Natural Selection

Front 1

What is evolution?

Back 1

Decent with modification

Front 2

Can an individual evolve?

Back 2

-No- only a population can evolve

Front 3

What discovery revolutionized TB treatment?

Back 3

-antibiotics

Front 4

Why have the numbers of TB cases worldwide been increasing since the 1980's?

Back 4

-TB is becoming resistant to antibiotics

Front 5

What is natural selection?

Back 5

-When the environment is impacting which organisms survive to reproduce

Front 6

What was the first publication discussing the idea of natural selection?

Back 6

-"The Origin of Species" by Charles Darwin

Front 7

What ideas does evolution include?

Back 7

-Species accumulate differences
-Descendants differ from their ancestors
-New species arise from existing ones

Front 8

What are adaptations?

Back 8

-species originate from a common ancestor, but are able to change in response to their environment

Front 9

What is artificial selection?

Back 9

-modification of a species by selecting and breeding individuals with desired traits

Front 10

What are Darwin's "four observations of nature?"

Back 10

-1-Individuals within populations vary
-2-Some of the variation can be passed to offspring
-3-Populations produce more offspring than will survive
-4-Survival and reproduction are not random

Front 11

What are the two inferences that Darwin gathered from his four observations of nature?

Back 11

-1-Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals
-2-This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

Front 12

What does "best fit" mean?

Back 12

-it is a description of what organism works (and is able to reproduce) the best within the environment

Front 13

In what ways is natural selection an observable phenomena?

Back 13

-convergent evolution
-mimicry

Front 14

What is convergent evolution?

Back 14

-similar traits show up in different organisms as a response to the same natural pressures

Front 15

In what types of environments is convergent evolution often seen?

Back 15

-environments with continual pressure (examples: temperature-like desert-makes leaves a disadvantage...water-swimming shape to be hydrodynamic in water)

Front 16

What is mimicry?

Back 16

-when something evolves to look like something else

Front 17

What are three modes of selection?

Back 17

-directional selection
-disruptive selection
-stabilizing selection

Front 18

What does directional selection favor?

Back 18

-favors individuals at one end of the phenotypic range

Front 19

What does disruptive selection favor?

Back 19

-favors individuals at both extremes of the phenotypic range

Front 20

What does stabilizing selection favor?

Back 20

-favors immediate variants and acts against extreme phenotypes

Front 21

Why can't natural selection fashion perfect organisms?

Back 21

-selection can act only on existing variations
-adaptations are often compromises
-chance, natural selection, and the environment interact

Front 22

What are some example of other evidence of morphological changes over time?

Back 22

-embryology
-homologous structures
-vestigial structures

Front 23

_____ _____ suggests a common ancestor

Back 23

-Embryological similarity

Front 24

What are homologous structures?

Back 24

-structures with different appearances and functions that all derived from the same body part in a common ancestor

Front 25

_____ _____ have no apparent function, but resemble structures their ancestors possessed.

Back 25

-Vestigial structures

Front 26

SUMMARY CARD:
____ is an example of an organism that has evolved with pressure from antibiotics.
-Darwin's observations on his trip provided him with the idea of _____ _____.

Back 26

-Tuberculosis
-Natural selection

Front 27

SUMMARY CARD:
-Evolution is:
-Natural selection is:
-Evolution and natural selection are _____ _____.

Back 27

-descent with modification
-when the environment impacts an organism's ability to survive and reproduce
-observable phenomena

Front 28

What events (beyond natural selection) are considered evolutionary due to their impact on a population's gene pool?

Back 28

-mutation, migration, non-random mating and genetic drift

Front 29

What is the ultimate source of genetic variation?

Back 29

-Mutation

Front 30

How does non-random mating select for traits?

Back 30

-based on mating preferences (these traits will be passed on to the next generation)

Front 31

Migration consists of the movement of _____ between populations.

Back 31

-alleles

Front 32

In migration, how can alleles be transferred?

Back 32

-through the movement of individuals or gametes

Front 33

Migrations tends to reduce _____ between populations.

Back 33

-differences

Front 34

Which is more likely to alter allele frequencies directly, migration or mutation?

Back 34

-migration

Front 35

What is genetic drift?

Back 35

-random fluctuation in allele frequencies over time by chance

Front 36

What is the founder effect and in what type of evolution does it occur?

Back 36

-few individuals found new population. Occurs in genetic drift.

Front 37

What is the bottleneck effect and in what type of evolution does it occur?

Back 37

-drastic reduction in population and in gene pool size. Occurs in genetic drift.