CHAPTER 12 INTRO TO ANIMALS (p. 330) There are over one million species and nine phylums.

ANIMAL CHARACTERISTICS 1)cannot make their own food (must eat other organisms).

2) must digest their food. - food must be broken down for the body to use.

3)Must move from place to place. -find food, escape predators, migrate, find mates, etc. - called locomotion.

4)must be multicellular. - many types of different cells.

5)eukaryotic - must have a nucleus. 6) does not have cell walls.

Vertebrates -animals which have a backbone. - provides support.

The backbone also protects the spinal cord. - nerves which connect the body to the brain.

Invertebrates -animals without a backbone. -97% of all animals are invertebrates.

Some invertebrates have a hard shell for protection and support. Ex. clam Some have a hard outer skeleton for support. Ex. grasshopper

Symmetry (P. 335) - the balanced arrangement of body parts around a center point or line. Radial Symmetry -arranged in a circle. Ex. jellyfish coral

Bilateral Symmetry -it can be divided into two equal halves. -each side is the same All vertebrates and most invertebrates are bilateral.

Dorsal - upper side Ventral - bottom side

Anterior - front end Posterior - hind end

Asymmetry -no way to divide the animal into halves Ex. sponges

ASSIGNMENT: READ PP

SIMPLE INVERTEBRATES (p. 346) Phylum Porifera Sponges -‘pore-bearing’ -found mostly on the bottom of shallow waters. - mostly salt water. - cannot move - sessile.

Not a real sponge…

-has pores -water enters and the sponge filters out unicellular organisms. -expels water thru a different pore - osculum -are called filter feeders

-oxygen is absorbed the same way. -The simplest of animals. -two layers of cells. -no organs or tissues. Some once thought that sponges were plants.

How my brother scratched my Dad’s 1960 Buick Electra Spicules -used for support. - a simple skeleton.

Collar cells - pull water and food into the sponge.

ASSIGNMENT WORKSHEET: “What is an Animal?”

Asexual Reproduction in Sponges Regeneration - small parts break off and can grow into a ‘new’ sponge.

Asexual Reproduction in Sponges Gemmules -are a hard outer covering with sponge cells inside. -created during harsh periods. - no food, low water levels.

-when conditions improve, the gemmule breaks open and a ‘new’ sponge forms. (freshwater only - ocean conditions rarely change).

Sexual Reproduction in Sponges -some species have separate sexes but most are hermaphrodites. - both male and female.

- Sperm and eggs are released into the water where fertilization occurs. -it develops into a larva (young sponge) which has cilia to swim and find a spot to attach -- then it grows into a sponge.

ASSIGNMENT WORKSHEET “SIMPLE ANIMALS”

Phylum Cnidaria “stinging cells” (p. 339) Ex. jellyfish, coral, sea anemones. -once called Phylum Coelenterata - “hollow body” -more complex than sponges - but still simple. - no tissues or organs.

-all have radial symmetry. -most have arm-like tentacles. -the tentacles have stinging cells called nematocysts.

CORAL NEMATOCYSTS

-the prey bumps into the nematocyst and is stunned. -the tentacles pull the prey into the mouth.

Can be dangerous to people. Ex. Portuguese man-o-war

Portuguese Man-o-war

CORAL -have a hard outer skeleton. - when it dies, a new coral grows over the dead one building a reef.

Cnidarians are the first animal to have a simple nervous system. -called a nerve net. - carries impulses and connects all parts of the organism,

Cnidarians can have two body plans. (p. 339) 1)medusa - free-floating and often umbrella shaped. Ex. jellyfish

2) Polyp -attached to a hard surface. -often tube shaped. Ex. sea anemone, coral

Polyp Medusa Some species can alternate between body plans.

ASSIGNMENT: WORKSHEET “Stinging Cells”

Phylum Platyhelminthes “Flatworms” -flat bodies. -bilateral symmetry. -simple animals - but more complex than cnidarians. - absorb oxygen thru their skin.

- most are parasites - but some are free-living. Ex. planaria (p. 345) -free-living -has an eyespot. - can sense changes in light.

A planaria can regenerate body parts. - it has a simple nervous system in the shape of a ladder.

A tapeworm is another example of a flatworm. (p. 346) -are parasites. - can enter the body by eating grass or uncooked meat which holds the tapeworm eggs.

Tapeworms have hooks and sucker to attach to the intestine. -it absorbs the host’s digested food. - its ‘head’ is called a scolex.

Each section is called a proglottid - and is full of eggs as it matures.

ASSIGNMENT: QUESTIONS P P P

Phylum Nematoda “Roundworms” -largest worm phylum. -more complex than flatworms. - has a continuous digestive tract.

“tube within a tube” mouth anus - excrete waste

- some are parasites Ex. hookworm - it enters thru the skin - its larvae are very small. - it travels the blood system into the lungs.

-A cough brings it up into the mouth -it is swallowed into the digestive system. - feeds on blood.

Ex. Heartworm

Ex. Trichinella worms -causes trichinosis - from eating uncooked pork.

Another parasite is ascaris

ASSIGNMENT: WORKSHEET “SIMPLE CREATURES’

Phylum Annelidia “Segmented worms” “little rings” (p. 365) Ex. earthworm, leech -most advanced of the worms. - has a body cavity that holds organs.

Earthworm Anatomy (p. 366) setae - tiny hairs on each segment. - for movement - to ‘hold on’ to the soil. Clittelum -thick band - used for reproduction.

mouth DIGESTIVE SYSTEM - they ‘eat’ soil. cropgizzard intestine anus

Crop - storage area. Gizzard - grinds the soil/organics. Intestine - breaks down food/absorbs nutrients. crop gizzard intestine

Earthworms have a closed circulatory system. -the blood is contained in vessels. It has five ‘hearts’ called aortic arches to pump blood.

- absorb oxygen thru their skin. - has a nervous system with a brain and a main nerve cord. ventral nerve cord intestine

- are hermaphrodites. - have both male and female parts. - but must receive sperm from another worm. - it cannot fertilize itself.

ASSIGNMENT: WORKSHEET “ANNELID ANATOMY”

Leeches -are a parasitic segmented worm. -produce an anesthetic. - the host cannot feel the bite.

A LEECH “MOUTH”

- were once used to ‘bleed’ people with illnesses. - used today to keep blood flowing to reattached body parts.

-Leeches have an anticoagulant in their saliva. -stops blood from clotting.

ASSIGNMENT: WORKSHEET ‘CHAPTER REVIEW’