Ch.29: Evolutionary Genetics

Question 1

What is a species?

Answer 1

a group of individuals whose members can interbreed to produce viable, fertile offspring; members of one species cannot successfully interbreed with members of other species

Question 2

What are the 2 ways to achieve reproductive isolation?

Answer 2

-Prezygotic isolating mechanisms that prevent the formation of a zygote (ex. habitat, temporal, mechanical, or gametic isolation)

-Postzygotic isolating mechanisms prevent the development
of a viable individual after fertilization has taken place (ex. hybrid inviability, sterility, or breakdown)

Question 3

What is the biological species concept?

Answer 3

a species is a group of individuals whose members have the
potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species

Question 4

What is the evolutionary species concept?

Answer 4

A species should be defined based on the separate evolution of lineages

Question 5

What is the ecological species concept?

Answer 5

Each species occupies an ecological niche, which is a unique set of habitat resources the species requires

Question 6

What is the general lineage concept?

Answer 6

-Each species is a population of an independently evolving lineage and has evolved from a specific series of ancestors, so each forms a group of organisms with a particular set of
characteristics.
-Multiple criteria are used to determine if a given population is part of an independent evolutionary lineage; morphology, reproductive isolation,
DNA sequence and ecology
-Most researchers agree that the general lineage concept is the best way to define species

Question 7

What is Anagenesis?

Answer 7

A single species is transformed into a different species over
the course of many generations

Question 8

What is Cladogenesis?

Answer 8

A single species is divided into two or more species; This is the most common form of speciation

Question 9

What is allopatric?

Answer 9

Two large populations are separated by geographic barriers
or a small population separates from the main population and
becomes geographically separated

Question 10

What is Parapatric?

Answer 10

Two populations are partially separated geographically

Question 11

What is Sympatric?

Answer 11

A small group evolves into a reproductively separate species
Does not involve geographic separation

Question 12

What is phylogeny? What is a phylogenetic tree?

Answer 12

-the sequence of events involved in the evolutionary development of a species or group of species

-A phylogenetic tree is a diagram that describes the phylogeny
of a species

Question 13

What are the 2 different approaches to construct a phylogenetic tree?

Answer 13

-Phenetic approach: Trees are constructed by comparing overall similarities without trying to understand evolutionary history
-Cladistic approach: Trees are constructed by choosing the best amongst various paths of evolution

Question 14

What is an ingroup?

Answer 14

a species or group of species that is monophyletic or derived
from a common ancestor – an ingroup is related

Question 15

What is an outgroup?

Answer 15

a species or group of species that are ancestral or more
distantly related – an outgroup is not related

Question 16

What is the Principle of parsimony?

Answer 16

the preferred hypothesis is the one that is the simplest

Question 17

What 2 genes are said to be homologous if they are derived from the same ancestral gene?

Answer 17

-Orthologous genes/orthologs: homologous genes found in different species
-Paralogous genes/paralogs: homologous genes found within a single species

Question 18

What do fossil records show the mammalian timeline of earth as?

Answer 18

Monkeys -> Gorillas -> Humans

Question 19

What is the most genetic variation observed in natural populations due to?

Answer 19

the accumulation of neutral mutations

Question 20

What has the Kimura “neutral theory of evolution” has been called?

Answer 20

“survival of the luckiest theory” and also non-Darwinian evolution in order to contrast it with Darwin’s “survival of the fittest theory” ; believed most modern variation in
gene sequences is explained by neutral variation

Question 21

How does the advent of molecular techniques help with the analysis of
chromosomes from different species?

Answer 21

-can help researchers identify regions that contain the same groups of linked genes, or synteny groups
-Within a particular synteny group, the same types of genes are found in the same order