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Animalia

Animalia: Evolutionary Origins

• Animals are heterotrophs

• All animals are consumers, and some are decomposers

• The first animals are thought to be descendants of protists

• Chordates that possess a backbone are called vertebrates; all other animals are invertebrates

What are the most ancient animals?What are the some recent to have evolved?

Review: The Linnaean System of Biological Classification

Domain……………………….Did

Kingdom……………………..King

Phylum……………………….Philip

Class……………..…………..Come

Order………………………….Over

Family………………………...For

Genus…………………………Great

Species……………………….Soup?

Animals: Embryo Development

• Embryonic cell layers generate all the different types of tissues found in adult bodies

• Protostomes and deuterostomesdevelop the digestive system in opposite directions

Animals: Symmetrical Bodies

• Most have symmetry

• Radial symmetry

– divides like a pie getting identical pieces

• Bilateral symmetry

– divides the body into two halves that mirror each other

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Animals: Organ Systems

• Most animals have organ systems

• Organs allow animals to function more efficiently

• Two or more organs working together form an organ system

Animals: Segmentation Enabled Division of Labor among Body Parts• Segmentation allows division of labor among body

parts

• Appendages are specialized body parts that arise from body segments and allow for evolutionary adaptations

Animals: Complexity of Body Cavities

• Body cavities allow an animal’s internal organs to grow freely and function independently

• Most body cavities also provide padding and protection for organs

• There are three types of body cavities found in animals:– Acoelomate– Pseudocoelomate– Coelomate

Shared Derived Traits of all Animals

• Animal cells lack a cell wall and are instead attached to an extracellular matrix

• Velcro-like patches of proteins called cell junctions allow animal cells to attach to each other

The First Invertebrates:Sponges, Jellyfish, and Relatives Sponge:

Phylum Porifera5,000 Species

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Sponges• Acoelomates

• Shared derived traits:– Filter feed

– No symmetry

– No tissue

– have “pores”

Do Sponges have Skeletons?!

All animals from now on have true tissues

Phylum Cnidaria• Cnidarians include

corals, sea anemones, and jellyfish

• Acoelomates

• Shared derived traits:– Radial symmetry

– A nerve network

– A lack of organs and organ systems

– Cnidocytes, stinging cells

– A mouth but no anus

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11,000 species

All animals from now on have bilateral symmetry

The Protostomes The Protostomes• Protostomes comprise the largest branch of the

evolutionary tree and range in size from microscopic to rotifers to the colossal squid

• Protostomes share the following characteristics– Development of the mouth from the embryonic

blastopore

– Cephalization-has a head

Phylum Rotifera• Rotifers are

important aquatic decomposers

• Shared derived traits:

– Cuticle

– Corona

• Scanning electron micrographs showing morphological variation of bdelloidrotifers and their jaws.

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Phylum Platyhelminthes:Flatworms and Flukes

• Flatworms can be free living or parasitic and lack respiratory and circulatory systems

• Acoelomates

• Often parasites

• Shared derived traits:

• 2 to 3 cells thick

• a “mouth” but no anus!

Tapeworms!

24 feet long tapeworm out of a mans intestine!

Tapeworms! Liver fluke!

Phylum Nematoda

• Also known as roundworms

• Examples: hookworms, pinworms

• Pseudocoelom

• Shared derived traits

– round worms

– full digestive tract (mouth, intestine, anus)

Hookworms!!

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All Animals from now on have a True Coelom

• Coelom – A fluid-filled cavity surrounding the digestive

tract and other internal organs

15,000 species

Annelida

Annelids: Segmented Bodies

• Full digestive tract, circulatory system

• Shared derived traits– Segmentation

allows division of labor among body parts

112,000 species

Mollusca

Phylum Mollusca

• The Mollusca is one of the most diverse phylum of animals and includes shellfish, snails, slugs, squid, and octopi

• Shared derived traits:– A muscular foot at the

base of the body– A compact grouping of

internal organs called the visceral mass

– A mantle enclosing the body cavity and the visceral mass

Mollusks Constitute the Largest Marine Phylum

• Bivalves hinged shell

• Most gastropods have a spiral shell

• Cephalopods thought to be the smartest invertebrates

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Phylum Mollusca

Not all Mollusca have shells

Phylum Arthropoda

1,000,000 species!!!!!

Phylum Arthropoda• More than a million

species

• Arthropods have a hard outer exoskeleton made of chitin

• Shared derived traits:

– Jointed appendages

– Exoskeleton that is shed

– A segmented body • Head

• Thorax

• Abdomen

Class Crustacea

• Crab, lobster, shrimp, barnacles, krill, crayfish

• Shared derive traits:

– 10 or more legs

– Usually water dwellers

Class Insecta• Shared derive traits:

– 6 legs

Class Arachnida• Mites, ticks, spiders, scorpions

• Shared derive traits:

– 8 legs

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Class Myriapoda• Millipedes and centipedes

• Shared derive traits:

– More than 10 legs

– Land dwellers

The Deuterostomes The Deuterostomes• Deuterostomes share the following

characteristics– Development of the anus from the embryonic

blastopore

Echinodermata

7,000 species

Phylum Echinodermata

• Examples: sea stars, sand dollars, urchins

• Shared derived traits:

– Pentameral (5 sided symmetry)

– Marine

– Water vascular system

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Phylum: Chordata• Shared derived trait:

–Notocord

Chordates have a Notochord• The notochord is a strong, flexible bar, which runs the

length of the animal and provides support for the body

• Notochords were the first "backbones" serving as support structures in chordates

All Animals from here on are Vertebrates

• Vertebrates have a vertebral column

• Vertebrates include fish, amphibians, reptiles, birds, and mammals

Fish

• Jawless fish evolved into hinged jaws that allowed for more efficient predation

• Class: Chondrichthyes

–Sharks and Rays

–Shared derived traits:

–Cartilaginous

–Hinged jaw

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Stout Infant fish

• Class: Osteichthyes

–Bony fish

–Shared derived traits:

–Bones

–Hinged jaw

Class Amphibia• Frogs and salamanders

• Shared derived traits:

– Semiaquatic

– 4 legs

– Larva in water• Ectotherms

– body temperature matches that of their environment

Class Reptilia

• Adapted to a drier environment

• A water-conserving excretory system

• Ectotherms

• Shared derived traits

– Skin covered in waterproof scales

– The amniotic egg, containing stored food and a waterproof shell. Allows them to reproduce in dry climates

Class Aves• Adapted for Flight• Feathers initially evolved

for warmth and eventually adapted for flight

• Birds are endotherms (warm-blooded)

• Shared derived traits• Feathers• Hollow bones• 2 legs

Class Mammalia

• Shared derived traits

– Hair on the body and endothermy

– Sweat glands

– Lactation

– Internal fertilization and parental care

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Mammals and Birds Can Live in Diverse Habitats Because They

Regulate Body Temperature

• Endothermy and hair allow mammals to colonize cold regions

Parental Care Contributed to the Success of Mammals