Introduction to animals Introduction to Animals
Traits
Characteristics of Animals All multicellular (metazoans) Eukaryotes (cells with nucleus & organelles) Ingestive heterotrophs (take in food and internally digest it) Store food reserves in the liver as glycogen
Lions Feeding (Ingestion)
Support Systems Have some type of skeletal support Endoskeleton inside and made of cartilage &/or bone Exoskeletons found in arthropods –Cover the outside of the body –Limit size –Must be molted making animal vulnerable to predators
Cicada Molting Exoskeleton
Support Systems Worms and echinoderms (starfish) have fluid-filled internal cavities giving them support Called hydrostatic skeletons
Movement Animals such as sponges may be sessile (attached & non-moving) Animals that move very little are said to be sedentary (clam) Animals that can move are motile Have muscular tissue to provide energy for movement
SESSILESEDENTARY MOTILE Sponge Chiton Cheetah
Reproduction in Animals sexual reproduction Some like sponges and earthworms are hermaphrodites produce eggs and sperm may exchange sperm and NOT fertilize their own eggs
Leeches Exchange Sperm During Mating Mating leech
Reproduction in Animals Females of some animals produce eggs, but the eggs develop without being fertilized Called Parthenogenesis New offspring will be all female occurs in some fishes, several insects, and frogs and lizards
Parthenogenesis in the Komodo Dragon
Mating and Mating Behaviors Beetles Mating Male Female Young Courtship
Levels of Organization Sponges =ONLY animals with just cellular level All others show– cell, tissue, organ, and system Cells may specialize (take own different shapes and functions) Cells held together by cell junctions to form tissues
Atom Molecule or compound Organelle CELL Levels of Organization Tissue Organ Organ system Organism Life begins
Invertebrate groups
Characteristics of Invertebrates Simplest animals greatest number of different species Most aquatic (found in water) NO backbone Includes sponges, cnidarians, flatworms, roundworms, annelids, mollusks, arthropods, and echinoderms
Sponge - Porifera Osculum of Sponge
20 Sponges and Cnidarians
Sea Anemone - Cnidaria Tentacles of Sea Anemone
More Cnidarians Brain Coral Red jellyfish
23
Flatworms - Platyhelminthes Planarian Marine Flatworm
Roundworms (Nematoda) and Segmented Worms (Annelida) Nematode Leech (segmented worm)
Mollusca (With and Without Shells) snailscallop nautilus sea slug octopus
Arthropoda (insects, spiders, crustaceans, horseshoe crab) Dung beetle Horseshoe crab crayfish spider
Echinoderms Sea cucumber Sand dollar starfish Brittle star Sea fan (crinoid)
Vertebrate Groups (Phylum Chordata, Subphylum Vertebrata)
Vertebrata More complex backbone of vertebrae simplest phylum to most complex: fish, amphibians, reptiles, birds, and mammals
Vertebrate Backbone
Vertebrata endoskeletons (internal) Some have skeletons of cartilage (sharks, rays, and skates)
Bone & Cartilage in Fetus
Fish lancelet ray anglerfish damselfish
Amphibia toad newt frog salamander
Reptilia Turtle Snake Alligator Lizard
37 Reptiles
Birds - Aves hummingbird ostrich lovebirds
Mammalia
Body Areas
Surfaces Dorsal – back Ventral – belly Anterior –front end Posterior –hind end Oral surface–mouth Aboral surface–opposite the mouth
DORSAL VENTRAL Surfaces (Most Animals) ANTERIOR POSTERIOR
Surfaces (Echinoderms) ORAL ABORAL mouth
Symmetry
Body Symmetry
Symmetry = arrangement of body parts around central axis Asymmetry
Body Symmetry Radial symmetry = body parts arranged around central point like spokes (echinoderms) –Most with radial symmetry are sessile (attached) or sedentary (move very little)
Body Symmetry Bilateral symmetry = divided into equal halves right and left sides are mirror images More complex
Body Symmetry bilateral symmetry, usually motile anterior and posterior ends Show cephalization concentration of sensory organs on the head
Segmentation
Segmentation Earthworms show external segmentation Humans show internal segmentation (backbone) Segments may fuse (cephalothorax)
Segmentation cephalothorax
Tissues
Tissue Development Zygote (fertilized egg) undergoes rapid cell divisions =cleavage Forms a hollow ball of cells =blastula
Blastula The blastocoel = center cavity of blastula with 1 germ layer (blastoderm)
Tissue Development folds inward at one point =Gastrulation opening =blastopore blastopore Archenteron
Tissue Development Blastopore may become mouth (Protostome) or anus (Deuterostome) Protostomes (mollusks, arthropods, & annelids) Deuterostomes (echinoderms & vertebrates) Some animals form a middle germ layer called mesoderm
Embryonic Development
Germ Layers NOT present in sponges Ectoderm (outer) – forms skin, nerves, sense organs Endoderm (inner) – forms liver and lungs Mesoderm (middle) – forms muscles & other systems
Body Layers All worms, mollusks, arthropods, echinoderms, and vertebrates have three cell layers –Ectoderm –Endoderm –mesoderm
Stages of Development
Larval Forms Animals with Indirect development Larva does NOT resemble adult Cnidarian larva = Planula
Larval Forms Mollusk (squid & octopus) larva = trochophore Echinoderm (starfish) larva is = Dipleurula
Metamorphosis Usually found in arthropods May be complete or incomplete Incomplete Metamorphosis: egg nymph adult Complete Metamorphosis: egg larva pupa adult
Metamorphosis COMPLETE INCOMPLETE
Body Cavities
Coelom - Body Cavity Internal body cavity fully lined with mesoderm Body organs suspended in this cavity
Coelom - Body Cavity Acoelomate =solid bodies filled with cells Ex.sponges, cnidarians, & flatworms
Coelom - Body Cavity Pseudocoelomate = (roundworms) = functional body cavity NOT fully lined with mesoderm
Animal Systems
Support Systems Spongin & spicules (sponges) Limestone cases (corals) Exoskeletons of Chitin (arthropods) –Must be shed or molted to grow Inner Calcium plates (echinoderms) Bone/cartilage endoskeleton (vertebrates)
Digestive Systems All animals = ingestive heterotrophs Gastrovascular cavity with one opening in cnidarians & flatworms = two-way digestive system
Two-Way Digestion
Digestive Systems one-way digestive system = mouth and an anus Includes annelids, arthropods, & vertebrates
One-Way Digestion Mouth anus
Circulatory Systems Transports oxygen & nutrients to cells Carries away wastes & carbon dioxide from cells Sponges, cnidarians, & flatworms do NOT have circulatory systems
Circulatory Systems In closed circulation, blood remains inside blood vessels until it reaches cells (annelids & vertebrates) In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity or hemocoel (arthropods & mollusks)
Open Circulation Closed Circulation