Evolution & Classification - Linn-Benton Community...

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1/9/2014 1 Evolution & Classification BI 101 General Biology Learning Goals 1. Define evolution and understand evolution by Natural Selection. 2. Understand how biologist classify organisms. 3. Recognize Linnaean Taxonomic hierarchy of classification. 4. Interpret phylogenetic trees (aka a phylogeny or evolutionary tree)

Transcript of Evolution & Classification - Linn-Benton Community...

1/9/2014

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Evolution & Classification

BI 101 General Biology

Learning Goals

1. Define evolution and understand

evolution by Natural Selection.

2. Understand how biologist classify

organisms.

3. Recognize Linnaean Taxonomic

hierarchy of classification.

4. Interpret phylogenetic trees (aka a

phylogeny or evolutionary tree)

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1. What is evolution?

2. Can religion and evolution

be compatible?

Discuss what you think evolution is with

your groups

~ 5 min

Evidence for evolution

Genetics: DNA

Paleontology: Fossils

Morphology: Homology

Biogeography :Geographic distribution

of organisms

Microevolution- observed changes

within populations of a species

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Evidence for evolution

Genetic

Genes coding proteins in our DNA is

Yeast - 45% identical

Fruit flies - 60% identical

Chickens - 90% identical

Rabbits - 95% identical

Chimpanzees - 98% identical!

Evidence for evolution:

Morphology Homology - A characteristic shared by

different organisms with common

ancestry

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Evidence for evolution

Morphology Vestigial organs– have no use

Example: appendix, wisdom teeth, human

tailbone, hind leg bones in whales,

Ostrich wings (they don’t fly)

Texas blind

salamander:

eyes that do

not see

Evidence for evolution

Biogeography Geographic distribution of organisms

Example: the finches of the Galapagos

Islands

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How can we organize

the diversity of life?

Taxon: A Ranked Hierarchy

Kingdom: Plantae

Phylum: Magnoliophyta

Class: Magnoliopsida

Order: Rosales

Family: Rosaceae

Genus: Malus

Species: Malus pumila

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Organizing Principle:

We can use relationships between

organisms to organize the diversity

of life

Descent with modification

Making Sense of it All

Traditional classification schemes

rank species into a hierarchy

Newer methods group species by

shared ancestry.

This reflects evolutionary history.

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Kingdoms and Domains

Bacteria Archaea Eukarya

Bacteria Archaea Protista Plantae Fungi Animalia

Monera Protista Plantae Fungi Animalia

The three-domain system

The six-kingdom system

The traditional five-kingdom system

Phylogeny Phylon = tribe (Greek)

Genesis = origin (Greek)

The evolutionary history of a species or group of species.

Goal is to show relationships and patterns of descent i.e. to make models called:

Phylogenetic Trees

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Hypothetical genealogy

of local population of

plants

Fig. 2. How genealogy of sexual

population is included in a phylogenetic

tree

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Tree diagram is meant to represent an

actual history of evolutionary lineages that

have branched over time

Reading the tree is like

traveling through family history

Speciation events occur at the

branch points, show when

ancestral lineage gives rise to

daughter lineage.

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Each living species has a unique lineage

as well as parts shared with others

Some important terms used

to describe phylogenetic trees

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A clade includes all

and only the

descendants of a

particular ancestor

A clade includes all and only

the descendants of a particular

ancestor

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Clades are nested within each

other:

How trees

show

evolutionary

history

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Trees, not ladders

Trees in each box all depict the same

evolutionary history!

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Four trees, all depict

same evolutionary history

• Now convince your partner– What do you

think?

• Why do you think your answer is right?

• Did you change your mind?

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• Now convince your partner– What do you

think?

• Why do you think your answer is right?

• Did you change your mind?

• Now convince your partner– What do you

think?

• Why do you think your answer is right?

• Did you change your mind?

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• Now convince your partner– What do you

think?

• Why do you think your answer is right?

• Did you change your mind?

What is misleading about this

picture?

It implies we evolved from apes we see

today!

It also implies individuals evolve, while

we know populations evolve

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One hypothesis

Most recent

common

ancestor

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Discuss Which organism would you venture to

guess is more closely related to the

Chinook salmon: a Great white shark or a

Beaver? Why?

Discuss

Ch 24 in textbook

See page 448, figure 24-1

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Ch 18 p. 348-349

Work on the exercise at the end of the

section

Then compare answers with your group

members

Additional Resources:

http://tolweb.org/tree/phylogeny.html

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Terms to know

1. Evolution

2. Natural Selection & Artificial selection

3. Phylogeny/phylogenetic tree

4. Clade

5. Derived adaptation

6. Node

7. Microevolution

8. Macroevolution

9. Coevolution

Friday

Natural Selection of Guppies Lab

Bring your laptop if you have one