The Animal Kingdom

• Define phylogenic tree-explain why scientists use them.

~General Characteristics ~

Multicellular-made up of more than one type of cell

Eukaryotic

Heterotrophs

~General Characteristics ~ Invertebrate- Does NOT possess or develop a vertebral column (backbone), derived from the notochord

• Vertebrate- Developes a vertebral column (backbone) from the notochord

–Hydrostatic Skeleton: Water supported skeleton

– Exoskeleton: hard outer covering made of chitin

– Endoskeleton: Made of bone or cartilage, inside of the body

• Body Cavity- fluid-filled space located between an animal’s outer covering (epidermis), and the outer lining of the gut cavity, where internal organs develop

• 1. Acoelomates – animals have 3 tissue layers with a digestive tract but no body cavities.

• 2. Pseudocoelomates – animals with a fluid-filled body cavity between the endoderm & mesoderm

• 3. Coelomates – animals with a body cavity completely surrounded by mesoderm.– They have space for internal organs to attach

~ Characteristics ~• Most animals develop from a zygote or

“fertilized egg.” The zygote goes through a series of cellular divisions to form a Blastula – a hollow ball of cells.

~ Developmental Characteristics ~• These cells will form into 3 tissue layers by a process called

gastrulation:– Ectoderm, a layer of cells on the outer surface of

the gastrula– Endoderm, a layer of cells lining the inner surface

of the gastrula– Mesoderm, made up of two layers of cells lying

between the ectoderm and endoderm – middle layer

~General Characteristics ~

Bilateral Symmetry

Radial Symmetry

Asymmetrical Symmetry

Open Circulatory System • the blood flows from the heart through open-ended

vessels into sinuses where it bathes the tissues inside the cavity. This is how gas exchange occurs.

Closed Circulatory SystemThe blood of a closed system always flows inside

vessels and is pumped around the entire body for gas and nutrient exchange.