1. Invertebrates

2. Animal Characteristics
Animals are the most physically diverse kingdom of organisms.
They range in size from twice the length of a school bus to microscopic

3. 4 Major Characteristics of Animals
1. They are multi-cellular heterotrophs
2. Animal cells are supported by collagen
three-stranded protein
found in bone, skin, ligaments, fingernails, and hair

4. 3. Animals are diploid and reproduce sexually
Diploid cells have two copies of each chromosome: one copy from the mother and one from the father

5. 4. Animals have Hox genes Homeotic genes control early development.
Hox genes determine the position of cells differentiation.
A Hox gene mutation leads to the development of a body structure in the wrong position and/or animal diversity

6. Animal Diversity
Animals are grouped into vertebrates (animal with backbones) or invertebrates (animals without backbones)
More than 95% of all animal species are invertebrates- an animal without a backbone

7. Animals are grouped according to these 3 criteria
gastrovascular cavity
mouth
mesoglea
oral arms
tentacles
1. Body Plan
2. Tissue Layers
3. Developmental Patterns
blood vessels
brain
hearts
muscle
segment
nerve cord
mouth
digestive track

8. There are two types of Body Plans
Bilateral Symmetry
Radial Symmetry
Body divides equally along one plane
Body arranged in a circle around a central axis

9. Tissue Layers Bilateral Radial
Have 3 distinct layers: ectoderm, endoderm, and mesoderm
Ecto- develops into skin, the brain, and nervous system
Endo- lines the “gut”
Meso- develops into internal organs
Have two distinct layers: ectoderm and endoderm

10. Animals are separated into two major groups
Protostome- mouth develops before anus
Deuterostome- anus develops before mouth

11. Invertebrate Diversity

12. Sponges Sponges are the most primitive animals on Earth.
Sponges share common characteristics.
Sessile- attached to floor of ocean (do not move)
reproduce both sexually and asexually
filter feeders- strain food particles from water

13. Sponges have three types of cells
Pinacocytes- form the sponges outer layer
Choanocytes- pull water into sponge and help trap food
Ameobocytes- absorb and digest food particles
osculum
choanocyte
amoebocyte
pinacocyte
pore
spicule

14. Sponge Video

15. Cnidarians (Jellyfish)
Cnidarians come in two body forms
Polyp- cylindrical tubes with mouth and tentacles facing upward
Medusa- umbrella-shaped, with mouth and tentacles on the underside

16. Cnidarian Video

18. Cnidarian Anatomy
Cnidarians are made up of two tissue layers separated by mesoglea
The outer tissue layer has three cell types.
contracting cells – covers the surface of the cnidarian
nerve cells- sends information around animal to coordinate movement
cnidocytes (which contain nematocysts)- “stinging cells” used for defense and capturing of prey
barbs
coiled
nematocyst
discharged

19. Flatworms have a solid body and incomplete or absent gut.
They have no circulatory system
head
pharynx
mouth
sucker
eyespot
reproductive
system
gut cavity

20. 3 classes of Flatworms Planarians- free-living non parasites
Flukes – parasites which can infect humans and cause serious disease (schistosomiasis)
Infects 200 million people in Africa and Southeast Asia
Contracted by wading in or drinking contaminated water
Tapeworms- are parasites that live in vertebrates gut
Use suckers or hooks to attach to host
Absorb nutrients from the food the host eats

22. Tapeworm Video

23. Mollusks
Mollusks have a complete digestive tract with two openings – a mouth and an anus
Coelom ( fluid filled body cavity)is present
Except in flatworms
Mollusks have all three tissue layers
Have a brain and spinal cord (cephalization)
Have a circulatory system
Primitive species (open) such as bivalves
Advanced species (closed) such as octopus and squid

24. Mollusks Anatomy Mollusks share at least one of three features.
radula : file like teeth used to obtain food
mantle : area of tissue covering the internal organs, sometime secrete a hard outer shell for protection
ctenidia: flat gills found in the mantle
intestine
stomach
digestive gland
foot
anus
salivary gland
crop
mouth
radula
mantle
mantle cavity
heart

25. Most mollusks are classified into three classes.
Gastropods: includes snails, abalone, and slugs they are found on both land and water
Bivalves (Pelecypods): clams, oysters, mussels, and scallops. Protected by two hinged shells
Cephalopods: squid, octopus, nautiluses, and cuttlefish. Most advanced mollusks and are predators

27. Mollusk Video #1

28. Mollusk Video

29. Annelids Three groups of Annelids
earthworms, leeches, and marine worms
They are characterized by having segmentation: division of the organism into repeated sections
They have a coelom and all three tissue layers
They breathe by diffusing oxygen through their skin
They are hermaphroditic so they can reproduce either sexually or asexually

30. Annelid Video

32. Roundworms
Roundworms have bilateral symmetry and shed their outer skeleton to grow.
Roundworms are protostomes with bilateral symmetry
brain
cuticle
pharynx
intestine
anus
tail

33. Roundworms have a psuedocoelom (“false” not complete body cavity)
They do not have a respiratory or circulatory system