Kingdom Animalia

Review! ► Kingdom ► Phylum ► Class ► Order ► Family ► Genus ► Species

Review… Scientific Names ► The scientific name of an organism is made up of both its Genus and species name  E.g. Homo sapiens

Evolutionary relationships ► A cladogram or phylogenetic tree ► shows how closely related organisms are ► Closer together = more closely related!

A Cladogram for Invertebrates Protista Porifera Cnidaria Platyhelmintes (Worms) Mollusca Arthropoda Echinodermata Urochordata Chordata

First Life! ► Simple, unicellular organisms in the ocean. ► 2.5 billion years ago ► Carried out all life functions: eating, respiring, eliminating waste and reproduction.

Multicellular Life ► The first multicellular life, also in the oceans, began 600 million years ago ► How did it happen?

► Possibility 1: ► Unicellular protists lived together in a group ► They continued to stay together

► Possibility 2: ► During reproduction, the two cells did not separate completely ► They stayed living together

► Possibility 3: ► Protists with more than one nucleus started to have parts that did different jobs ► What do you think? How did multicellular life begin?

Level of Organization ► Multicellular organisms have specialized cells ► Cell – level  Each cell works on its own ► Tissue – level  Cells work together to do a job ► Organ – level  Tissues work together to do a job

3 Kinds of Symmetry 3 Kinds of Symmetry 1. No symmetry  Just a lump of stuff 2. Radial symmetry  In a circle  Can cut it any way through the center and have two equal halves 3. Bilateral symmetry  Two sides  Can only cut it in the middle to have two equal halves

► What are the simplest animals?  Invertebrates = Animals without a spine  Vertebrates = Animals with a spine ► Which ones are invertebrates?

Invertebrates…

► These are the main things you need to know about each animal we study:  Body symmetry  Level of organization (cell, tissue or organ)  Nervous system  How it eats / excretes  Reproduction methods  Defenses  Examples of animals  Special features Try it for a mammal…

Phylum Porifera The Sponges

Characteristics ► Symmetry: None ► Level of organization: cell (no tissues or organs)  No nervous system  No coordination between cells

Water flow in a sponge Water flows in the ostia (pores) in the side of a sponge through a porocyte and exits through the osculum at the top of the sponge.

► Inside the sponge choanocytes (collar cells) with flagella move the water through the sponge

► Mobility:  Sessile – they do not move ► Feeding:  Suspension feeding ► Food floating in water comes in ► Individual cells engulf the food ► Excretion:  Wastes diffuse out of cells and exit through the osculum ► Reproduction:  Budding (asexual)  Eggs / Sperm in the water (sexual)

► Support:  Sponges have a hard “skeleton” made of spongin and spicules

► Natural bath sponges are just the leftover spongin without cells

► Defenses:  Sponges produce bad-tasting chemicals  Spicules can be hard spines that make the sponge difficult to eat (e.g. glass sponges)

► Cool facts!  Some sponges can be put through a blender, squeezed through cloth, and then will reform a sponge if put together afterwards  They have amazing powers of regeneration

Sponge slideshow

Diver with a basket sponge

Barrel sponge – a good hiding spot!

Many ostia and oscula

Evolutionary Relationships ► Sponges are related to Protists ► Choanocytes (collar cells) that move water through the body of a sponge look like an ancient protist!  Which possibility on the beginning of multicellular life do you think is correct now?