Introduction to the Animal Kingdom

Introduction to the Animal Kingdom Animals are multicellular eukaryotic heterotroph whose cells lack cell walls Vertebrates: 5% of animal species with backbones Invertebrates: 95% of animal species WITHOUT backbones Cell specialization – specific cells perform specific jobs to get all the work in the body done

In Order to Survive, Animals Must: Feed – Carnivores – eat other animals Herbivores – eat plants Omnivores – eat other animals and plants Parasites – inside or on other organisms and do them harm Filter feeders – strain food from water Detritus feeders – feed on dead organic matter

In Order to Survive, Animals Must: Respire – Consume oxygen and give off CO2 Skin, gills, lungs

In Order to Survive, Animals Must: Circulate/Internal Transport – Must carry O2, nutrients and waste products to and from internal cells Heart and blood vessels in larger animals Smaller animals rely on diffusion

In Order to Survive, Animals Must: Excrete – Small animals – diffusion Larger animals – excretory systems (that can include complex kidneys)

In Order to Survive, Animals Must: Respond – Nerve cells – brain Gather information from environment Varies greatly from phylum to phylum

In Order to Survive, Animals Must: Move – Sessile – one spot, no movement Motile – move, muscles and/or skeletons

In Order to Survive, Animals Must: Reproduce – Mainly sexual, but invertebrates can also reproduce asexually Live birth or eggs Direct Metamorphosis – young look like adult Indirect Metamorphosis – young → metamorphosis → adult

Direct Metamorphosis Direct – young look like adult

Indirect Metamorphosis Indirect – young → metamorphosis → adult

Animal Evolution Complex animals tend to have high levels of cell specialization and internal body organization, bilateral body symmetry, a front end, or head, with sense organs, and a body cavity.

Cell Specialization Cell → tissue → organ → organ system → organism Ex. Stomach cell → stomach tissue → digestive system (mouth, stomach, intestines, etc) → all organ systems put together

Body Symmetry Asymmetrical – no symmetry (sponges) Radial symmetry – body parts repeat around center of body (simple animals – sea anemone and starfish) Bilateral symmetry – body can be divided into two equal halves – left and right sides Anterior – front end Posterior – back end Dorsal – upper side Ventral – lower side

Body Symmetry Bilateral Symmetry Radial Symmetry Posterior end Dorsal side Anterior end Plane of symmetry Planes of symmetry

Cephalization Complex animals concentrate sense organs and nerve cells in the anterior end of the body, this is called cephalization Ganglia – small clusters of nerve cells (simple animals) Brain – clusters of ganglia (more complex animals)

Introduction to Invertebrates