Introduction to the Animal Kingdom source

Which of these is an “animal”?

Answer: They are all animals! Characteristics of Animals: eukaryotic multicellular heterotrophic lack cell walls motile at some point in lifespan develop from a blastula early in lifecycle (hollow ball of cells) most reproduce sexually with diploid stage being dominant stage

Biology = study of life Physiology = Study of the functions of organs Anatomy = the structure of the organism/organs Zoology = study of animals

Animal Functions Feeding strategies: Herbivore = eats plants Carnivore = eats animals Omnivore = eats plants and animals Detritivore = feed on decaying organic material Filter Feeders = aquatic animals that strain food from water Parasite = lives in or on another organism (symbiotic relationship) Scavenger = eats things that have been killed

2. Respiration: Take in O2 and give off CO2 Lungs, gills, through skin, simple diffusion

3. Circulation: Very small animals rely on diffusion Larger animals have circulatory system

4. Excretion: 5. Response: Coordinate their activities with Primary waste product is ammonia 5. Response: Coordinate their activities with Receptor cells = sound, light, external stimuli Nerve cells => nervous system 6. Movement: * Most animals move

7. Reproduction: Most reproduce sexually = genetic diversity   Many invertebrates can also reproduce asexually to increase their numbers rapidly

Body Plan how animal’s parts are arranged and organized; structural blueprint Body Symmetry: Asymmetry - no pattern (corals, sponges) Radial Symmetry - shaped like a wheel (starfish, hydra, jellyfish) Bilateral Symmetry -  has a right and left side (humans, insects, cats, etc)

Identify the Symmetry

Body Sides anterior - toward the head posterior - toward the tail dorsal - back side ventral - belly side

Levels of Organization In multicellular organisms cells have become specialized to perform a specific function. Groups of specialized cells that work together are referred to as a tissue – there are 4 animal tissues (epithelial, connective, muscular, nervous) Groups of tissues can form organs. Organs can work together in systems – organ systems to carry out specific functions

Cephalization - an anterior concentration of sense organs (to have a head) *The more complex the animal becomes the more need for connection of nervous tissue and receptors at the anterior/head end of body to allow for rapid movement and processing stimuli Octopus – member of the class Cephalopoda (head-foot)

Segmentation "advanced" animals have body segments – repeating parts different segments like head, thorax, abdomen have become specialized for specific function

Embryological Development Early Development Animals begin life as a zygote (fertilized egg)

The cells in the zygote divide to form the BLASTULA - a hollow ball of cells

The blastula pinches inward to form three GERM LAYERS/body layers. Give rise to body systems i.e. circulatory, reproductive, excretory, muscular (outer) (middle) Give rise to outer skin and nerves. Give rise to gut. (inner)

Coelom – body cavity Digestive tract/gut with one or two openings; a tube system - develops mouth first - develops anus first

Limbs: legs, flippers and wings Animals with bilateral symmetry and cephalization also tend to have paired external appendages or limbs Limbs may be used for movement, defense or gathering sensory information. e.g. antennae, mouthparts, wings, gills, legs, fins, arms, and certain parts of a tail

Animal Kingdom Like plants the early ancestor of the animals moved from water onto land. Major evolutionary milestones are marked by changes in the body plan. There are about 35 animal phyla but 9 major ones. However one common way to group animals is whether they have a backbone – vertebrates = 5% or the absence of a backbone – invertebrates = 95%

Animal Kingdom Phyla Phylum Porifera – sponges Phylum Cnidaria – sea anemones, jellyfish, hydra

Phylum Platyhelminthes - flatworms Free-living Planarian Parasitic Tapeworm

Phylum Nematoda – roundworms Phylum Annelida – segmented worms

Phylum Mollusca – clams, squid, snails

Phylum Arthropoda – crustaceans, insects, spiders This is the largest phylum in the animal kingdom and contains the most number of species

Phylum Echinodermata - starfish

Phylum Chordata – includes all vertebrates

Phylum Rotifera –microscopic aquatic animal Soft bodies therefore fossil record weak Filter feeders – omnivorous – primary consumers Most reproduce by pathogenesis