lecture 6 flashcards

Anthropology 200 with Aubry at Ohio State University - All Campuses

About this deck

By: Sarah Ruth
Textbook:

Our Origins: Discovering Physical Anthropology
Created: 2010-04-28
Size: 38 flashcards
Views: 5

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Biological species concept

a species is one or more populations od organisms with the potential to interbreed with one another and produce fertile offspring

Macroevolution

Long term effects of evolutionary change through time
Often leads to speciation

Long term effects of evolutionary change through time

Can be looked at a long-term microevolutionary change

What is a species

Group of organisms that can interbreed and Produce fertile offspring
Biological species concept: a species is one or more populations od organisms with the potential to interbreed with one another and produce fertile offspring

Modes of evolution

Speciation- new species produced from earlier ones
One species evolving through time (anagenesis)

One species evolving through time

(anagenesis)

One species evolving into more than one species

(cladogenesis- birth of a new clade or new branch/ lineage)

What leads to new species

Disruptive or directional selection can lead to new species
Speciation occurs when differences between subpopulations become so large that interbreeding does not produce fertile offspring

Speciation

For speciation to occur populations of the same species must be reproductively isolated from each other( no gene flow)--- populations adapt to their local environments

Disruptive

or directional selection can lead to new species

Reproductive isolating mechanisms

Prezygotic barriers
Postzygotic barriers

Prezygotic barriers

Geographic isolation
Behavioral isolation
Temporal isolation
Mechanical isolation

Modes of speciation

Allopatric speciation

Postzygotic barriers

Reduced hybrid viability
Reduced hybrid fertility

Allopatric speciation

Geographically separeated populatios (no gene flow)

MAcroevolutionanry processes

Adaptive radiation- rapid expansion and diversification of organisms into new ecological niches
A species will diverge into many variations

Adaptive radiation- rapid expansion and diversification of organisms into new ecological niches

May produce an abundance of species over time

Macroevolutionary processes

Adaptive radiations often follow mass extinctions, or the colonization of new land.

A species will diverge into many variations

If the species had adaptive potential( the more general, the better) (generalized and specialized traits)
If there is adaptive opportunity in the available zones (ecological niches)

MACROEVOLUTION: ADAPTIVE RADIATION THROUGH COLONZATIONS

Can lead to the relatively rapid speciation events

Rate of evolutionary change

Fast or slow? Darwin believed it to be gradually slow evolution

Gradualism

Phyletic gradulism-change gradually in evolving lineage

If entre fossil record were pre look graded
Incompletness of fossil record rarity in finely graded transitic species

Punctuated equilibrium

Punctuated equilibrium- long periods of evolutionary stasis punctuated by ?Rapid? change
Long periods of stasis are punctuated by rapid periods of evolutionary change (e.g. adaptive radiation)

MAcroevolutionary processes

Defined by classification
Classification- orgering organisms into catergories

Classification- orgering organisms into catergories

Indicates evolutionary relationships

Must reflect evolutionary decent

Exp. Similar skeletal structures in tetrapods

Evolutionary systematics (i.e. cladistics)

Look at all homologies to determine evolutionary relationships and ancestor-decentent relationships. Construct a phylogenic tree

Analogies- structures shared by species as a result of common function (also homoplasy)

Convergent evolution- process that leads to the development of analogies, ancestry may be remote relatively recent

Phylogenetic tree- chart showing ecolutionary relationships

Includes the dimension of time
Determined by phylogenetic systematics

Classfication

Some homologies are more informative than others

Derived traits- characters modified from te ancestral condition defining a particular evolutionary lineage
Ancestral traits- characters shared through ancestry more remote than common ancestor

Classification: Cladistics

Cladistics- acknowledged that some homologies provide more useful information
Cladogram- chart showing evolutionary relationships

Cladogram- chart showing evolutionary relationships

Does not include the dimension of time
Based solely on shared derived characteristics
Does not clearly demonstrate ancestor-decendant- relationship

MACROEVOLUTION

ADAPTIVE RADIATION THROUGH COLONZATIONS

Fast or slow

Darwin believed it to be gradually slow evolution

Cladistics-

acknowledged that some homologies provide more useful information

Cladogram-

Does not include the dimension of time
Based solely on shared derived characteristics
Does not clearly demonstrate ancestor-decendant- relationship

About this deck

By: Sarah Ruth
Textbook:

Our Origins: Discovering Physical Anthropology
Created: 2010-04-28
Size: 38 flashcards
Views: 5

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy