1. An overview
Invertebrates

2. Response (1.Centralization)
A simple nerve net has concentrations of nerves at specific areas of the animal
This centralized format allows for quick movement of nervous signals to help coordinate response
Examples: jellyfish, flatworms

3. Response (2.Cephalization)
Animals with bilateral symmetry have concentrations of nerves at the anterior end of body
Cephalization increases as animals increase in complexity
Simple cephalization results in a ganglia or clump of nerves; more complex cephalization results in an organized brain

4. Response (3.Specialization)
The more complex the animals, the more highly specialized its sense organs!

5. Internal Transport Ways that materials are moved around the body
Oxygen & nutrients need to be brought to cells
Wastes need to be carried away

6. 1. Diffusion
Materials move directly through the tissues of the animals
Move from areas of high to low concentration
Examples: echinoderms (starfish) & flatworms

7. Closed System Network of blood vessels
Diffusion of materials occurs b/w blood & cells through blood vessels
Blood usually doesn’t directly contact tissues
Examples: annelids, chordates

8. Open System No blood vessels Tissues “bathed” in blood
Body sinuses collect blood
HEART pumps blood in BOTH open & closed systems!
Examples: arthropods & molluscs

9. Respiration
Goals are to supply oxygen and remove carbon dioxide from body cells
ALL systems require:
- system for increasing surface area for gas exchange
- need a moist gas exchange surface

10. Respiration across the skin via diffusion (ex. Hydra)

11. Gills exchange gases with surrounding water (ex. Crayfish)

12. Tracheal tubes (grasshopper) have evolved for breathing air

13. Reproduction & Development
Some reproduce ASEXUALLY by fragmentation or budding
Benefits:
- produce offspring quickly
- produce many offspring
Not so good stuff:
- genetically identical to parent (not good for diversity)

14. Most reproduce SEXUALLY
- new combinations of genes
- separate gametes (males produce sperm and females produce eggs)
- some are hermaphrodites (both genders at once)

15. External Fertilization
In less complex animals
Gametes are released into the surroundings (aquatic)
Large numbers of gametes at one time

16. Internal Fertilization
In more complex animals
Mostly land animals
Usually one egg fertilized, although many sperm released at one time
Sperm deposited directly in female reproductive tract

17. Movement Almost all animals use muscles for movement
These muscles work with a firm skeletal system that provides support
There are 3 types: exoskeleton, hydrostatic & endoskeleton

18. EXOSKELETON
Examples: molluscs & arthropods
Hard coating (made of chitin or calcium carbonate) covers internal organs

19. 2. HYDROSTATIC
Examples: cnidarians & flatworms
No hard structures (bone or chitin)
Muscles supported by water filled cavity

20. 3. ENDOSKELETON
Examples: echinoderms & vertebrates
Frame of support inside body
Muscles attach to skeletal structure

21. Feeding- Three Evolutionary Trends
1.How food is broken down
2.# of openings of digestive space
3.Specialized regions of digestive tract
Examples
Simple Animals
Intracellular digestion
Single opening
None  gastrovascular cavity digests & absorbs nutrients
Flatworms
Complex Animals
Extracellular digestion
Mouth takes in food  anus expels waste
Specialized regions as food moves in 1 direction through body
Molluscs & arthropods

22. Excretion
Regulates the levels of water in the body & get rid of nitrogenous waste
Formed during the process of cellular respiration

23. THREE types of wastes produced…
1.Ammonia (NH3)
2.Urea
3.Uric Acid
Relationship to environment
Highly toxic; very soluble in H2O
Soluble in H2O
Less soluble in H2O but not as toxic as ammonia
How they get rid of it
Diffuses through body tissues into surrounding water
Concentrated urea forms urine with excess H2O
Excreted as a thick paste
Animals that excrete this waste
Aquatic invertebrates
Terrestrial animals
Insects (terrestrial)

24. Flame cells in flatworms

25. Nephridia in earthworms

26. Malpighian tubules (grasshoppers)
Pre-urine is formed in the tubules
Wastes such as urea diffuse through walls
Ions such as sodium & potassium are moved actively
Water follows