Animal Diversity Chapter 23

animal characteristics All animals share a unique set of derived characteristics. Animal cells are supported by collagen. three-stranded protein found in bone, skin, ligaments, fingernails, and hair

animal characteristics Animals are diploid and usually reproduce sexually. diploid parents produce diploid offspring Diploid cells have two copies of each chromosome: one copy from the mother and one from the father do not have free-living haploid life stages

animal characteristics Most animals have Hox genes. Hox genes tell embryonic cells which body part to become. Mutations in Hox genes led to the vast diversity of animal species. head tail fruit fly genes human HOX-B genes

animal phyla Vertebrates have an internal segmented backbone. Invertebrates do not have a backbone. Invertebrates encompass most animal groups.

Animal Classification Three criteria are used to categorize animals. body plan symmetry tissue layers developmental patterns gastrovascular cavity mouth mesoglea oral arms tentacles blood vessels brain hearts muscle segment nerve cord mouth digestive track

Animal Classification There are two types of body plan symmetry. bilateral symmetry: body divides equally along one plane Bilateral symmetry can be divided equally along only one plane, which splits an animal into mirror-image sides.

Animal Classification There are two types of body plan symmetry. Radial symmetry: body arranged in circle around a central axis Animals with radial symmetry have body parts arranged in a circle around a central axis.

ASYMMETRICAL Animals that have NO symmetry SPONGES

Body Surfaces Anterior – toward the head Posterior – toward the anus Dorsal – toward the spine (back) Ventral – toward the stomach (belly button) Lateral – to the side Oral – side where the mouth is located Aboral – side opposite the surface where the mouth is located  

Characteristics of Animals All multicellular Eukaryotes (cells with nucleus & organelles) Ingestive heterotrophs (take in food and internally digest it) Store food reserves as glycogen copyright cmassengale

Lions Feeding (Ingestion) copyright cmassengale

Support Systems Have some type of skeletal support Endoskeleton is internal 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 copyright cmassengale

Cicada Molting Exoskeleton copyright cmassengale

Support Systems Worms and echinoderms (starfish) have fluid-filled internal cavities giving them support Called hydrostatic skeletons copyright cmassengale

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 copyright cmassengale

SESSILE SEDENTARY Chiton Sponge MOTILE Cheetah copyright cmassengale

Reproduction in Animals All animals are capable of sexual reproduction Some animals like sponges and earthworms are hermaphrodites producing both eggs and sperm copyright cmassengale

Leeches Exchange Sperm During Mating copyright cmassengale

Reproduction in Animals Females of some animals produce eggs, but the eggs develop without being fertilized Called Parthenogenesis New offspring will be all female Parthenogenesis occurs in some fishes, several kinds of insects, and a few species of frogs and lizards copyright cmassengale

Parthenogenesis in the Komodo Dragon copyright cmassengale

Mating and Mating Behaviors Female Beetles Mating Young Courtship Male Mating and Mating Behaviors copyright cmassengale