Animelia

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 deuterostomes develop 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

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 Porifera

5,000 Species

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

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 bdelloid rotifers and their jaws.

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!!

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

Phylum Mollusca

Not all Mollusca have shells