Evolution

Front 1

What did Darwin mean by "descent with modification".

Back 1

Animals change from ancestors to something more different but are still the same.

Front 2

Evolution

Back 2

Change of frequency of alleles in a population

Front 3

Lamarck theory

Back 3

Traits could be acquired during lifetime depending how often it is used. Traits that were used would be passed on.

Front 4

What is natural variation?

Back 4

Differences among individuals of a species. -Can be found in all species

Front 5

What is artificial selection?

Back 5

Nature provieded variation among different organisms, and humans selected the variations that were found useful.

Front 6

What is fitness?

Back 6

An individual's ability to survive and reproduce in its environment.

Front 7

Adaptation

Back 7

Any inherited characteristic that increases an organism's chance of survival.

Front 8

Survival of the fittest

Back 8

Individuals w/ low fitness die or leave few offspring. Individuals with high fitness- survive and reproduce.

Front 9

Natural selection

Back 9

Traits being selected by nature that contribute to an organism's fitness in its environment.

Front 10

What happens over time in natural selection?

Back 10

Natural selection results in changes in the inherited characteristics of a pop. The changes increase a species' fitness in environment.

Front 11

Descent with modification

Back 11

Each living species descended, with changes, from other species over time.

Front 12

Common descent

Back 12

All species-living and extinct- came from common ancestors.

Front 13

"Tree of life"

Back 13

Links all living things on Earth

Front 14

Evidence for the process of evolution can be found in where?

Back 14

Fossil record, where living organisms are placed geographically, homologous structures of living organisms, and similarities in early development.

Front 15

How can two species that look different from each other be more closely related than two other secies that look similar to each other?

Back 15

Species living on different continents had different ancestors. But they lived under similar ecological conditions and faced with similar pressures of natural selection, different species ended up evolving some features in common.

Front 16

Homologous Structures

Back 16

Differ greatly in form and function, but made from the same basic bones.
-different form and function, but made from same basic bones.

Front 17

Vestigial organs

Back 17

Like the human appendix. Structures hardly used and reduced in size.

Front 18

Descent with modification

Back 18

Each living species descended, with changes, from other species over time.

Front 19

Common descent

Back 19

All species-living and extinct- came from common ancestors.

Front 20

"Tree of life"

Back 20

Links all living things on Earth

Front 21

Evidence for the process of evolution can be found in where?

Back 21

Fossil record, where living organisms are placed geographically, homologous structures of living organisms, and similarities in early development.

Front 22

How can two species that look different from each other be more closely related than two other secies that look similar to each other?

Back 22

Species living on different continents had different ancestors. But they lived under similar ecological conditions and faced with similar pressures of natural selection, different species ended up evolving some features in common.

Front 23

What are the two main sources of genetic variation?

Back 23

-Mutations
-Genetic shuffling (from sex. reproduction)

Front 24

What does the number of phenotypes of made for a given trait depend on?

Back 24

It depends on how many genes control the trait.

Front 25

Single-gene trait

Back 25

Trait tat is controlled by a single gene that has two alleles. (widows peak)

Front 26

Polygenic traits

Back 26

Traits that are controlled by two or more genes. (height)

Front 27

Natural selection on single-gene traits can lead to what?

Back 27

Leads to changes in allele frequencies, then to evolution.

Front 28

Natural selection can affect the distributions of phenotypes in three ways.

Back 28

Directional, stabilizing, disruptive selection

Front 29

What is genetic drift?

Back 29

Random change in allele frequency

Front 30

What is genetic equilibrium?

Back 30

Situation where allele frequencies remain constant

Front 31

What 5 conditions are needed to maintain genetic equilibrium?

Back 31

-Random mating
-population must be large
-no movement into or out of population
-no mutation
-no natural selection

Front 32

Reproductive isolation

Back 32

When members of two populations cannot interbreed and produce offspring

Front 33

behavioral isolation

Back 33

Is one of three reproductive isolations. Two populations are able to interbreed but choose not to because of differences in mating rituals.

Front 34

Geographic Isolation

Back 34

Two populations are unable to interbreed due to a natural barrier. Rivers, mountains, bodies of water

Front 35

Temporal Isolation

Back 35

Two populations reproduce at different times. E.g; 3 similar species of orchid releases pollen only on a single day. They release pollen on different days, so they cannot pollinate one another.

Front 36

How is reproductive isolation related to the formation of new species?

Back 36

When gene pools get to be very different because of reproductive isolation eventually two populations will not interbreed with each other. The two gene pools remain isolated from each other- even when living together in the same place. The two populations are now two species.

Front 37

Allele frequencies can change by

Back 37

Natural Selection and Genetic Drift

Front 38

Natural selection acts on

Back 38

Single-gene traits and polygenic traits

Front 39

Polygenic traits can be affected by

Back 39

Directional selection, Stabilizing direction, and disruptive selection