Animal Biology Animals are split into two major groups: Vertebrates InvertebratesVertebrates These are animals with a backbone. There are five groups of vertebrates: Amphibians- Birds Fish- Mammals ReptilesAmphibians Have moist skin Lay jelly coated eggs in water Lives on land and water Birds Have feathers and hollow bones Lay hard shelled eggs Warm blooded Fish Have wet scales Lays eggs in water Lives in waterMammals Have hair and produce milk Give birth to live offspring (no eggs) Warm blooded Reptiles Have dry scales Lay leathery shelled eggs Cold blooded Invertebrates These are animals without a backbone There are eight groups of invertebrates Molluscs-Flatworms Annelids-Roundworms Sponges-Echinoderms Cnidarians- ArthropodsMolluscs Crawl on a single fleshy pad. Can have a shell Flatworms Have flat worm like bodies Annelids Have round worm like bodies Have bodies divided into segments Roundworms Have long thin round worm like bodies Have bodies with no segments Sponges Have bodies made of loosely joined cells Echinoderms Have bodies divided into five parts Have spiny outer covering Cnidarians Have thin sack like bodies Have tentacles Arthropods Have lots of legs and segmented bodies. There are four group of arthropods: Arachnids- Crustaceans Centipedes - Insects& MillipedesArthropods Arachnid Have four pairs of legs. Have bodies divided into two sections Arthropods Centipedes & Millipedes Have long thin bodies and pairs of legs on each of their many body sections Arthropods Crustacean Have five-seven pairs of legs First pair often used as pincers Bodies covered in shell Arthropods - Insects Have three pairs of legs Bodies divided into three sections Often have wings Characteristics of Animals Over a million different types have been identified! Kingdom Protista 1. Heterotrophy Cant make their own food must eat things.2. Multicellularity Made up of more then one cell! Although animals come in a wide range of sizes, the cell sizes are all very similar!3. Sexual reproduction Almost all animals reproduce sexually by producing gametes. Unlike the egg cells, the sperm cells of animals have a flagella and are highly mobile.4. Diploidy adults have two copies of each chromosome, one inherited from their father and one from their mother.5. Tthe absence of a cell wall Among the cells of multicellular organisms, only animal cells lack rigid cell walls. The absence of a cell wall has allowed animals mobility that other multicellular organisms do not have.6. Blastula formation In all animals except sponges, the zygote (fertilized egg cell) undergoes cell divisions that form a hollow ball of cells called a blastula.7. Cells organized as tissues Cells within the blastula eventually develop into three distinct layers of cells endoderm, ectoderm, and mesoderm . These layers are called the primary tissue layers because they give rise to all of the tissues and organs of the adult body.

tissues are groups of cells with a common structure that work together to perform a specific function.Body Symmetry All animals have their own particular body plan, a term used to describe an animals shape, symmetry, and internal organization.

1. Asymmetry: Animals that grow in an irregular pattern, such as a sponge, show asymmetry.2. Radial symmetry: Animals with radial symmetry have body parts arranged around a central axis. 3. Bilateral symmetry: Animals with bilateral symmetry have a distinct right and left half, and most display cephalization.

Body plans Animals have one of three basic body plans: acoelomate, pseudocoelomate, and coelomate.Coelom: a body cavity, coelom or (SEE luhm), a fluid-filled space found between the body wall and the digestive tract (gut). This space is lined with cells that come from mesoderm. Coelomates are either protostomes or deuterostomes. Protostomes (first mouth) are coelomates whose embryonic development shows a blastopore associated with a mouth. Deuterostomes (second mouth) are coelomates whose embryonic development shows a blastopore associated with an anus, with a second opening forming the mouth (hence "second mouth"). Acoelomate Animals with no body cavity are called acoelomate (ay SEEL oh mayts). The space between an acoelomates body wall and gut is completely filled with tissuesPseudocoelomate have a body cavity located between the mesoderm and endoderm. Their body cavity is called a pseudocoelom (false coelom)

Segmentation Segmentation in body structure underlies the organization of all advanced animals. Some animals have their bodies divided into segments. This allows them to specialize certain segments, such as for antennae, eyes, claws, etc. Humans, insects, and earthworms are examples of segmented animals.

Animal Body SystemsBody systems are specialized to carry out different tasks.Levels of organization:Cells tissues organs organ systems organisms Digestive systems Simple animals have a gastrovascular cavity with only one opening, while more-complex animals have a one-way gut.Respiration/ gas exchange Simple animals exchange gases directly through their skin. More-complex aquatic animals use gills, while terrestrial animals use a variety of respiratory organs, such as lungs.circulatory system In an open circulatory system, circulatory fluid leaves the vessels and enters the body cavity. In a closed circulatory system, blood remains in the vessels. open circulatory system -- primitive system found in insects and crustaceans -- blood not always contained in blood vessels -- heart pumps hemolymph (blood and cell fluids) into vessels, but vessels empty into large cavities or sinuses containing organs -- blood diffuses through tissues and back into heart. closed circulatory system -- found in higher animals -- system is "closed" because the blood is always contained in vessels.Nervous System While simple animals have little coordination among their nerve cells, complex animals have nerve cords and a brain with associated sensory structures.Excretory System For most animals, eliminating wastes is linked to maintaining the correct water balance in their body.Skeleton/Support Hydrostatic support Exoskeleton EndoskeletonAsexual reproduction Asexual reproductive methods include fragmentation, splitting in two, and parthenogenesis. Reproduction that does not involve the fusion of two gametes is called asexual reproduction. A sponge, for example, can reproduce by fragmenting its body. Each fragment grows into a new sponge. Some species of sea anemone reproduce by pulling themselves in half, forming two new adult anemonesSexual reproduction In sexual reproduction, male and female gametes combine to form a new individual