Chapter 18

Front 1

Who first conceived the idea of evolution and described the mechanism by which it occurred?

Back 1

darwin and wallace

Front 2

Where was the last island Darwin visited?

Back 2

Galapagos Islands

Front 3

What did he notice about several of the animals there?

Back 3

they were similar but had different, special adaptations

Front 4

What did he notice about the ground finches that supported the idea of a common ancestor and evolution?

Back 4

He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources.

Front 5

How did beak size affect the survival of the ground finches?

Back 5

the type of food determined which beak would survive best

Front 6

How does natural selection occur?

Back 6

Survival of the fittest

Front 7

Why did Darwin propose giant tortoises survived better than the normal tortoises on the Galapagos islands?

Back 7

These tortoises were “selected” because they could reach more leaves and access more food than those with short necks. they had no competition

Front 8

Natural selection can occur if there is __________ among a trait.

Back 8

variation (must be inherited)

Front 9

What are the two main mechanisms of genetic diversity?

Back 9

Mutation and sexual reproduction

Front 10

What is it called if an inherited trait helps an organism survive?

Back 10

adaptation

Front 11

Are certain traits all considered to be positive? Why or why not?

Back 11

no. Whether or not a trait is favorable depends on the environmental conditions at the time. The same traits are not always selected because environmental conditions can change

Front 12

What is divergent evolution?

Back 12

When two species evolve in diverse directions from a common point

Front 13

What is convergent evolution?

Back 13

When similar phenotypes evolve independently in distantly related species (become one species)

Front 14

What are five of the pieces of evidence for evolution (subheadings)?

Back 14

Fossils, anatomy and embryology, biogeography, molecular biology

Front 15

what are homologous structures?

Back 15

structures that look the same. appendages

Front 16

What are vestigial structures? what are some examples?

Back 16

unused structures without function. pelvis/femur in a whale

Front 17

How is embryology used to study evolution?

Back 17

provides evidence of relatedness between now widely divergent groups of organisms

Front 18

What is biogeography explain? How does it explain evolution?

Back 18

The geographic distribution of organisms on the planet follow patterns that are best explained by evolution in conjunction with the movement of tectonic plates over geological time.

Front 19

What are the four misconceptions mentioned about evolution?

Back 19

Evolution is just a theory, individuals evolve, evolution explains the origin of life, organisms evolve on purpose,

Front 20

Does the theory of evolution support the idea that individuals evolve? If not how does it describe evolution occurs?

Back 20

No. Evolution is the change in genetic composition of a population over time, specifically over generations, resulting from differential reproduction of individuals with certain alleles

Front 21

Do organisms evolve intentionally? If not how does it occur?

Back 21

A changed environment results in some individuals in the population, those with particular phenotypes, benefiting and therefore producing proportionately more offspring than other phenotypes. This results in change in the population if the characteristics are genetically determined.

Front 22

What is a species?

Back 22

a group of individual organisms that interbreed and produce fertile, viable offspring

Front 23

How is a hybrid formed and can they reproduce?

Back 23

two species mate and make another species, no

Front 24

Changes must occur to what cells to be passed onto offspring?

Back 24

Reproducing cell, gametes

Front 25

What is speciation?

Back 25

the formation of two species from one original species

Front 26

What must occur in order for speciation to have occurred?

Back 26

Two new populations must be formed from one original population and they must evolve in such a way that it becomes impossible for individuals from the two new populations to interbreed

Front 27

What is the difference between Allopatric and Sympatric speciation?

Back 27

Allopatric- involves geographic separation of populations from a parent species and subsequent evolution

Sympatric- involves speciation occurring within a parent species remaining in one location

Front 28

What about geographic separation causes speciation to occur?

Back 28

These species can then evolve among different trajectories

Front 29

Dispersive

Back 29

refers to species moving to new geographic regions

Front 30

Vicariance-

Back 30

refers to when a natural situation arises to physically divide two populations

Front 31

Why is it that the greater the distance, the greater the chance of speciation?

Back 31

As the distance increases, the various environmental factors would likely have less in common locations in close proximity.

Front 32

What are the two type of reproductive barriers?

Back 32

Prezygotic barrier, Postzygotic barrier

Front 33

Prezygotic barrier

Back 33

a mechanism that blocks reproduction from taking place.

Front 34

temporal isolation

Back 34

two species mate at different times so they can never create another species

Front 35

habitat isolation

Back 35

when breeding location does not overlap

Front 36

behavioral isolation

Back 36

behavior makes it to where species do not want to mate

Front 37

gametic barriers

Back 37

reproductive organs dont fit together

Front 38

Postzygotic

Back 38

organisms that are born sterile or don’t survive the embryonic stage

Front 39

What is a hybrid zone ?

Back 39

An area where two closely related continue to interact and reproduce forming hybrids.

Front 40

three ways can it be changed over time

Back 40

reinforcement- makes species diverge even more

fusion- two species reproduce and eventually become one species

stability- if they stayed exactly the same

Front 41

What are the two rates of speciation?

Back 41

Gradual speciation and punctuated equilibrium

Front 42

What is the gradual speciation model?

Back 42

Species diverge gradually over time in small steps

Front 43

What is the punctuated equilibrium model?

Back 43

A new species undergoes changes quickly from the parent species, and then remains largely unchanged for long periods of time afterward