The Animal Kingdom

Unifying Animal Concepts:

• 1. They are classified according to body plan, symmetry, number of germ layers, & level of organization.

• 2. There is an increase in complexity when groups are arranged in order from first evolved to most recent.

• 3. Animals are adapted to their way of life. (Active vs. inactive, aquatic vs. terrestrial)

Animal Characteristics

• Heterotrophic- have to take in food

• Generally have an active lifestyle

• Multicellular

• Organized cells into tissues, tissues into organs

2 Groups of Animals

• 1. Invertebrates: lack a dorsal backbone

2. Vertebrates: have a backbone made up of vertebrae

Animal Body Plans

• 1. Sac Plan: One opening for food intake and waste excretion.

• 2. Tube within a tube: one entrance for food, another exit for waste.

Animal Symmetry

• Asymmetry: No Particular Symmetry

• Radial Symmetry: Animal is organized circularly (like a wheel). Tend to be sessile. Why?– Can reach food in all directions around them!

• Bilateral Symmetry: definate left and right halves.

Animal Germ Layers

• Ectoderm: Outer

• Endoderm: Inner

These 2 form tissue level organization.

• Mesoderm: Middle

Animals with all 3 have organ level organization.

Internal Body Cavities

• Acoelomate: NO open space in which internal organs are located

• Coelomate: have a true Coelom - open space

Primitive Invertebrates

• Sponges

• Cnidarians

• Flatworms

• Roundworms

Classification

• Common Name: Sponge

• Scientific Name: Grantia

• Phylum: Porifera

• Class: Calcarea

• Other: 5,000 species; 150 species live in fresh water

SPONGES• Phylum: Porifera “Pore Bearer”• Body Plan: Sac; 2 cell layers with jellylike

mesophyll in between• Body Cavity: Acoelomate, hollow cylinder• Symmetry: Asymmetry• Cell Specialization: Collar Cells (Choanocytes) &

Amoebocytes; cell recognition• Other: most are marine, abundant in warm coastal

waters

Sponge Life Processes• Absorption: Collar cells with tiny flagella

draw water & food (plankton) into pores, digested by food vacuoles in cells

• Feeding: Sessile filter feeders

• Digestion: food vacuoles in cells

• Respiration: Water flowing through pores

Sponge Life Processes

• Circulation: Amoebocyte cells transport nutrients from cell to cell, physically move (crawl) within the body wall

• Excretion: Carbon dioxide & waste diffuse into water; Osculum = large opening on the top

• Secretion: Amoebocytes produce spicules and sex cells

Spicules

Light Microscope

Electron Microscope

Sponge Life Processes

• Response: None, no nervous system

• Movement: Adult = none; Larvae = ciliated and free swimming

• Reproduction: Hermaphrodite; Sexual - fertilization to form a zygote in the water (NO self fertilization!) = Ciliated Larvae Asexual - budding (gemmule formation during harsh conditions) & regeneration

Sponge Life Processes

• Support: Spicules = calcium carbonate & silica; very hard. Spongin = Protein; soft

Ecological Relationships

• Mostly Marine

• Food for snails, fish, starfish

Body Systems Compared to Humans

• Fertilization: Separate sperm and egg cells

Sponge Diagram

Question:• How much deeper would the oceans be if

sponges didn’t live there?

• Sponges drink about 64 glasses of water a day and some species filter almost 20,000 times their volume in a day.

• Worlds largest Sponge: Barrel Shaped Loggerhead Sponge = 4 ft. high; 3 ft. diam. Found in the West Indies & off of Florida

• Largest ever found = Wool Sponge 6 ft. in circumference

• Deepest Sponges = found at depths of up to 18,500 ft.

• In 1994, a “predatory” sponge was discovered in a Mediterranean cave near Marseilles, France, this sponge actually covers the prey and then consumes it.

• If part of a sponge breaks off, it can actually become a separate, thriving sponge.