1. Invertebrates
Comparative Anatomy

2. I. Comparison by Cavity Type
A. COELOM – LIQUID FILLED BODY CAVITY B. COELOMATES – ORGANISMS WITH A BODY CAVITY

3. II. CLASSIFICATION OF COELOMATES
A. CLASSIFICATION BY CAVITY STRUCTURE B. CLASSIFICATION BY EARLY DEVELOPMENT C. CLASSIFICATION BY CLEAVAGE TYPE

4. III. CLASSIFICATION BY. CAVITY. STRUCTURE A. ACOELOMATE 1
III. CLASSIFICATION BY CAVITY STRUCTURE A. ACOELOMATE Prefix “A-” “without” Organism having a cavity without a lining

5. PSEUDOCOELOMATE
1. Prefix “PSEUDO-” “FALSE”
2. Organism having an incompletely lined cavity

6. C. EUCOELOMATE
1. Prefix “EU-” “TRUE”
2. Organism having a true cavity that is completely lined
Eucoelomate (Earthworm)

7. IV.CLASSSIFICATION BY EARLY DEVELOPMENT
A. BLASTULA – hollow ball of cells B. BLASTOPORE - opening formed by the folding of the blastula
Early evolutionary branches are formed based on events in development of bilateral symmetry.
Divisions include acoelomates, pseudcoelomates, and coelomates based on the structure of the body cavity.

8. 1. Formation of mouth from blastopore 2. Anus is secondary formation
PROTOSTOME
1. Formation of mouth from
blastopore
2. Anus is secondary formation
Early evolutionary branches are formed based on events in development of bilateral symmetry.
Divisions include acoelomates, pseudcoelomates, and coelomates based on the structure of the body cavity.

9. D. DEUTEROSTOME 1. Formation of anus from the. blastopore 2
D. DEUTEROSTOME Formation of anus from the blastopore Mouth is the secondary formation
Early evolutionary branches are formed based on events in development of bilateral symmetry.
Divisions include acoelomates, pseudcoelomates, and coelomates based on the structure of the body cavity.

10. V. CLASSIFICATION BY CLEAVAGE TYPE
CLEAVAGE- DIVISION OF
EARLY EMBRYONIC CELLS
B. EMBRYONIC CLEAVAGE
1. Determinate Cleavage
–creates high probability of unequal daughter cell survival
Division of this group is based not on a body cavity but events in early development.

11. 2. Indeterminate Cleavage
– division allows greater probability of equal daughter cell survival

12. 3. Holoblastic Cleavage
a. Def. -complete cleavage in embryos having a small yoke
b. Four Types
1) Bilateral
2) Radial - Deuterostomes
3) Rotational - mammals
4) Spiral – Protostomes (Annelids & Mollusks)

13. 4. Meroblastic Cleavage
a. Def.- incomplete cleavage in embryos having a large yoke
b. Two Types
1) Discoidal – fish, birds, reptiles
(yolk at one end)
2) Superficial - insects
(yolk in the center)

14. B. PROTOSTOMES – SPIRAL
CLEAVAGE
C. DEUTEROSTOMES – RADIAL

15. VI. Movement and Support
Three Types
* In most animals the muscles work together with some sort of skeletal system that provides firm support.
There are three main kinds of skeletal systems:
1) Hydrostatic skeletons – no hard structures such as bones or chitin plates
2) Exoskeletons – hard nonliving coating that encloses internal organs and muscles.
3) Endoskeletons – frameworks located in the body of animals.

16. 1. Hydroskeleton – lacking hard structures (bones)
Cnidarians
Flatworms
Roundworms
Earthworms
Mollusks

17. 2. Exoskeleton - hard nonliving. coating that encloses internal
2. Exoskeleton - hard nonliving coating that encloses internal organs and muscles.
Mollusks
Arthropods

18. 3. Endoskeleton – bony internal framework
Echinoderms Chordates

19. VII. Digestion Three Methods
A digestive system must accomplish several tasks
Ingestion of food
Mechanical breakdown of food particles
Chemical breakdown of food particles
Absorption of nutrients
Elimination of waste
Intracellular
All digestion occurs within individual cells of the animal
Incomplete extracellular
There is only one opening for absorption and elimination
Complete extracellular
There are two openings. A mouth for absorption and an anus for elimination.

20. 1. Intracellular - All digestion occurs within individual cells of the animal
Poriferans

21. 2. Incomplete Extracellular -Only one opening for absorption and elimination.
Cnidarians
Platyhelminthes

22. 3. Extracellular - Two openings:. A mouth for absorption and
3. Extracellular - Two openings: A mouth for absorption and an anus for elimination.
Cnidaria
Echinodermata
Arthropoda
Moullusca

23. VIII. Respiration All animals require Oxygen (O2).
Respiration also produces a byproduct CO2 that is toxic.
These two needs are accomplished by a process of gas exchange.
No respiratory system
Low energy needs,
Low metabolism, Uses little O2.
Small/flat/narrow
-No cell too far from surface
Moist skin
- Helps with diffusion
External respiratory system - Larger animals need O2 to enter in bulk
Gills are on outside of the body and are elaborate, folded structures that increase surface area.
As water passes over the gills, oxygen then diffuses into capillaries of a circulatory system.
The circulatory system transports O2 to cells where it is exchanged for CO2.
Internal respiratory system - Insects use a system of tubes called tracheae to get O2 close to cells. Most vertebrates use lungs to exchange gases.

24. A. No Respiratory System –. diffusion is used to get
A. No Respiratory System – diffusion is used to get oxygen through surface
Sponges,
Cnidaria,
Nematoda, &
Echinodermata

25. B. External Respiratory. System – diffusion through
B. External Respiratory System – diffusion through skin or special structures such as gills

26. C. Internal Respiratory System –Use lungs or tubular system (insects)

27. X. Internal Transport
Used to exchange gases with the respiratory system and body cells. It also transports those gases between the respiratory system and body cells.
No circulatory system - Animals that are small enough to diffuse gases in and out of the body also tend to use diffusion to transport those gases throughout the body.
Open circulatory system - A heart pumps blood into the body cavity where it moves past the organs and tissues. It is picked up by openings in the heart, which draws it up and then pumps it back out.
Closed circulatory system - The heart pumps blood through gills or lungs to exchange gases (except annelids). It uses arteries to pump away from the heart and veins to move it towards the heart. Capillaries are small blood vessels that are one blood cell in diameter where gas exchange with the body cells occurs.

28. A. No Circulatory System
Also Nematoda &
Echinodermata

29. B. Open Circulatory System – has no vessels

30. C. Closed Circulatory System – has vessels (veins/arteries)

31. IX. Environmental Response
A. Nerve nets
B. Cephalization – having a head; anterior centralizaton of sense organs
C. Central nervous system
Neuron – cell that carry messages for the nervous system
- Messages take the form of electrical signals called impulses.
- Receives and relays information about activities within the body.
- Monitors and responds to internal and external changes.

32. XI. Reproduction A. Asexual – one parent B. Sexual – two parents
All Living things reproduce.
Types of Reproduction
Asexual – only one parent
Budding – a small version of the animal grows off the parent. When it grows large enough it breaks off.
Fission – the adult splits in half. Each half then regenerates the rest of the body.
Parthenogenesis – an egg develops without the addition of sperm from a male.
Sexual – two parents, one supplies the sperm & the other supplies the egg.
Hermaphrodite – each parent is both male and female.
Male/Female – male supplies the sperm while female supplies the eggs.
External Fertilization – parents release both the egg and sperm into the environment. (Spawning)
Internal Fertilization – the male places the sperm inside the female’s body. Required, if reproduction is to occur on land.