1. Introduction to Animals Invertebrate Evolution and Diversity
Chapter 25
Chapter 26.1

2. Introduction to Animals
Chapter 25

3. Characteristics of Animals
Kingdom – Animalia
Multicellular
Heterotrophic
Eukaryotic
Lack cell wall

4. Types of Animals Invertebrates Lack backbone or vertebral column
Sea stars, worms, jellyfish, insects

5. Chordates
Exhibit four characteristics during at least one stage of life
Dorsal, hollow nerve cord
Notochord
Tail that extends beyond anus
Pharyngeal pouches
Lancelet

6. Chordates with backbones = Vertebrates
Fishes, amphibians, reptiles, birds, mammals

7. What Animals Do to Survive
Maintain homeostasis by gathering and responding to information
Feedback inhibition

8. Obtain and distribute oxygen and nutrients
Collect and eliminate CO2 and waste
Reproduce

9. Animal Development Animals have a wide variety of forms.
The following developmental factors determine the body plan:
Levels of organization : cells, tissue, organ, organ systems
Arrangement of Germ layers:
differentiate into different tissue types:
Endoderm (inner): digestive tract
mesoderm (middle): muscles, blood
ectoderm (outer): skin, nervous system

10. Development, cont. Overall Patterns of Embryological Development
Protostomes
Blastopore becomes mouth
Most invertebrates
Deuterostomes
Blastopore becomes anus
Chordates, Echinoderms (sea stars)

11. Development, cont. Body Cavity Formation
Coelom – completely lined with tissue derived from mesoderm
Acoelom – lack a body cavity
Pseudocoelom – partially lined with mesoderm

12. Development, cont. Body symmetry: Radial
body parts extend from a central point
Divides into equal halves
Bilateral
Right and left sides are mirror images of each other
Distinct anterior and posterior ends and dorsal and ventral sides

14. Segmentation Cephalization Limb Formation Repeating Parts
Worms, insects, vertebrates
Cephalization
concentration of sense organs and nerve cells at anterior end (head)
Limb Formation
Legs, Flippers, Wings

16. Cladogram of Animals Phyla defined by: Ex. Phylum Arthropoda
Adult body plans
Patterns of embryological development
Ex. Phylum Arthropoda
Body plan bilateral symmetry
Segmentation
Cephalization
External skeleton
Jointed legs

18. Invertebrate Evolution and Diversity
Cladogram of invertebrates determined by
evolutionary relationships among major groups
sequence of evolution of important features

19. Sponges Phylum: Porifera (“pore bearers”)
Most ancient member of kingdom Animalia
Multicellular, heterotrophic, lack cell walls, contain few specialized cells
Clade Metazoa

20. Cnidarians jellyfishes, sea fans, sea anemones, hydras, corals
Aquatic, soft-bodied, carnivorous, radially symmetrical, stinging tentacles around mouths
Simplest animals with body symmetry and specialized tissues

21. Nematoda (Roundworms)
Unsegmented worms
Pseudocoeloms
Specialized tissues and organs
Digestive tract with two openings

22. Platyhelminthes
Flatworms
Soft
Unsegmented
Have tissues and internal organ systems
Bilateral symmetry
Cephalization
Do not have coeloms

23. Annelids earthworms, some marine worms, leeches Segmented bodies
True coelom lined with tissue derived from mesoderm

24. Arthropods
Phylum: Arthropoda – spiders, centipedes, insects, crustaceans
Bodies divided into segments
Exoskeleton
Cephalization
Jointed appendages

25. Mollusks Phylum: Mollusca – snails, slugs, clams, squids, octopi
Soft-bodied
Internal or external shell
True coeloms surrounded by mesoderm and complex organ systems
Free-swimming larva

26. Echinoderms
Phylum: Echinodermata – sea stars, sea urchins, sand dollars
Spiny skin
Internal skeleton
Water vascular system – used for walking and gripping prey
Five-part radial symmetry

29. Animals
Chordates
Invertebrates
Cnidaria
Hexacorallia
R. daphneae
Other invert.
Other Cnidaria
Other Hexacorallia
Order:
Class:
Phylum:
Sub-kingdom:
Kingdom: