Formation of New Species

Question 1

Species

Answer 1

A group of organisms that can interbreed and produce viable, fertile offspring

Question 2

Hybrid

Answer 2

A cross between two species

Question 3

Gene pool

Answer 3

A collection of all the variants of genes in a species

Question 4

Speciation

Answer 4

A formation of two species from one original species

Question 5

When can speciation occur?

Answer 5

1) When groups become isolated geographically for a long period of time
2) Changes (mutations) in each group over time lead to the groups no longer being reproductively compatible

Question 6

Biological Species Concept:
Members of the same biological species…

Answer 6

-Share the same gene pool (there is gene flow between two populations)
-Are reproductively isolated from other species (by natural biological barriers)

Question 7

The Only Illustration in Darwin’s On the Origin of Species

Answer 7

A diagram showing speciation events leading to biological diversity. The diagram shows similarities to phylogenetic charts that are drawn today to illustrate the relationships of species.
Modern elephants evolved from the Palaeomastodon, a species that lived in Egypt 35–50 million years ago

Question 8

Allopatric Speciation

Answer 8

Involves geographic isolation
-Dispersal
-Vicariance
-Adaptive radiation
Ex) Northern spotted owl and Mexican spotted owl look similar to one another but inhabit geographically separate locations

Question 9

Sympatric Speciation

Answer 9

Occurs in the same geographical area; Speciation with the same physical location and conditions
-Chromosomal errors in cell division
-Reproductive isolation

Question 10

Allopatric Speciation: Dispersal

Answer 10

When a few members of a species purposefully migrate/move to a new geographical area

Question 11

Allopatric Speciation: Vicariance

Answer 11

When a natural situation/disaster arises to physically divide organisms; Sometimes gene flow reoccurs in an area when something that was isolating two groups is removed

Question 12

Allopatric Speciation: Adaptive Radiation

Answer 12

From one original species, multiple others evolved, each with their own characteristics
Ex) Darwin’s finches and Honeycreeper birds

Question 13

Sympatric Speciation: Errors in Chromosome Segregation

Answer 13

Aneuploidy - abnormality in number of chromosomes in the cell
Autopolyploidy - more than 2 sets of chromosomes from the same species; when mitosis isn’t followed by cytokinesis
Allopolyploidy - more than 2 sets of chromosomes from different species; gametes from 2 different species combine

Question 14

Sympatric Speciation: Prezygotic Barriers

Answer 14

Prevent members of different species from mating to produce a zygote
-Temporal Isolation
-Habitat Isolation
-Behavioral Isolation
-Gametic Barriers

Question 15

Sympatric Speciation: Temporal Isolation

Answer 15

A form of prezygotic barrier; when 2 or more species have different breeding schedules
Ex) Cicadas

Question 16

Sympatric Speciation: Habitat Isolation

Answer 16

A form of prezygotic barrier; when members of species move; mismatches in habitat preferences

Question 17

Sympatric Speciation: Behavioral Isolation

Answer 17

A form of prezygotic barrier;
Certain actions or lack of them impacts reproduction

Question 18

Sympatric Speciation: Gametic Barriers

Answer 18

A form of prezygotic barrier;
incompatibility of reproductive species or games prevent fertilization; the shape of the male reproductive organ varies among male species
-Only compatible with the female of that species
-Reproductive organ incompatibility keeps the species reproductively isolated

Question 19

Sympatric Speciation: Postzygotic Barriers

Answer 19

Keeps hybrid zygotes (one-celled embryos with parents of two different species) from developing into healthy, fertile adults; Prevents successful reproduction and leads to speciation
-Hybrid Inviability
-Hybrid Sterility

Question 20

Sympatric Speciation: Hybrid Inviability

Answer 20

A form of postzygotic barrier; embryo produced but cannot survive development
Ex) Liger

Question 21

Sympatric Speciation: Hybrid Sterility

Answer 21

A form of postzygotic barrier; different species produce viable offspring but offspring cannot reproduce
Ex) Mule

Question 22

Other ways to define species

Answer 22

-Morphological species
-Ecological species
-Phylogenetic species

Question 23

Morphological Species

Answer 23

A group of organisms that are morphologically (anatomically) similar; Individuals in different species are different in morphology

Question 24

Ecological Species

Answer 24

Set of organisms adapted to specific resources

Question 25

Phylogenetic Species

Answer 25

Set of organisms that share a common ancestor