Documents: Cnidaria and Body Essay

Submitted By lizette13sal
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Chapter 7. Simple Animals.

7.1 Animal Classification
1.5 million different kinds of living things - 1 million are animals.

Traits of Animals.
What makes animals different?
Consumers - cant make their own food - take in from surroundings - plants, animals, both
Most can move - helps them find food, if they don’t have developed other ways to get food
Multicellular organisms. cells organized into tissues, organs, systems - muscles and igestive systems
All animals belong to one of two groups - vertebrates or invertebrates
Vertebrates- animals with backbones - humans,

Invertebrates - Animals without backbones
Most animals have symmetry: the balanced arrangement of body parts around center point. Radial Symmetry - Arranged in a circle around a center point. Bilateral symmetry - body can be divided lengthwise into two equal sides.
How animals are classified
5 kingdoms
•Kingdom, Phylum, Class, Order, Family, Genus, Species

9 phylums - sponges, stinging cell animals, 3 worm phyla, soft-bodied, jointed leg animals, Chordates

7.2 Sponges and Stinging-cell Animals simplest invertebrates

SPONGES- simple invertebrates that have Pores: a small opening
-Don’t have definitive shape - Trees or vases?
Are many colors do not move freely on their own - attach to rocks in shallow oceans
Some in fresh water
Pores provide canals through the sponge where water flows through
Small organsisms in water are food for sponges which flows through pores and trapped by food getting cells
Two cell layers thick
No muscles or nerve cells, tissues or organs
3 kids of cells
Food getting - beats flagellum to move food through
Protection - cover sponge
Makes chemicals/reproduction/carries food - makes a chemical which forms the skeleton
Reproduce sexually and asexually - sponges produce bothsperm and eggs
Sexual Reproduction = 2 sponges
Asexual = Small pieces of a sponge’s body break off and form separate, new sponge.
Natural sponges are used for household purposes because after they die their ibers remain and can hold water and their elastic bodies all ow them to be squeezed and return to normal.

STINGING CELL ANIMALS: animals with stinging cells and hollow, savlike odies that lack organs. most live in oceans = few in fresh water lakes and streams
Hydras, colas, sea fans, jellyfish, sea anemones armlike parts called tentacles that surround the mouth
Corals and sea fans have chemicals that harden the outside of their bodies to protect them - made of man small animals
Have radial symmetry and saclike bodies made of two cell layers have mouth - only opening in and out of body many fasten themselves to the bottom on rocks like a suction cup tentacles have thousands of stinging cells with hairlike triggers- a stinging dart containing poison soots into the water stunning the animal - pushes the animal through its mouth where it is digested - undigested food leaves through the mouth

Jelly fish very painful to humans
Have muscle cells and nerve cells used to move tentacles - jellyfish use muscles to swim
Reproduce sexually by forming eggs and sperm - released into the water
Some can reproduce asexually by forming buds - hydra


Flatworms: simplest worms - flattened body, 3 layers of cells - thin, inner and outer- thicker , middle most are parasites - live on or in another thing and get food from them - cause them harm

Tapeworm: flattened ribbon like body divided into sections can live in the intestine of most vertebrates has suckers and hooks on one end to hold onto the intestine of its host
No mouth for organs to digest food - they absorb food that has already been digested.
1. pig eats tapeworm eggs on the ground and they hatch in the pigs intestine
2. young worms enter the pig’s bloodstream then travel to the muscles and burrow into them
3. young worms form cysts in the muscles
4. if a person eats raw or…