Biology 100 Unit 14

Question 1

is the study of major biological changes seen in the fossil record (i.e., obvious structural differences).

Answer 1

macroevolution

Question 2

When changes accumulate to produce a completely distinct group of organisms, we call this ___________.

Answer 2

speciation

-This includes the origin of a new species (speciation).

Question 3

According to the ______________________, a species is a group of members in a population with the potential to interbreed and produce fertile offspring.

Answer 3

Biological Species concept

Question 4

According to the biological species concept a species is a

Answer 4

group of members in a population with the potential to interbreed and produce fertile offspring.

Question 5

Members of different species don’t mate due to

Answer 5

reproductive isolation.

Question 6

The biological species concept can be problematic. – Some pairs of clearly distinct species occasionally
interbreed and produce _____________.

Answer 6

hybrids

Question 7

– For example, grizzly bears and polar bears may interbreed and produce hybrids called ____________.

Answer 7

groolarbears

Question 8

_________________may bring these two bear species together more frequently and produce more hybrids in the wild.

– These 2 distinct species would not be reproductively isolated from each other, therefore difficult to classify as _______________________
– Alternate species concepts can be useful.

Answer 8

Melting sea ice

distinct species.

Question 9

Another species definition is the __________________ ____________, which identifies species in terms of their ecological niche, looking at their role in an community.

Answer 9

ecological species definition

Question 10

The ecological species concept

Answer 10

focuses on unique adaptations to particular roles in a

biological community.

Question 11

or example, two species may be similar in appearance but distinguishable based on

Answer 11

• what they eat

- where they live

Question 12

Lastly, the ___________________defines a species as the smallest group of individuals that share a common ancestor, forming a branch on an evolutionary tree.

Answer 12

phylogenetic species concept

Question 13

Biologists trace the phylogenetic history of a species by comparing its

Answer 13

DNA sequences

Question 14

Alternate ways of defining species using physical traits, shape, size or other features.

Answer 14

Morphological species concept

Question 15

Give two examples of the morphological species concept

Answer 15

• asexual organisms

- fossils

Question 16

prevent interbreeding and establish different species.

Answer 16

reproductive barriers

Question 17

What do reproductive barriers do

Answer 17

the isolate gene pool

Question 18

barriers prevent mating between different species.

Answer 18

prezgotic or postzygotic

Question 19

Generally fertile offspring are the result

Answer 19

of the same species mating, with few exceptions.

Question 20

Courtship ritual in blue-footed boobies is an example of one kind of prezygotic barrier, ________________.

Answer 20

behavioral isolation

Question 21

Structural differences don’t allow the genitals of these snails to mate

Answer 21

mechanical isolation

Question 22

mating or fertilizing occurs at different seasons

Answer 22

temporary isolation

Question 23

populations live in different habitats and therefore do not interact

Answer 23

habitat isolation

Question 24

Female and Male gametes fail to unite in fertilization

Answer 24

gametic isolation

Question 25

Should prezygotic barriers fail and interspecific fertilization occur forming a hybrid zygote, postzygotic barriers are additional mechanisms which

Answer 25

prevent future hybrids from developing

Question 26

Post zygotic barriers: most hybrid offspring do not survive.

Answer 26

reduced hybrid viability

Question 27

hybrid offspring are vigorous but sterile.

Answer 27

Reduced hybrid fertility

Question 28

the first-generation hybrids are viable and fertile but the offspring of the hybrids are usually sterile.

Answer 28

hybrid breakdown

Question 29

There are two main modes of speciation:

Answer 29

• allopatric speciation

- sympatric speciation

Question 30

Geographic isolation may cause a population to become genetically unique as its gene pool is changed by natural selection, genetic drift, or mutation.

Answer 30

allopatric speciation

Question 31

Sympatric speciation occurs if a _________________ _______________________ between parents and offspring

Answer 31

mutations may result in plant with a different number of chromosomes

Question 32

This is _________________: a multiple number of chromosomes,

Answer 32

poly ploidy

Question 33

If a parent cell fails to divide after DNA replication occurs, chromosomes duplicate, then ______________________ ______________________________________________.

Answer 33

self fertilize may result in plant with a different number of chromosomes

Question 34

This plant may be incompatible with others (due to the newly increased chromosome number) and considered a

Answer 34

distinct species.

Question 35

A farmer sows grain kernels from mixed plants in the wild.

 Some of the plants in the field hybridize and self-fertilize.

Answer 35

As a result, many domesticated plants are the result of sympatric speciation

Question 36

The evolution of many diverse species from a common ancestor is ______________________.

Answer 36

adaptive radiation

Question 37

An example of adaptive radiation can be found on the Galápagos islands

Answer 37

with the 14 different finch varieties considered to have arisen from a common ancestor from the mainland.

Question 38

n speciation,

Answer 38

a gradual accumulation of many changes, may account for a new species.

Question 39

speciation is called ________________, explaining how a new species evolved through the gradual accumulation of changes brought about by natural selection.

Answer 39

gradualism

Question 40

However, __________________________are found in the fossil record.

Answer 40

few transition fossils are found

Question 41

The _______________________ model is a contrasting model of macroevolution.

Answer 41

punctuated equalibrium

Question 42

This model proposes that species diverge in _______ ____________________ as a population diverges from the ancestral populations, with little or no change occurring for the remainder of the species’ existence.

Answer 42

spurts of relatively rapid change

Question 43

This would account for the relative _______________ ___________________________.

Answer 43

rarity of transitional fossils

Question 44

___________________: long periods of little change, or equilibrium punctuated by abrupt episodes of speciation

Answer 44

punctual equalibrium model

Question 45

__________________: Slow gradual changes over time

Answer 45

gradualist model

Question 46

But, how long exactly is a “punctuation”?

Answer 46

A punctuation may involve hundreds of generations.

Question 47

_______________________________changes may have occurred during the existence of a species.

Answer 47

both gradual and punctual

Question 48

This means that, in evolutionary time, even a ____________________change may take longer than humans can directly observe.

Answer 48

“punctuated”