KINGDOM ANIMALIA CHARACTERISTICS EUKARYOTIC MULTICELLULAR HETEROTROPHIC (by ingestion) MOVE AT SOME POINT IN LIFE (not all - sponges are sessile) DIGEST FOOD TO GET NUTRIENTS LACK CELL WALLS CHARACTERISTICS CONT. PRESENCE OF NERVOUS AND MUSCULAR TISSUE CAPABLE OF ASEXUAL REPRODUCTION IN LOWER FORMS AND SEXUAL REPRODUCTION IN HIGHER FORMS. 9 phyla we will concentrate on: Porifera sponges Cnidaria jellyfish, sea anemones, coral Platyhelminthes flatworms Nematoda roundworms Annelida earthworms Mollusca shelled animals Arthropoda insects, spiders Echinodermata spiny-skinned Chordata vertebrates (and others) BASIS OF CLASSIFICATION Though animals differ in their form and structure, there are some fundamental similarities in them such as: -arrangement of cells, -body symmetry, nature of coelom, -nature of body wall (diploblastic or triploblastic) -segmentation -presence or absence of notochord These features form the basis for the classification of animals TRENDS IN ANIMAL EVOLUTION LEVEL OF ORGANISATION CEPHALIZATION BODY SYMMETRY BODY CAVITY FORMATION 1
LEVEL OF ORGANISATION Cellular level of organization- in these animals, cells of the body form loose aggregates e.g sponges Tissue level of organization-in these animals, cells of the animal carrying out the same function are arranged in tissues Organ-sytem level of organization-in these animals, tissues are grouped together to form organs, each specialized for a particular function CEPHALIZATION CONCENTRATION OF SENSE ORGANS AND NERVE CELLS AT FRONT END OF BODY BODY SYMMETRY The arrangement of body parts around a central point or line determines symmetry Some animals are assymetrical and cannot be divided into two equal halvesalong any plane Some show radial symmetry where the animal is divided into two equal halves along any plane passing through the central axis e.g cnidarians, echinoderms BODY SYMMETRY CONT Others show bilateral symmetry where the body can be divided into identical left and right halves along anly one plane e.g anneleids, arthropods, chordates etc 3 TYPES OF BODY SYMMETRY Asymmetrical-no symmetry (ex, sponge) Bilateral- body plan in which single line can divide body into 2 equal parts Radial-body plan in which body parts repeat around center of body 2
ANATOMICAL TERMS Dorsal- top or back Ventral- bottom Anterior- head end that goes first Posterior- tail end that follows Lateral- along the side (lengthwise) ANATOMICAL TERMS Dorsal Anterior Posterior Ventral BODY WALLS ECTODERM Covers surface of the organism Forms outer covering ENDODERM Innermost germ layer Forms lining of digestive tract, liver, lungs MESODERM Located b/w ectoderm & endoderm Forms muscles & most organs BODY WALLS ECTODERM ENDODERM MESODERM BODY WALLS Two main types of body plans: Diploblastic relatively simple consisting of two layers of cells, an outer ectoderm and an inner endoderm a condition in which a third layer called the mesoderm develops. The mesoderm seperates the ectoderm from the endoderm 3
BODY CAVITY FORMATION ACOELOMATE- no body cavity b/w digestive tract and outer body wall ex. Platyhelminthes (flatworms) Acoelomate Fig. 32.4c BODY CAVITY FORMATION PSEUDOCOELOMATE- slight body cavity between the mesoderm and endoderm Ex. Nematoda (roundworms) Pseudocoelomate Fig. 32.4b BODY CAVITY FORMATION COELOMATE- body cavity forms and cushions organs, allows for growth of organs. Ex. Annelids (earthworm) Coelomate Fig. 32.4a 4
Animal feeding habits Herbivorous Carnivorous Omnivorous Parasitic HERBIVORES- eat vegetation such as plants CARNIVORES- eat other animals OMNIVORES- feed on both vegetation & other animals PARASITES- feed on living organisms usually destroying or injuring the host organism FEEDING ESSENTIAL FUNCTIONS OF ANIMALS RESPIRATION CIRCULATION EXCRETION RESPONSE MOVEMENT REPRODUCTION 5
Asymmetrical Single body cavity Pores filter feeders Not motile (sessile) Provide habitat for other animals Most primitive animal Phylum Porifera (sponges) Phylum Cnidaria (jellyfish, sea anemones, coral) Diploblastic animals (body wall with an outer ectoderm and inner endoderm) Radial symmetry Predators-feed on crustaceans Exhibit polymorphism individuals with specialized shapes and different functions Phylum Platyhelminthes (planarians, tapeworms, flukes) Cephalization- head and brain Acoelomate- no body cavity Flattened shape Incomplete digestive system (one opening) Some are parasites in digestive tract Also called nematodes Phylum Nematoda (roundworms) Round worms with pointed ends Complete digestive systemseparate mouth and anus (2 openings) Pseudocoelomate Some are free living, some are important plant and animal parasites Phylum Annelida (segmented worms) E.g. earthworms, leeches True coelom (Coelomate) Metameric segmentation Phylum Arthropoda (jointed legged animals) E.g insects, spiders and scorpions, shellfish (crustaceans). Coelomate Exoskeleton Metamorphosis Molting 6
Phylum Mollusca (shelled sometimes) E.g snails, slugs, clams, mussels, scallops, oysters, octopus and squid Variety in form Unsegmented Coelomates Phylum Echinodermata (spiny-skinned) i.e. sea stars = starfish. Coelomate Radial symmetry Predatory Phylum Chordata (includes the vertebrates) E.g. fish, sharks, amphibians, reptiles, birds, mammals, Coelomate A dorsal hollow nerve cord (spinal cord in vertebrates) Internal skeleton Phylum chordata cont A notochord (most vertebrates only have a notochord during development becomes the backbone in vertebrates) The end!! Questions..? 7