Classifying AnimalsVertebrates and Invertebrates

Mrs. Christman

Objective

Explore how to classify animals. Understand that animal cells are organized

into tissues, organs, and systems. Describe observable characteristics of

vertebrates and invertebrates. Classify animals by using a key.

Main Idea

While all animals’ cells have similar basic structures, the specific structure and function of these cells are very diverse. The more cells, tissues, organs, and systems that organisms have in common or that are similar, the more closely related they are.

Vocabulary

tissue-similar cells that have the same job or function

organ- a group of tissues that work together, like a heart or brain.

system- a group of organs that work together to do a certain job. For example, a mouth, stomach, and intestines make up the digestive system of an animal.

Classifying Animals

Scientists classify animals based on cell structure, how cells are organized into tissues, how tissues are organized into organs, and how organs are organized into systems.

Classifying Animals Scientists look at the similarity of certain traits to

classify animals. For example, at first glance a bat and an eagle

may seem more alike than a bat and a cat. However, a bat and an eagle are very different.

The bat and cat are both mammals. Both have hair and both feed their young mother’s milk.

Birds on the other hand, are not mammals. Birds do not have fur and do not fee their young mother’s milk.

Vertebrates and Invertebrates

Animals are divided into two large groups. One group is made up of animals that have

backbones (vertebrates) The second group are animals that do not

have a backbone. They are called invertebrates.

Sponges

One of the simplest kinds of animals is a sponge.

Belong to a group called Porifera. Have tissues but no organs. No stomach,

mouth, or other organs Body is covered with pores (holes) Most live in oceans

Invertebrates with Stinging Cells Belong to Cnidaria group They have tentacles-long

threadlike structures that make poisons.

They have a mouth They live on the ocean floor

jellyfish

Sea anemone

coral

Flatworms Belong to a group Platyhelminthes Have flat bodies Have heads and tails Most flatworms do not have true organ

systems

Flatworm

Roundworms

Belong to a group Nematoda Have heads and tails Unlike flatworms,

roundworms have round bodies, a digestive systems, and a simple nervous system.

Live all over earth, inside plants, and animals

Roundworms

Earth Worms

Belong to a group called segmented, or Annelida

Have heads and tails. Many segmented worms have eyes and other specialized organs, such as jaws or gills

Have circulatory, digestive, and nervous systems

They can grow back parts if they lose parts. An earthworm has hairs on it to help it go

through the dirt

Segmented

Invertebrates with Soft Bodies

Snails, clams, and octopuses belong to the mollusks group

Most have a shell either inside or outside their body. They make their shells from minerals in the water.

Have three main body parts, a kind of foot, a tissue covering called a mantel, and a compartment holding internal organs.

squid

snail

octopus

Invertebrates with Soft Bodies

They live on land and fresh water and ocean water.

They have gills for breathing. They have jaws or other organs

for capturing food. Have a circulatory system.

More complex mollusks, like octopuses, have a well-developed brain.

squid

snail

octopus

Invertebrates with Spiny Skins Unlike arthropods, the

Echinodermata, or echinoderms, have a skeleton inside their bodies

They have bodies with at least 5 sections

They have suction cup feet to walk They use tubes to catch food to.

ArthropodsThere are 4 groups

C ru s tace a ns A ra ch n ids In se c ts C e ntip ed esM illip e d es

A rtho po ds

There are more arthropods on Earth than any other kind of animal.

Arthopods

They have keen sense organs They have exoskeletons, a tough

outer skeleton. They have jointed legs, and a body

made up of two, three, or more sections.

Crustaceans

They have five pairs of legs

They live near or on the ocean floor

Live on land and water

They have antennae

Arachnids

Spiders mites and ticks.

4 pairs of legs Most live on land. Some live in fresh

water They are called

parasites.

Insects

Largest group of arthropods

3 pairs of legs 3 main body part

sections 2 pairs of eyes Have mouths

Millipedes & Centipedes

Many body segments Live under rocks & dark

places Really have less than 100

legs Protects itself by curling up Millipedes have 4 legs on

each segment Centipedes have 2 legs on

each segment

millipede

centipede