Wednesday, September 5

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Chapter 32Introduction to Animal Evolution
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Chapter 32Introduction to Animal Evolution
What is an animal?
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular
heterotrophic
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular heterotrophic
eukaryotes
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular heterotrophic eukaryotes
ingest their food
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular heterotrophic eukaryotes ingest
their food
no cell walls
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Chapter 32Introduction to Animal Evolution
What is an animal?
multicellular heterotrophic eukaryotes ingest
their food no cell walls
nervous tissue
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Chapter 32Introduction to Animal Evolution
What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue

muscle tissue
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Chapter 32Introduction to Animal Evolution
What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue

blastula stage
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Chapter 32Introduction to Animal Evolution
What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage

gastrula stage
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Chapter 32Introduction to Animal Evolution

• What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage
• gastrula stage

embryonic tissue layers
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Chapter 32Introduction to Animal Evolution

• What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage
• gastrula stage
• embryonic tissue layers

Hox genes
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Chapter 32Introduction to Animal Evolution

• What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage
• gastrula stage
• embryonic tissue layers
• Hox genes

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Chapter 32Introduction to Animal Evolution

• What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage
• gastrula stage
• embryonic tissue layers
• Hox genes

Animals probably evolved from a colonial,
flagellated protist.
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Chapter 32Introduction to Animal Evolution

• What is an animal?

• multicellular
• heterotrophic
• eukaryotes
• ingest their food
• no cell walls
• nervous tissue
• muscle tissue
• blastula stage
• gastrula stage
• embryonic tissue layers
• Hox genes

Animals probably evolved from a colonial,
flagellated protist.
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Chapter 32Introduction to Animal Evolution
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Chapter 32Introduction to Animal Evolution

• Phylogenetic trees are always being revised.

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Chapter 32Introduction to Animal Evolution

• Science is different from other ways of knowing
• Even our most cherished ideas in science are
  probationary
• Ideas can be falsified through experiments or
  observation
• The more testing a hypothesis withstands, the
  more credible it is
• Its all about the evidence.

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Chapter 32Introduction to Animal Evolution

• The old system

Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Deuterostome
Protostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Deuterostome
Protostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Deuterostome
Protostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Deuterostome
Protostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
31
Chapter 32Introduction to Animal Evolution

• The old system

Deuterostome
Protostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
32
Chapter 32Introduction to Animal Evolution

• The old system

Protostome
Deuterostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Protostome
Deuterostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Protostome
Deuterostome
No body cavity
Body cavity
Each of the four main branches divides the tree
into grades based on body plan.
Radial symmetry
Bilateral symmetry
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The old system

Protostome
Deuterostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
Molecular evidence has rearranged the branches.
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The new system

Protostome
Deuterostome
No body cavity
Body cavity
Radial symmetry
Bilateral symmetry
Molecular evidence has rearranged the branches.
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The new system

Protostome
Deuterostome
Radial symmetry
Bilateral symmetry
Molecular evidence has rearranged the branches.
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The new system

Deuterostome
Protostome
Radial symmetry
Bilateral symmetry
Molecular evidence has rearranged the branches.
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• The new system

Lophotrochozoa (tentacles)
Ecdysozoa (exoskeletons)
Deuterostome
Protostome
Radial symmetry
Bilateral symmetry
Molecular evidence has rearranged the branches.
No true tissues
True tissues
Ancestral colonial choanoflagellate
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Chapter 32Introduction to Animal Evolution

• Most animal phyla originated in the Cambrian
  explosion between 525 million and 565 million
  years ago.

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Chapter 32Introduction to Animal Evolution

• Most animal phyla originated in the Cambrian
  explosion between 525 million and 565 million
  years ago.
• Evolution was so fast during that period that it
  is difficult to sort out the history.

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological The development of predator-prey
  relationships

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological The development of predator-prey
  relationships
• Geological

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological The development of predator-prey
  relationships
• Geological Increasing levels of atmospheric
  oxygen

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological The development of predator-prey
  relationships
• Geological Increasing levels of atmospheric
  oxygen
• Genetic

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Chapter 32Introduction to Animal Evolution

• Causes of the Cambrian explosion
• Ecological The development of predator-prey
  relationships
• Geological Increasing levels of atmospheric
  oxygen
• Genetic Changes in the Hox genes which control
  embryonic development.

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Chapter 32Introduction to Animal Evolution

• Three Germ Layers
• and the
• Coelom

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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
ectoderm mesoderm endoderm
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
ectoderm mesoderm endoderm
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution
acoelomate
pseudocoelomate
ectoderm mesoderm endoderm
anus mouth
mouth anus
coelomate protostome
coelomate deuterotostome
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Chapter 32Introduction to Animal Evolution