Chapter 24 The origin of species

Question 1

SPECIATION

Answer 1

The process by which one species splits into 2 or more species

Question 2

MICROEVOLUTION

Answer 2

Changes of allele frequency in a population

Question 3

MACROEVOLUTION

Answer 3

The broad pattern of evolution above the species level.

Eg. Is the origin of new groups of organisms through a series of speciation events

Question 4

4 for mechanisms of Microevolution

Answer 4

.Mutation
.Natural Selection
. Genetic Drift
.Gene Flow

Question 5

Why was Darwin fascinated with Speciation

Answer 5

. Because it is responsible for the diversity of life
.It explains the difference between species
. “ “ “ “””””””” the similarities ( as from a common ancestor the unity of life)

Question 6

SPECIES

Answer 6

THE BIOLOGICAL SPECIES CONCEPT: It is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring- but not produce viable, fertile offspring with members of other such groups.

. thus the members of biological species are united ( are define in terms of )by being reproductively compatible

Scientists have proposed more than two dozen ways to define species. One commonly used definition, called the biological species concept, holds that populations belong to the same species if they can contribute genes to a common gene pool. Reproductive barriers block gene flow between different species. Gene flow between populations tends to hold the gene pool of a species together.

Question 7

GENE FLOW

Answer 7

The transfer of alleles between populations.

it typically occurs between the different populations of a species

Question 8

POPULATIONS

Answer 8

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

Question 9

REPRODUCTIVE ISOLATION

Answer 9

Because biological species are defined in terms of reproductive compatibility, The formation of new species hinges on reproduction isolation.

. it is The existence of biological factors ( barriers) that impede members of two species from interbreeding and producing viable ( able to live after birth), fertile offspring.

… Such barriers block geneflow between species and limit the formation of hybrids

Genetic isolation

Question 10

HYBRIDS

Answer 10

Offsprings that result from an interspecific mating

Question 11

How are barriers classified

Answer 11

according to whether they contribute to reproductive isolation before or after fertilization
.PREZYGOTIC BARRIERS
.POSTZYGOTIC BARRIERS

Question 12

.PREZYGOTIC BARRIERS

Answer 12

. Block fertilization from occurring

Question 13

3 ways .PREZYGOTIC BARRIERS Block fertilization from occurring

Answer 13

1. by impeding members of different species from attempting to mate

. To prevent an attempting mating from being completely successful

. hindering fertilization if mating is successful

Question 14

5 types of .PREZYGOTIC BARRIERS

Answer 14

1. Habitat Isolation ( 2 species that occury differet habitats may encounter each other rarely
2. Temporal isolation

Question 15

How does speciation occur

Answer 15

By the evolution of reproductive isolation

Question 16

Morphological species Concept

Answer 16

Characterizes a species by shape and other structural features

Question 17

ECOLOGICAL SPECIES CONCEPT

Answer 17

views a species in terms of its ecological niche, the sum of how members of the species interact with non living and living parts of their environment. Emphasizes disruptive selection, as organisms adapt to their environment

Question 18

PHYLOGENIC SPECIES CONCEPT

Answer 18

Defines a species as the smallest group of individuals that share a common ancestor forming one branch on the tree of life. This is done by comparing characteristics such as morphology molecular sequences with those of other organisms

Question 19

The five types of pre-zygotic barriers are

Answer 19

habitat isolation
Temporal isolation
Behavioral isolation
Mechanical isolation
Gametic isolation

Question 20

Habitat isolation

Answer 20

Two species that occupy different habitats within the same area may encounter each other rarely if at all even though they’re not isolated by obvious physical barriers such as Mountain ranges

Question 21

Temporal isolation

Answer 21

Species that breed during different times of the day different seasons or different years cannot mix their gametes

Question 22

Behavioral isolation

Answer 22

Courtship rituals enable mate recognition - a way to identify potential mates of the same species. Different behavioral rituals will act as a reproduction barrier

Question 23

Mechanical isolation

Answer 23

Mating is attempted but morphological differences prevent its successful completion

Question 24

Gametic isolation

Answer 24

Sperm of one species may not be able to fertilize the eggs of another species

Question 25

Three types off post zygotic barriers.

Answer 25

Reduced hybrid viability
Reduced hybrid fertility
Hybrid breakdown

Question 26

The genes of different parent species may interact in ways that impair the hybrids development of survival in its environment

Answer 26

Reduced hybrid viability

Question 27

Reduced hybrid fertility

Answer 27

Even if hybrids are vigorous they may be sterile.

Question 28

Hybrid breakdown

Answer 28

Envelope if first generation hybrids are fertile and vigorous. their offspring of next generation may be feeble or sterile.

Question 29

2 ways that speciation can occur

Answer 29

. Allopatric speciation

.Sympatric speciation

Question 30

ALLOPATRIC SPECIATION

Answer 30

(Other country)
Gene flow is interrupted when a population is divided into geographically isolated subpopulation. It can occur without geographical remodeling. Eg. When individuals colonize a remote area and their descendants become geographically isolated from the parent population.

Question 31

SYMPATRIC SPECIATION

Answer 31

Occurs in populations that live in the same geographic area

Question 32

3 means of Sympatric speciation where gene flow is reduced

Answer 32

.polyploidy
.habitat differentiation
.sexual selection

Question 33

Polyploidy

Answer 33

A species may originate from accident during cell division that results in extra sets of chromosomes . More common in plants

Question 34

2 distinct forms of polyploidy

Answer 34

Auto polyploid

Allopolyploid

Question 35

Auto polyploid

Answer 35

An individual that has more than 2 chromosome sets that are derived from a single species. 2n to 4 n