1. Introduction to Animals
Unit 12
Intro to Dissection

2. Which one of these is an animal?

3. What makes an animal?
Basic Characteristics

4. Intro to Animals Basic Characteristics: Heterotrophic Eukaryotic
Multi-cellular
Lack cell walls

5. Survival of Animals Maintain homeostasis
Have a way of movement and support
Gather and respond to information
Obtain and distribute oxygen and nutrients
Collect and eliminate CO2 and other wastes
Reproduce

6. Animal Bodies
Animals are classified based upon their body plans and patterns of embryological development

7. Features of a body plan Major features Body plan:
Unique organization of particular body structures and how they perform life’s essential functions
Major features
Levels of organization
Body symmetry
Germ layers
Body cavity
Embryological development
Segmentation
Cephalization

8. In your notebooks
Make a table that will help explain evolutionary relationships among animal phylum
Major phylum vs. the major body plans features
Sponges
Cnidarians
Flatworms
Roundworms
Annelids
Mollusks
Arthropods
Echinoderms
Chordates

9. Level of Organization Specialized Cells Tissues Organs Organ systems
Sponges are the ONLY animal that contain one level of organization
specialized cells
Cnidarians have only have two

10. Body Symmetry Asymmetry (sponges, corals)
No pattern
Radial symmetry (starfish, cnidarians)
Have multiple planes that can go through the center of the body
Bilateral symmetry (flatworms, arthropods, chordates)
Have only a single plane that divides the body equally into left & right sides

11. You try.....

12. Germ Layers Cells develop into 3 germ layers Ectoderm (outer)
forms skin, nerves, sense organs
Endoderm (inner)
forms liver and lungs
Linings of the digestive and respiratory systems
Mesoderm (middle)
forms muscles & circulatory, reproductive, and excretory systems
NOT present in sponges
Cnidarians only 2

14. Body Cavity Body cavity Acoelomate Pseduocoelomate True Coelomate
a fluid-filled space between the digestive tract and body wall
Acoelomate
Pseduocoelomate
True Coelomate

15. Coelomates Internal body cavity fully lined with mesoderm
Body organs suspended in this cavity
Complex animals

16. Acoelomates Sponges, Cnidarians and flatworms Lack a body cavity
Solid body filled with cells

17. Pseudocoelomates
Roundworms have a functional body cavity NOT fully lined with mesoderm
Notice around the digestive tract wall

18. Embryological Development
All life begins as a zygote and develops into a blastula (hollow ball of cells)
Pinches in (like a finger in a balloon) and opening called blastopore
Protostome
Blastopore becomes the mouth
Deuterostome
Blastopore becomes the anus
Echinoderms and Chordates

21. Segmentation
Occurs whenever animal bodies are divided into repeating units or segments
Found in more complex animals
Earthworms show external segmentation
Humans show internal segmentation (backbone)

22. Cephalization
The concentration of sense organs and nerve cells at their anterior ends
Known as the “head”
Found in bilateral symmetrical animals
Not present in sponges,
Cnidarians, and Echinoderms

23. `

24. Differences between animals
Invertebrates- animals that do not have a backbone
About 95% of animals
Contain 33 different phylum
Vertebrates- animals that contain a backbone
About 5% of animals
Contain phylum Chordates

25. 4 main characteristics Notochord Pharyngeal Pouches
Long supporting rod that runs through the body, most only have when they are embryos
Pharyngeal Pouches
Paired structures in the throat
May develop into gills
Pharynx in humans
A tail that extends beyond anus
Nerve cord

26. Animal Systems
How do the structures of animals allow them to obtain essential materials and eliminate wastes?
Systems:
Feeding and digestion
Respiration
Circulation
Excretion

27. Feeding and Digestion Obtaining food: Herbivore = eats plants
Carnivore = eats animals
Omnivore = eats plants and animals
Detritivore = feed on decaying organic material
Filter Feeders = aquatic animals that strain food from water
Parasite = lives in or on another organism (symbiotic relationship)

28. Feeding and Digestion Processing Food: Intracellular Digestion
Sponges and Cnidarians
Passes nutrients through cells by diffusion
Extracellular Digestion
Process where food is broken down in digestive system
Humans, etc.

29. Feeding and Digestion

30. Respiration Take in oxygen and let out CO2
Terrestrial Animals
Aquatic Animals
All use lungs
Some have “special” features:
Book Lungs (spiders)
Tracheal tubes (insects)
Skin (earthworm)
Air sacs (birds)
Gills
Feathery structures that actively pump water over them

31. Respiration

32. Circulation
Most animals move blood through their bodies by using one or more heart or hair-like structures
Two major circulatory systems:
Open (Arthropods and most mollusks)
Blood is only partially contained in blood vessels
Closed
Completely contained in blood vessels

33. Circulation

34. Excretion elimination of metabolic wastes, such as ammonia
Terrestrial Animals
Aquatic Animals
Invertebrates
Annelids and mollusk produce urine in nephridia that leaves through pores
Insects have malpighian tubes that absorb uric acid and combine it with digestive wastes
Vertebrates
Kidneys
White paste in birds and reptiles
All ammonia to diffuse out of their bodies into water
In some cases, diffusion across the gill membrane

35. Response: Invertebrates
Nervous System
Nerve nets (cnidarians)
Nerve cords (echinoderms)
Ganglia (mollusks, arthropod, flatworm)
Sensory organs
Compound eyes
Simple eye- detect movement
Eyespot – detect light

36. Movement & Support Skeletons Hydrostatic (cnidarians and annelids)
Fluids held inside, changes body shape
Exoskeleton (arthropods and mollusks)
Hard body covering made of chitin or shell made of calcium carbonate
Molting
Endoskeleton (echinoderms and chordates)

37. Reproduction Asexual vs. sexual (more to come later)
Internal vs. External Fertilization (again more to come later)