2. Kingdom Animalia Two groups of animals have appeared in the fossil record, a very ancient one and a more modern one. From 700-900 million years ago, a whole world of animals thrived in the oceans, but their fossils disappear about 600-650my ago. A few survived, and became the ancestors of modern animals. All modern animals groups can be traced back to the beginning of the Cambrian Period, about 600 million years ago.

5. Animalia Traits: Heterotrophic--have to ingest (eat) then digest food multicellular but NO CELL WALLS adult is always diploid motile--can move around have sexual reproduction only haploid cells are large, non-motile eggs and smaller, motile sperm

6. How we classify animals: Symmetry--radial or bilateral complexity of organism-- tissues/organs/systems absent or present backbone or internal skeleton-- absent/present number of layers developing from zygote coelom (body cavity) absent/present segmentation absent/present

7. Invertebrates vs. Vertebrates Does the animal have a backbone (spinal chord) or some primitive form of one during development? Ex. those with: us, fish, sharks Ex. those without: jellyfish, politicians

8. Sponges Sponges-- simplest animals evolved multi- cellularity get food by filtering water for organic materials

9. Jellyfish have tissues (but not organs or systems) and symmetry have two layers of tissues developing from zygote: endoderm and ectoderm have nerves and muscles (both are tissues) have plant-like alternation of generations life cycle

10. Next steps: bilateral symmetry evolved Then organs evolved from groups of tissues Flatworms-- forms tube- within-a-tube body plan

11. And then... an internal body cavity (a coelem) for protection of organs, digestion, and reproduction those that did went on to evolve producing a mouth (protostomes) or an anus first and then a mouth (deuterostomes) some lower animals evolved a false coelem, a pseudocoelem (=pseduocoelemates): ex. roundworms

12. 3 groups of protostomes: molluscs (snails, squids) annelids (earthworms) arthropods (insects, crabs, spiders)

13. Molluscs 3 groups within molluscs: 1. Clams, oysters (bivalves)--filter water for food. 2. Cephalopods (squid, octopus)--most advanced molluscs-- have closed circulatory systems and well- developed nervous systems. 3. Gastropods (snails, slugs)--

14. Some early animals evolved segmentation ex. Annelids (earthworms)--this allows specialization of different segments for reproduction, etc. ex. Arthropods (insects, spiders)-- have a tough exoskeleton for protection, can increase body size through metamorphosis (like caterpillars  butter- flies)

15. Arthropod groups: 1. Chelicerates-- spiders, scorpions, ticks 2. Crustaceans-- shrimp, lobster, crabs 3. Uniramia-- millipedes, centipedes 4. Insects-- grasshoppers, ants, bees

16. Deuterostomes--those that produce an anus first, then a mouth Two groups-- echinoderms (no true endoskeleton) and chordates (those with true endoskeletons )

17. Echinoderms sea stars, starfish have a well-developed coelem and internal organs each arm has its own digestive and reproductive organs, and an eyespot at the end no respiratory, excretory, or circulatory systems-- internal water movement does all this

18. Chordates: all have internal skeletons, plus 3 main requirements: 1. A dorsal (back) hollow nerve cord (the future spinal cord) 2. A notochord--a supporting rod for nerve cord; notochord later replaced by vertebrae. 3. Pharyngeal pouches--only present in embryos. In humans, the 1st pair become ear tubes, the 2nd the tonsils, and the 3rd & 4th become the thymus glands and parathyroids

20. Other Chordate traits: Usually 2 pairs of jointed appendages internal skeleton that grows with organism skull protects brain complex sensory organs (eyes, ears, etc.) closed circulatory system

21. Major Chordate groups: 1. Fish--3 groups: jawless, cartilage, and bony. 2. Amphibians--frogs, salamanders 3. Reptiles--snakes, lizards, alligators 4. Birds 5. Mammals

22. Mammary glands

23. Fish: 1 st Chordates 3 groups: jawless, cartilaginous, and bony jawless--ex. Lamprey eels cartilaginous--ex. Sharks, rays jawed--ex. Salmon, bass, trout Fish ancestors, which were jawless, evolved the jaw from modified gill support bones

24. Jawed fishes: Skeletons of bone scales made of modified bone cells gills covered by operculum swim bladders color vision! 2-chambered heart with a single loop of circulation

25. Amphibians: Amphibians are basically lobe-finned fish that made it onto land evolved some unique features: 1. Tongues 2. Eyelids 3. Ears 4. Voices 5. Highly developed brains 6. Double-loop circulatory system with 3-chambered heart 7. But have to return to water to lay eggs

26. Birds: Kept many reptilian features, such as amniotic eggs and scales (on feet and face) only modern animals with feathers endotherms--have high body temperature regardless of external temperature 4-chambered hearts complete ventilation

27. Mammals: Evolved from “stem reptiles” large brain size to body ratio have differentiated teeth highly differentiated vertebrae mammary glands homeothermy hair 4-chambered hearts

28. 3 kinds of mammals: 1. monotremes—lay eggs 2. marsupials— embryos have to crawl to milk glands located in a pouch 3. placentals— embryos attach via placenta to mother for nutrition; completely enclosed until birth

29. Placental mammal groups: Rodents--mice, beavers; large front teeth hoofed mammals--horse group and cow group rodent-like--rabbits carnivores--dogs, cats, bears cetaceans--whales, dolphins modified upper lips & noses--elephants primates-us, chimpanzees, apes

30. Primates: Grasping hands/feet Binocular vision—allows for 3-dimensional viewing; helpful in forest environments for going from tree to tree Reduction in snout/nose length Teeth evolved for eating both plant and animal tissues (=omnivorous)

31. The evolutionary path to us:

32. Human evolutionary tree based on skull characteristics 700,00 0 years ago 1.5 million years ago 2.9 million years ago