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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
We
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.