Biology: Animal Kingdom, Invertebrates, and Mollusks Overview

Animal Kingdom

eukaryotic, multicellular organisms that lack cell walls and are heterotrophic because they ingest food

Invertebrate

animals lacking a backbone

Porifera

sponges; the most primitive animals

Sessile

attached and does not move

Filter feeders

organisms that get nutrients by filtering water

Collar cells

specialized sponge cells used for filtering water

Budding

asexual reproduction where a new organism grows from the parent

Cnidaria

"cup shaped" animals with tentacles and stinging cells

Radial symmetry

body parts arranged around a central point

Cnidocysts

stinging cells used for defense and capturing prey

Gastrovascular cavity

primitive stomach where digestion occurs

Medusa

body form with tentacles pointing down

Jellyfish

example of a medusa cnidarian

Polyp

body form with tentacles pointing up

Hydra

example of a polyp cnidarian

Coral

example of a polyp cnidarian

Sea anemone

example of a polyp cnidarian

Platyhelminthes

flatworms

Bilateral symmetry

body can be divided into equal left and right halves

Tapeworm

parasitic flatworm with no digestive system

Scolex

hook like head of a tapeworm

Proglottid

body segment containing egg and sperm cells

Planarian

free swimming flatworm with a simple digestive system

Fluke

parasitic flatworm with a complex life cycle

Nematodes

roundworms

Complete digestive system

digestive tract with 2 openings

Ascaris

hookworm example

Trichinella

porkworm example

Rotifers

free living roundworms

Annelids

segmented worms

Closed circulatory system

circulatory system with hearts and blood vessels

Cerebral ganglion

simple brain or nerve center

Complex digestive system

system with stomach, gizzard, and intestine

Earthworm

example of an annelid

Leech

example of an annelid

Echinoderms

spiny skinned marine animals

Echino

spiny

Derm

skin

Starfish

example of an echinoderm

Sea urchin

example of an echinoderm

Sand dollar

example of an echinoderm

Water vascular system

system used for movement and feeding in echinoderms

Tube feet

tiny water filled projections used for movement

Mollusks

soft bodied animals usually covered by a mantle

Mollusk Latin meaning

soft body

Radula

scraping mouth part used for feeding

Mantle

membrane that produces the shell

Open circulatory system

system with no blood vessels

Gastropods

stomach foot mollusks

Bivalves

mollusks with 2 shells

Cephalopods

head foot mollusks

Cephalopods characteristics

have seeing eyes and a brain

Arthropods

animals with more species than all other animals combined

Arthro

Greek word meaning joint

Pod

word meaning foot

Jointed appendages

limbs with joints

Exoskeleton

hard outer covering

Molting

shedding of the exoskeleton resulting in growth

Segmented body

body divided into sections

Head

front body section containing most sense organs and mouth

Thorax

middle body section where legs and wings are attached

Abdomen

hind body section containing most internal organs

Compound eyes

eyes with multiple lenses

Spiracles

holes in the exoskeleton used for breathing

Tracheae

tubes through which oxygen is exchanged in the abdomen

Book lungs

spider lungs

Horseshoe crab

first land animal arthropod

Myriapods

group including centipedes and pill bugs

Centipede

example of a myriapod

Pill bug

example of a myriapod

Crustaceans

arthropods that mostly live in water

Crustaceans characteristics

have claws and taste buds on antennae

Decapods

crustaceans with 10 legs

Lobster

example of a decapod

Crab

example of a decapod

Shrimp

example of a decapod

Barnacles

type of crustacean

Copepods

zooplankton crustaceans

Arachnids

arthropods with 2 body segments and 8 legs

Cephalothorax

head and thorax fused into one segment

Spinnerets

structures that produce silk

Scorpion

example of an arachnid

Ticks and mites

examples of arachnids

Spiders

example of arachnids

Insects

arthropods with 3 body segments and 6 legs

Incomplete metamorphosis

life cycle of egg, nymph, adult

Nymph

stage in incomplete metamorphosis

Grasshopper

example of incomplete metamorphosis

Dragonfly

example of incomplete metamorphosis

Complete metamorphosis

life cycle of egg, larva, pupa, adult

Larva

stage such as caterpillar, maggot, or grubworm

Caterpillar

example of a larva

Maggot

example of a larva

Grubworm

example of a larva

Pupa

stage between larva and adult

Butterfly

example of complete metamorphosis

Honeybee

example of complete metamorphosis

Housefly

example of complete metamorphosis

Social insects

insects that live in colonies with castes

Workers

female social insects