Module #12: Speciation

Question 1

Microevolution

Answer 1

evolutionary change at the (sub)population level

Question 2

Macroevolution

Answer 2

evolutionary change resulting in speciation or divergence at even higher levels

Question 3

Mutation

Answer 3

heritable change in DNA that alters the genetic information carried in a cell, potentially leading to an alteration of a phenotype

Question 4

Hybridization

Answer 4

interbreeding of two divergent populations/species that creates a third population/species with a distinct genotype and phenotype (often a polyploid)

Question 5

Natural Selection

Answer 5

process by which individuals differentially leave more/less descendants than others because they possess certain inherited advantages/disadvantages

Question 6

Directional selection

Answer 6

unidirectional change, adaptation to a new environment or environmental change

Question 7

Stabilizing selection

Answer 7

Adaptation to a stable environment, favoring average individuals

Question 8

Disruptive selection

Answer 8

favors both extremes, such as in a population which straddles two different ecological zones

Question 9

Cladistics

Answer 9

biological classification that attempts to find phylogenetic relationships by constructing branching diagrams based on shared derived characteristics.

Question 10

Phylogeny

Answer 10

the relationships between a set of organisms as seen in the genealogical links between ancestors and descenants

Question 11

Speciation

Answer 11

branching of lineages; any process of species formation

Question 12

extinction

Answer 12

the termination of a lineage, the eventual outcome of all species

Question 13

Clade

Answer 13

a cluster of lineages produced by repeated branching from a common ancestor

Question 14

Phylogeography

Answer 14

Field that analyzes the geographical distribution of genealogical lineages, and links past events and processes associated with those geographical locations with genetic divergence and speciation

Question 15

Large continuous variation (a type of geographical variation)

Answer 15

ex: trees and plains grasses

Have polymorphic local populations within them with characteristic balances of polymorphic types fashioned by gene flow and various selection types

Question 16

Disjunct variation (type of geographical variation)

Answer 16

evolve where a population is discontinuous, comprising a set of island-like, spatially separate subpopulations

Question 17

phylogenetic species concept

Answer 17

species are based on divergences in genealogical/evolutionary lineages

Question 18

Gradualism

Answer 18

SPECIATION may be a slow, gradual process, as Darwin proposed under natural selection

Question 19

Punctuated Equilibrium

Answer 19

Speciation may occur rapidly, catastrophically, in a series of major jumps, perhaps caused by some change in background radiation or rapid climatic changes, polyploidy, hybridization, etc.

Question 20

Allopatric speciation

Answer 20

Geographically separated populations are genetically isolated; i.e. no gene flow among pops and they evolve separately

aka geographical speciation

Question 21

Vicariance

Answer 21

Splitting apart of a species distribution by geological or environmental affect.. resulting in a pair of closely related species

Question 22

Parapatric speciation

Answer 22

When a species is spread out over a large geographic area, but only reproduces with local species, resulting in the development of a new species

Question 23

Sympatric Speciation

Answer 23

a new species forms that totally overlaps with the range of the parent species

-could arise due to disruptive selection, or changes in chromosome number (polyploidy)

Question 24

Adaptive radiation

Answer 24

the classification of species to fill a wide variety of ecological niches

or, the rise of a diversity of ecological roles and attendant adaptations in different species within a lineage

-they diverge to avoid interspecific competition, perhaps after a recent colonization event (ex: darwin’s finches)