32
Q

Temporal isolation

A

When two or more species reproduce at different times.

33
Q

Phenotype

A

Physical expression of genotype.

34
Q

Genotype

A

Genetic makeup of an organism.

35
Q

Recessive

A

When the allele can only be expressed when the genotype is homozygous.

36
Q

Dominant

A

When the allele has a stronger expression within the genotype than the other allele.

37
Q

Homozygous

A

An organism in which both copies of a given gene have the same allele.

38
Q

Heterozygous

A

An organism in which the copies of a given gene have different alleles.