Lost World

1.muticelled

2.heterotrophs

3.aerobic respiration

4.reproduce asexually and sexually

5.motile during part of life cycle

6.have stages of embryonic development

embryonic cells give rise to primary tissue layers called the ectoderm, endoderm and

usually mesoderm

these tissue layers give rise to all tissues and organs of body

7.eukaryotic

Body symmetry

May be radial symmetry or bilateral symmetry

Radial symmetry Ð'- all body parts arranged regularly around a central axis

Like spokes of a bike wheel

Ex. Hydra

Bilateral symmetry Ð'- have a right and left half that are mirror images of each other

Seen in more advanced animals

Cephalization Ð'- have concentration of sensory structures and nerves and brain region

In head area

Type of Gut

Gut Ð'- is a tubular or saclike region in the body in which food is digested, then absorbed into the internal environment

Saclike guts Ð'- have one opening for taking in food and expelling residues

Tubelike (complete) digestive system Ð'- has an opening at two ends called mouth

And anus

Different parts of system have specialized functions such as preparing, digesting

And storing materials

Types of Body Cavities

May be of three types: coelom, pseudocoel, acoelomate

Acoelomate- tissues fill in region between gut and body wall

No coelom

pseudocoel Ð'-body cavity with no peritoneal lining

Example:

Coelom Ð'- area between gut and body wall with unique tissue lining called ___________

Lining encloses organs and helps hold them in place

Advantage: favors increase in size and activity by

Segmentation

repeating series of body units that may or may not be similar to one another

Ex.earthworms

Ex.insects

We will study the animals by the phyla. All are Kingdom Animalia.

Phylum Porifera

Ex.

Body plan

Germ layers:

Symmetry:

Cephalization:

Gut:

Coelom:

Segmentation:

Endoskeleton: skeleton on inside of body

may be composed of spicules, tough fibers or both

Fibers made of spongin which is a protein

Spicules are sharp and made of calcium carbonate or silica

Skeleton reason sponges have been successful

Sessile

Other characteristics: filter feeder

Water flow through sponge functions to:

Ostium

Central cavity - spongocoel

osculum

collar cells Ð'- line central cavity, have flagella that beat to set up current

trap food for sponge, sponges like to eat

Reproduction

May be sexual or asexual

Sexual-produce both eggs and sperm in same sponge

Sperm released into water through osculum

Sperm enter ostia of neighboring sponge

Eggs retained and fertilized in spongocoel

Zygote leaves through osculum= swimming larvae

Larvae swim away

Larvae go to new location, attach to substratum, develop into adult sponge

Asexual-fragmentation

Part breaks away from parent and grows to new sponge

Phylum Cnidaria

Have cnidocytes or stinging cells

Ex.

Body plan:

Germ layers: diploblastic

Symmetry:

Cephalization:

Gut: sac-like with gastrovascular cavity GVC

Two functions of gut: digestion of food

Circulation of food, oxygen, waste

Coelom:

Segmentation:

Skeleton: none usually

Exoskeleton in coral

Exoskeleton on outside of body

Other Characteristics:

Tentacles Ð'-

Likes to eat

All cnidarians