1. Warm-Up, Monday
What is an animal?
What makes an organism an animal?

2. Animal Development
Chapter 18

3. What you need to know! The characteristics of animals.
The stages of animal development
The traits used to divide animals into groups
The four chordate characteristics.
Adaptations that lead to the development of mammals.

4. Animal Characteristics
Multicellular eukaryotes
Heterotrophic
Obtain nutrients by ingestion (eating)
Extracellular matrices hold the cells together
No cell walls
Nerve and muscle cells

5. Early Embryonic Stages
Meiosis makes haploid sperm and/or egg
Zygote: fertilized egg
Cleavage begins (division without growth)
Blastula: cells form an outer layer with a hollow inner cavity
Early Gastrula: in-folding of cells forms layers
Gastrula: complete layering of tissue

6. Early Embryonic Development

7. Animal Development Some animals develop directly into adults
Many animals develop into a larvae (sexually immature form) that has a different niche from the adult
Larvae undergo metamorphosis that transforms into an adult
Most animals are invertebrates

8. Invertebrates

9. Body Plan
Morphological and developmental traits that help to categorize animals
Tissues
Symmetry
Body Cavity
Protostomes or Deuterostomes

10. 1. Tissue
Tissue: Collections of specialized cells isolated by membranous layers
Ectoderm
Outermost layer that becomes the skin and nerve tissue
Mesoderm
Inner layer that becomes skeletal, muscle and blood tissue
Endoderm
Internal layer that becomes the digestive tissue

11. 2. Symmetry
Radial symmetry with tops and bottoms but no left/right/front/back
Bilateral symmetry with front (anterior), behind (posterior), backside (dorsal), and stomach (ventral)

12. Body Cavity (Coelom)
Fluid filled body cavity for organs, cushioning organs and/or to form a hydrostatic skeleton
Pseudocoelomate: body cavity lined w/ mesoderm and endoderm
True Coelom: organisms with a body cavity lined only with the mesoderm

13. 3. Protostome or Deuterostome
Protostome blastopore becomes mouth
Deuterostome blastopore becomes anus

14. Chordate Derived Characters

15. Phylum Chordata Characteristics
Dorsal (hollow) nerve cord
Notochord – long flexible rod that appears during embryonic development (not a spinal cord!)
Pharyngeal slits
Muscular post-anal tail

16. Chordates → Mammals

17. Tetrapods: https://www.youtube.com/watch?v=yvDQCa7rleI
Published on Feb 27, 2013
Professor Neil Shubin talks about the discovery of Tiktaalik and one of the greatest evolutionary events in Earth's history: when the very first fish ventured out onto land. Widely known as the "fishapod", Tiktaalik roseae is a 375 million year old fossil fish discovered by a team of six palaeontologists in the Canadian Arctic in Tiktaalik looks like a cross between the primitive fish it lived amongst and the first four-legged animals, a group called "tetrapods". Derived from "tetra-", meaning four, and "-pod", meaning foot, all animals that descended from these pioneer amphibians, including us, can be called tetrapods. Tiktaalik lived about 12 million years before the first tetrapods (which are approximately 363 million years old). With the earliest appearance in the fossil record of tetrapod features in a fish, the discovery has become a key piece of evidence in the transition from life in water to life on land.

18. Mammals to Humans
Mammals: Mammary glands (milk producing glands for offspring), hair, fat layer under skin, endothermic (high metabolism)
Primates: opposable thumb
Humans: large brain and bipedal locomotion

19. Primates to Humans

20. Invent an Animal-Tuesday
Determine which classification the animal would fall under.
What are the stages of development of the animal?
Why is the organism you created an animal? Explain.
Draw a picture of your animal.

21. Animal Classification Project
You and a partner will:
Create a poster for one classification of animal.
On your poster, use diagrams, charts, words, etc. to explain the:
Key features of your classification of animal.
Why the animal is considered a vertebrate or invertebrate
Development and ancestors of the animal

22. Classifications: Sponges Cnidarians Flatworms Nematodes Molluscs
Annelids
Arthropods
Insects
Echinoderms
Chordates
Lampreys
Jawed vertebrates
Amphibians
Reptiles
Birds
Mammals
Humans