Lecture 021 Animal Body Plans

Criteria for Evolutionary Development & Classification Cellular organization Symmetry Coelom Digestive system Segmentation Cephalization

Kingdom Animalia Symmetry Unorganized Radial Bilateral Cellular organization Tissues, organs, systems

Kingdom Animalia coelom Coelom Body cavity or not Digestive system digestive tube Coelom Body cavity or not Digestive system None, 1 or 2 openings, how

Kingdom Animalia Segmentation Repetition of body parts Cephalization Development of a “head end”

What to Remember Match with common name General characteristics Special evolutionary features General evolutionary location

Geologic Time Scale end of dinosaurs 1st dinosaur 1st reptiles Millions of Years end of dinosaurs 1st dinosaur 1st reptiles 1st amphibians 1st land plants 1st fish 1st invertebrates

Ediacaran Fauna: distinctive group of fossils dating from and existing only during Precambrian time 600 mya Australia's Ediacara Hills Environment: shallow seas Description: soft bodies; worms, cnideria May be an evolutionary dead end

Reconstruction of the sea floor during the Vendian times when the Ediacaran organisms thrived

Ediacaran Fauna (600-540 MYBP) end of Precambrian era

Ediacaran Seas Sea pens Mostly cnidarians and worms

Ancient Seas at the During the Cambrian Radiation (540 MYBP) Burgess Shale

Ancient Seas at the During the Cambrian Radiation (540 MYBP) Drawings based on fossils collected from Burgess Shale in British Columbia, Canada

Burgess Shale Fauna (540 MYBP) Feeding tentacles Hallucigena spines Similar to a sea urchin An explosion of body plans

Burgess Shale Fauna (540 MYBP) Pikaia- earliest known chordate

Burgess Shale Fauna (540-530 MYBP Anomalocaris Burgess Shale Fauna (540-530 MYBP Opabinia Wiwaxia

Living Invertebrates

Phylogentic Relationships of Animals Platyhelminthes Porifera Mollusca Chordata Arthropoda Annelida Cnideria Nematoda Echinodermata pseudocoelom segmentation acoelom Protostome: schizocoelem Deuterostomes: eucoelom radial symmetry bilateral symmetry no true tissues true tissue Ancestral Protist

Early Embryonic Development of an Animal

Major Stages of Animal Development gametogenesis fertilization cleavage blastula gastrulation differentiation and morphogenesis

Hypothetical Scheme for the Origin of Multicellularity in Animals

Protostome vs Deuterostome Blastula Protostome: blastopore becomes mouth Deuterostome: blastopore becomes anus Blastopore

What is a Phylum?

Some Examples of Animal Phyla Phylum Cnidaria sea anemones, corals, jellyfish, man-of-wars & hydroids Phylum Mollusca snails, slugs, chitons, clams, oysters, octopods & squids Phylum Arthropoda spiders, scorpions, crabs, shrimp, insects & centipedes Phylum Echinodermata sea stars, sea urchins, sea cucumbers & sea lilies Phylum Chordata sea squirts, fish, amphibian, reptiles, birds & mammals

Phylum Chordata

Major Body Plan Characteristics of Animals Symmetry Primary Germ Layers Gut Organization Body Cavity Segmentation Skeletal Systems Circulatory Systems Appendages Coloniality

Symmetry Asymmetry Radial Symmetry Bilateral Symmetry                                                      

Symmetry Bilateral Symmetry Radial Symmetry

Jellyfish Phylum Cnidaria Radial Symmetry Jellyfish Phylum Cnidaria

Pentamerous Radial Symmetry Sea Stars Phylum Echinodermata

Bilateral Symmetry Slug Phylum Mollusca

Bilateral Symmetry Squid Phylum Mollusca

Primary Germ Layers None Diploblastic Triploblast Mesoderm gut Ectoderm Endoderm

Fates of the Primary Germ Layers Ectoderm hair, nails, epidermis, brain, nerves Mesoderm notochord (in chordates), dermis, blood vessels, heart, bones, cartilage, muscle Endoderm internal lining of the gut and respiratory pathways, liver, pancreas

The Formation of Primary Germ Layers

The Formation of Primary Germ Layers

Germ Layer Patterns Endoderm Diploblastic gut Ectoderm

Diploblastic- two germ layers Phylum Cnidaria

Germ Layer Patterns Triploblastic: 3 germ layers Mesoderm gut Ectoderm Endoderm acoelomate

Gut Organization No Gut Blind Sac Gut Complete Gut

Sponges Phylum Porifera No Gut Sponges Phylum Porifera

Sponges Phylum Porifera No Gut Sponges Phylum Porifera

Blind Sac Gut Phylum Cnidaria

Complete Gut

Body Cavities Acoelomate Eucoelomate Pseudocoelomate

Body Cavities Acoelomate- lacks cavity between gut and outer body wall Mesoderm Acoelomate- lacks cavity between gut and outer body wall gut Ectoderm Endoderm

Body Cavities Eucoelomate- body cavity completely lined with mesoderm gut Ectoderm Endoderm

Body Cavities pseudocoelom Mesoderm Pseudocoelomate: body cavity partially lined with mesoderm gut Endoderm Ectoderm

Advantages of a Fluid-Filled Body Cavity hydrostatic skeleton greater freedom for internal organs greater body size because of body fluid circulation

Segmentation

Centipede Phylum Arthropoda Segmentation Centipede Phylum Arthropoda

Lobster Phylum Arthropoda Segmentation Lobster Phylum Arthropoda

Skeleton

Functions of the Skeleton supports basic body form protection of soft internal tissues and organs facilitates locomotion

Hydrostatic Skeletons Hard Skeletons Exoskeletons Endoskeletons

Sea Anemone Phylum Cnidaria Hydrostatic Skeleton Sea Anemone Phylum Cnidaria

Hydrostatic Skeleton: A non compressible fluid held under pressure in a closed body compartment. Uses antagonistic muscles for movement. The gastrovascular cavity of the jellyfish acts as hydrostatic skeleton against which contractile cells can work.

Earthworm Phylum Annelida Hydrostatic Skeleton Earthworm Phylum Annelida

Chiton Phylum Mollusca Exoskeleton Chiton Phylum Mollusca

Stony Coral Phylum Cnidaria Exoskeleton Stony Coral Phylum Cnidaria

Endoskeletons Vertebrates Phylum Chordata

Types of Appendages

Functions of Appendages locomotion feeding sensory protection

Sea Anemone Phylum Cnidaria Tentacles Sea Anemone Phylum Cnidaria

Jointed Appendages Bee Appendages Phylum Arthropoda

Circulatory Systems

Functions of Circulatory Systems transport of nutrients and metabolic wastes maintains water and solute balance defense against pathogens

Circulatory System None (simple diffusion) Body Cavity Circulation Closed Circulatory System Open Circulatory System

Comb Jelly Phylum Ctenophora No Circulatory System Comb Jelly Phylum Ctenophora

Circulation in a Moon Jellyfish Phylum Cnidaria

Closed Versus Open Circulatory Systems

Nervous Systems

Functions of Nervous systems integration of animal behavior processing and interpretation of sensory information elicits external and internal responses

Types of Nervous Systems

Coloniality

Coloniality Coral Phylum Cnidaria

Sea Fan Phylum Cnidaria Coloniality Sea Fan Phylum Cnidaria

Man-of-War Phylum Cnidaria Coloniality Man-of-War Phylum Cnidaria

Polymorphism in the Portuguese Man- of-War