3.3 The Animals Learning Goals: Describe some of the key features used to classify animals (presence of nervous system, radial symmetry/bilateral symmetry, protostome/deuterostome, vertebrate/invertebrate, number of germ layers, presence of coelom) Identify the main groups of chordates and describe their distinguish features

General Characteristics of Animal Multicellular Heterotroph Typically reproduce sexually Lack cell wall Motile during some life stage (i.e. stationary sponges have free-swimming larval stages) Rapid response to external stimuli Have two types of tissues only found in animals: nervous tissue (brain, nerves and spinal chord) and muscle tissue

The central theme to Kingdom Animalia is that over evolutionary time, animals have increased in complexity. There are different stages leading to complexity: Level of cellular organization and specialization Type of symmetry of body plan Degree of cephalization Presence, type of body cavity (coelom) Presence of segmentation Structure of digestive system

Types of Tissues

Presence of a Body Cavity If fluid is present between the body wall and the digestive tract it is referred to as a coelom (body cavity) This body cavity is lined with the mesoderm, which produces compartments in the body (meaning nutrients and oxygen don’t diffuse into all body cells)

Advantages of a Coelom Acts as a cushion for internal organs Provides more room for internal organs to expand Allows animal to become larger Allows digestive tract to develop specialized regions and formation of blood vessels

An Animal’s Body Plan Type: Asymmetrical Lack symmetry Type: Spherical Can be divided by equal halves by a plane passing in any direction through a central point.

An Animal’s Body Plan Type: Radical Can be divided into equal halves by a plane passing through the central axis in any direction Type: Bilateral Can be divided into equal halves only along a single plane Organisms with bilateral symmetry exhibit cephalization

Cephalization Concentration of sensory organs and nerve cells at the anterior end Act as a control centre Allows organism to respond to stimuli quickly Evolutionary favoured

Animal Diversity Porifera (sponges) cnidaria

Animal Diversity Platyhelminthes (flat worm) Nematoda (round worms) Annelida (segmented)

Animal Diversity mollusca echinodermata

Animal Diversity crustaceans arachnida insecta Diploda / chilopoda

Animal Diversity Tunicates + lancelets Jawless fish Cartilage fish Bony fish Amphibians Reptilia Aves Mammalia

The Worms

The Worms

The Worms

The Worms

The Worms

The Worms

The Worms

The Worms

The Worms

Homework Review for Unit 1 Test (Monday Jan. 23, 2017)