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Bell Question. What kinds of features are helpful in determining how related two organisms are? Answer on the back of your sheet Do not hand it in when you finish!. Phylogenetic Trees. Shows the evolutionary relationship between organisms over time.

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Bell Question

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  1. Bell Question What kinds of features are helpful in determining how related two organisms are? • Answer on the back of your sheet • Do not hand it in when you finish!

  2. Phylogenetic Trees • Shows the evolutionary relationship between organisms over time

  3. The root of the tree represents a common ancestor • The tips of the branches represent the • descendants of that ancestor • As you read from roots to tips, you move forward in time

  4. Each node represents an ancestor that the descendants have in common • The descendants split and became two separate organisms after their most recent common ancestor

  5. The organisms that share the most recent common ancestor are the most closely related

  6. We can include traits on the tree to show where they have evolved

  7. You try it! Get into groups of 4

  8. Make a phylogenetic tree of the following technologies • Remember that the tree goes from oldest at the root to most recently “evolved” at the branch tips • Cell Phones • Telephone (landline) • Telegraph (Morse code) • Blackberry • iPhone • Smoke signals Label at least five “traits” that evolved on your diagram

  9. Homework • Make your own phylogenetic tree of invertebrates (this example is on the website) on a large piece of paper • Do not need traits • Need colours, names, and pictures (can be drawn, can be cut and pasted)

  10. Spectacular Sponges!

  11. Aquatic animals • Phylum name Porifera means “pore-bearer”

  12. Level of organization: • Cellular • Life activities distributed among a number of specialized cells • These cells are not coordinated • No tissues

  13. Body Plan • Symmetry: asymmetrical • Osculum: large opening which lets water out • Ostia: tiny holes which let water in • Spicules: needles of silica which forms the skeleton of the sponge

  14. (Video)

  15. Digestion • Done by collar cells • Food and water enter the sponge through the ostia • The collar cells trap and digest the food • Amoeboid cells transport food throughout the sponge

  16. Circulation • Circulation, respiration, and excretion are carried out by diffusion

  17. Nervous System • No head • No nervous system

  18. Reproduction • Sponges can reproduce both sexually and asexually • Sexual reproduction: • Female releases eggs into the water and male releases sperm • The sperm swims to the egg and fertilizes it • The fertilized egg (zygote) drops to the bottom and grows

  19. Reproduction • Asexual: • Buds (small, new sponges) develop on the adult • Buds drop off and develop into new sponges

  20. Motility (movement) • Sponges are sessile, meaning they do not move

  21. Ecology • Shelter for other species (mostly small invertebrates) • Filter feeders: filter bacteria out of the water • Release chemicals that break up old shells and dead coral – recycles calcium • Food source for some species of snails, sea stars, and fish

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