• Similar traits often indicates common ancestry

• Phylogeny: evolutionary histories of a species

• Determined by examining:– Fossils

– Living specimens

– Molecular data

– Development

Fossil Evidence

• Homologous structures: body parts that have a similar structure, but different function

• Relationships identified among different species• Fossils link past life to modern life

Anatomy shows nonrelationships also

• Comparing DNA, amino acids, chromosomes, proteins

– Similarities and differences can be found

• DNA mutates at known rates

– Splits in evolution can be estimated

Chromosome order: Human, orangutan, gorilla, pygmy chimp

• Zygote divides by mitosis

(1 2 4 8)

• Blastula (ball of cells) forms

• Blastopore (small indentation) begins to form digestive system

• Blastopore develops into the anus of some animals and mouth of others

• Conclusion: Similar development indicates relationship

Which two organisms are more closely related to one another?

In both humans and starfish, the blastopore becomes our anus….

In insects, the blastopore becomes their mouth.

• Defined: the evolutionary history of a species• Cladograms used to show order in which species evolved from

their ancestor• Evidence from morphology, biochemistry, fossils, embryology

are used to build cladograms

Phylogeny

Earth cities

E. hemisphere

France

Italy

Dallas

Paris

Las Vegas

Rome

Quebec

Rio de Janeiro

W. hemisphere

S. America

N. America

Canada

USA

Nevada

Texas

Choices:ParisRio de JaneiroDallasQuebecLas VegasRome

Very broad

Less broad

Less broad

Less broad

Very specific

ParisRome

Rio de JaneiroDallasQuebecLas Vegas

DallasQuebecLas Vegas

DallasLas Vegas

Earth cities

E. hemisphere

France

Italy

Dallas

QuebecW. hemisphere

S. America

N. America

Canada

USA

Nevada

Texas

What does Dallas and Quebec have in common?

ParisRome

Rio de JaneiroDallasQuebecLas Vegas

DallasQuebecLas Vegas

DallasLas Vegas

Earth cities,W. Hemisphere,N. America

• Defined: the evolutionary history of a species• Cladograms used to show order in which species evolved from

their ancestor• Evidence from morphology, biochemistry, fossils, embryology

are used to build cladograms

Phylogeny

List the characteristics of a salamander.

JawsLungs

• Defined: the evolutionary history of a species• Cladograms used to show order in which species evolved from

their ancestor• Evidence from morphology, biochemistry, fossils, embryology

are used to build cladograms

Phylogeny

What does a mouse and lizard have in common?

1) What does an amphibian & crocodile have in common?

Vertebrae, Bony skeleton, Four limbs

2) List the traits of a ray-finned fish.

Vertebrae, bony skeleton, does not have 4 limbs

1 minute: Discuss

with your neighbor

These are the same cladograms in two different formats.

What does an amphibian & rabbit have in common?

How many of these 8 species have calcitic sclerites?

1 2 3 4 5 6 7

How many of these 8 species have a common coenchyme?

1 2 3 4 5

How many of these 8 species have eight fully developed mesenteries?

1 2

Review1) What is morphology and

how can it be used to help classify organisms?

2) What are homologous structures and how is it used to help classification?

3) How can molecular evidence like DNA and chromosomes be used to classify life?

4) What does it mean if two different organisms develop along similar pattern? Different patterns?

5) List the traits of birds.

6) What do birds and prosimians have in common?

7) Which trait separates insects from the rest?