Evolution

Question 1

Voyage of the Beagle

Answer 1

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).

Question 2

Ideas that shaped Darwin’s thinking

Answer 2

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

Question 3

James Hutton

Answer 3

1795 geologist, thought that Earth was very old.

Question 4

Charles Lyell

Answer 4

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

Question 5

Jean Baptiste Lamarck

Answer 5

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.

Question 6

Thomas Malthus

Answer 6

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.

Question 7

Galapagos Islands

Answer 7

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.

Question 8

Alfred Russell

Answer 8

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

Question 9

Darwins book

Answer 9

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.

Question 10

Artificial Selection

Answer 10

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

Question 11

Natural selection

Answer 11

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.

Question 12

Struggle for existence

Answer 12

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

Question 13

Descent with modification

Answer 13

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

Question 14

Convergent evolution

Answer 14

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

Question 15

Divergent evolution

Answer 15

Two or more species becoming more and more dissimilar.

Question 16

Analogous structures

Answer 16

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

Question 17

Vestigial organs

Answer 17

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

Question 18

Homologous body structures

Answer 18

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

Question 19

Mutagens

Answer 19

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

Question 20

Mutations

Answer 20

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.

Question 21

How do variations occur

Answer 21

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.

Question 22

Single gene traits

Answer 22

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

Question 23

Directional selection

Answer 23

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

Question 24

Stabilizing selection

Answer 24

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

Question 25

Disruptive selection

Answer 25

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

Question 26

Speciation

Answer 26

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

Question 27

Species

Answer 27

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

Question 28

Process of speciation

Answer 28

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.

Question 29

Reproductive isolation

Answer 29

When two populations cannot interbreed and produce fertile offspring.

Question 30

Geographic isolation

Answer 30

When two populations are reproductively isolated by geographic formations.

Question 31

Behavioral isolation

Answer 31

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

Question 32

Temporal isolation

Answer 32

When two or more species reproduce at different times.

Question 33

Phenotype

Answer 33

Physical expression of genotype.

Question 34

Genotype

Answer 34

Genetic makeup of an organism.

Question 35

Recessive

Answer 35

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

Question 36

Dominant

Answer 36

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

Question 37

Homozygous

Answer 37

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

Question 38

Heterozygous

Answer 38

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