CHAPTER 7

Animal classification Key science words

vertebrateinvertebratesymmetry

TRAITS OF ANIMALS

Animals are consumers Must take in food from their

surroundings Some animals eat plants, others eat

other animals Animals digest and store food in their

bodies

Most animals can move from place to place

Animals are multicellular organisms Cells are grouped into tissues and

organs that form systems Most animals have a nervous,

digestive, and reproductive system

TWO GROUPS OF ANIMALS

Vertebratesanimals with backbones

fish, amphibians, reptiles, birds

Invertebrates animals without a backbone worms, and insects

SYMMETRY

BALANCED ARRAINGEMENT OF BODY PARTS AROUND A CENTER POINT OR ALONG A CENTER LINE

Two types of symmetry Radial Bilateral

SYMMETRY

Radial Body parts are arranged in a circle

around a central point Ex. A sea anemone fig 7-1b

SYMMETRY

Bilateral The body can be divided lengthwise

into two equal sides, a right side and a left side

This includes all vertebrates and some invertebrates

The animal must have a head and a tail end, and an upper and lower half

REVIEW OF TRAITS

1. Animals can’t make food, they must catch it and eat it

2. Most animals can move from place to place

3. Animals have many cells 4. Most animals have some type

of symmetry

9 MAJOR GROUPSOF CLASSIFICATION

Sponges, stinging celled animals, 3 worm phyla, soft-bodied animals, jointed-leg animals, spiny skinned animals, chordates

Sponges are the smallest phyla, jointed- leg animals are the largest, refer to fig. 7-2

SPONGES AND STINGING-CELLED ANIMALS

Simple Invertebrates Have pores Do not move on their own Live in salt and fresh water Water comes in through the pores and

out through a hole at the top center of the body, food from the water gets trapped by food getting cells inside the body

SPONGES CONT.

Two cell layers thick Have no muscles or nerve cells No tissues, organs, or organ

systems Reproduce sexually or asexually, by

egg and sperm, or by budding Sponges are asymmetrical lacking

symmetry

STINGING-CELLED ANIMALS

Animals with stinging cells Hollow sac-like bodies Lack organs Live in the ocean and in fresh

water Examples: jellyfish, coral, sea fan

Stinging-celled cont.

Have arm-like parts call tentacles that surround the mouth

Have RADIAL symmetry A body cavity contains an opening

called the mouth It’s the only way into and out of

the body

Stinging-celled cont

Attach themselves to the ocean bottom with or to rocks with a structure called a disc

Do not move from place to place How do they catch their food? With their tentacles

WORMS

Worms are invertebrates 3 phyla---flatworms, roundworms,

segmented worms

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Tentacles contain poison darts that stuns the animal that touches them

Food enters through the mouth and undigested food leaves through the mouth

Reproduce sexually and asexually

FLATWORMS

Simplest worms Flat body, 3 layers of cells, outer,

middle, and a thick middle layer Most flatworms are parasites Parasites live in or on other living

things getting food from them (called the host)

TAPEWORM

Flat ribbon-like body divided into sections

Live in the intestine of almost any kind of vertebrate

Have suckers and hooks that hold onto the sides of the intestine

They absorb food that has already been digested

TAPEWORM CONT.

Tapeworms in humans are not as common as in other countries

In the us waste is treated with chemicals at sewage plants

Meat is inspected for cysts However always cook your meat

well Copy down the life-cycle of a

tapeworm into your notes pg 143

ROUNDWORMS

Have long bodies with pointed ends 3 layers of cells Some cannot be seen without a

microscope Many are parasites Hosts are people, dogs, cats, plants

ROUNDWORMS CONT

Found in the soil Hookworms are parasites of

people, they enter through the skin of the feet, once inside they move to the intestine, and feed on the hosts blood

Refer to figure 7-11

ROUNDWORMS CONT

Have long rounded bodies Has a mouth and an anus (first

animal to have a 2 way gut) First animal to have an intestine Males and females are separate

animals, first animal to have separate sexes

SEGMENTED WORMS

Bodies divided into sections called segments

3 cell layers Most complex of the worms Live in salt water, fresh water and

on land Ex: leech, earthworm

SEGMENTED WORMS CONT

Segments have muscles Have a mouth and an anus Has an intestine Two blood vessels 5 pairs of simple hearts that carry

oxygen and food to all the cells Has nerves and a simple brain Separate sexes

SOFT-BODIES ANIMALS

Soft body protected by a hard shell Body covered by a thin fleshy

tissue called a mantle (mantle makes the shell)

Have a muscular foot for moving Have a head with a mouth with

teeth

1st CLASS OF SOFT-BODIED ANIMALS

Snails and slugs Live on land and in the water Glide using a muscular foot snails(shell) slugs(no shell) Snail has two tentacles (sense

organs) Contain eyes that detect light

2nd class

Clams, oysters, scallops Have two shells that fit together Have a muscular foot Live buried in the sand and filter

water to get food

3rd class

Octopus, squid, cuttlefish Squid, cuttlefish have shells inside

their bodies Octopus has no shell Have tentacles surrounding the head Well developed eyes Rapid swimmers

Features of soft-bodied animals review

1 all are invertebrates 2 soft body covered by a mantle 3 most have 1 or 2 external shells,

or an internal shell 4 most have a foot by which they

move about

will consider the 9 phyla shown below.