The Animal Kingdom Of all the kingdoms of

The Animal Kingdom • Of all the kingdoms of organisms, the animal kingdom is the most diverse in appearance. • So…. What Is an Animal?

• • • Animals are Multicellular. Animals are Eukaryotic heterotrophs. Animal cells lack cell walls. Animals belong to the kingdom Animalia. Animals must ingest food. Animals are capable of moving around.

Animals carry out the following essential functions… • Feeding and digestion (takes place in cells and in a digestive tract) • Respiration (gills, lungs, skin) • Circulation (open and closed systems) • Excretion • Response to outside stimuli • Movement • Reproduction

There are 9 animal phyla. • Invertebrates are animals without backbones. 8 of the animal phyla consist of invertebrates. • Vertebrates are animals with backbones. Only 1 animal phylum consists of vertebrates.

1. PORIFERA: SIMPLEST ANIMALS NO TISSUE LAYERS EXAMPLES: SPONGES

2. CNIDARIA HOLLOW BODY HAVE STINGING CELLS TWO BODY FORMS MEDUSA & POLYP EXAMPLES: CORAL, JELLYFISH, SEA ANEMONE

3. PLATYHELMINTHES: EXAMPLES: PLANARIA, FLUKE, TAPEWORM UNSEGMENTED WORMS FLAT WORMS

4. NEMATODA UNSEGMENTED WORMS ROUND WORMS EXAMPLES: HOOKWORMS, HEARTWORMS

5. ANNELIDA SEGMENTED WORMS MOST ADVANCED WORMS EXAMPLES: LEECH, EARTHWORMS

6. ARTHROPODA Invertebrate animals with exoskeletons made of chitin, a series of paired/jointed legs, and segmented body parts. Examples: Crustaceans (lobsters and crabs) Insects Arachnids

Characteristics of Arthropods • Open circulatory system: blood is pumped through a tubelike heart and into the body cavity (not contained in veins and arteries) • Molting: they shed old exoskeletons and grow new ones (see p. 732) • Insects undergo metamorphosis: incomplete or complete metamorphosis (see p. 744)

Incomplete Metamorphosis: process by which immature arthropods look similar to their adult form. Each time they molt, they become more and more like adults. In the last few stages of molting, they grow wings and sex organs.

Complete metamorphosis: process by which immature organisms change their body form before becoming an adult. Egg→ larvae → pupa →adult.

Arachnid

7. MOLLUSCA Mollusks have a complete digestive tract (consists of two openings: mouth and anus). They include gastropods, bivalves, and cephalopods. EXAMPLES: SNAIL, SCALLOP, OCTOPUS, MUSSELS

8. ECHINODERMATA HAVE A DERMAL SKELETON WITH SPINES & PLATES ONLY LIVE IN MARINE ENVIRONMENT EXAMPLES: SEA URCHIN, SEASTAR, BRITTLE STAR

9. CHORDATA (vertebrates) EXAMPLES: FISH, AMPHIBIANS , REPTILES, BIRDS, MAMMALS

Characteristics of Chordates (vertebrates) • Even though they are all very different, all chordates share the following 4 features at some stage of their development: 1. notochord: a flexible skeletal support rod embedded in the animal’s back 2. hollow nerve cord: runs along the animal’s back 3. pharyngeal slits: slits through the body wall in the pharynx (part of the gut immediately beyond the mouth). We have these as embryos. 4. tail: extends beyond the anal opening.

Other common characteristics… • • Endoskeletons Braincase Vertebrae Bones

All about fish…(p. 763 -767) • • • Vertebrates with gills and paired fins Live in the water Cold blooded 2 chamber hearts (1 atrium and 1 ventricle) Breathe through gills

All about amphibians…(p. 773777) • First tetrapods (animals with 4 limbs) • 3 chambered hearts (2 atria and 1 ventricle) • Need a source of water to reproduce

All about reptiles…(p. 793 -797) • Amniotic eggs: almost completely waterproof; prevent embryo from drying out • Covered in scales or plates • Live on land • Oviparous or viviparous • Cold blooded • 3 chambered hearts (2 atria and 1 ventricle) • Breathe with lungs

All about birds…(p. 798 -803) • • Evolved from dinosaurs Hollow bones (helps them fly) Amniotic eggs Breathe through lungs (air sacs are also located throughout their bodies-these are attached to the lungs) • 4 chambered hearts (2 atria and 2 ventricles)

All about mammals…(p. 805809) • • Hair or fur Mammary glands A middle ear containing 3 bones Jaws that allow them to chew food Warm blooded Breathe through 2 lungs 4 chambered hearts (2 atria and 2 ventricles)

More about mammals… • 3 types: 1. monotremes: mammals that lay eggs 2. marsupials: mammals that give birth to immature, underdeveloped live young that grow to maturity in a marsupium, or pouch 3. eutherian mammals: give birth to live young that have completed fetal development