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Pond Water

Pond Water. Lab 2 BIO 101. Evolution via natural selection. What would happen if all of the trees and dinosaurs were the same size?. Individual variation is necessary for natural selection to occur. What would happen if all the dinosaurs produced just one offspring?.

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Pond Water

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  1. Pond Water Lab 2 BIO 101

  2. Evolution via natural selection

  3. What would happen if all of the trees and dinosaurs were the same size?

  4. Individual variation is necessary for natural selection to occur.

  5. What would happen if all the dinosaurs produced just one offspring?

  6. Differential fitness is necessary for natural selection to occur.

  7. What would happen if offspring never resembled their parents? ✖ Parents: Offspring:

  8. Traits must be heritable for natural selection to occur ✖ Parents: Offspring:

  9. Conditions required for natural selection to occur: Individual variation: members of a species differ in their characteristics Mode of inheritance: parents pass on some of their traits to their offspring Differential fitness:some individuals leave more offspring than others due to their special inherited traits

  10. Classification System

  11. We’ll be looking at all of these! Protists are everywhere in Eukarya! “the junk drawer of the eukaryotes” Ancestral Eukaryote

  12. We’ll be looking at all of these! Protists are everywhere in Eukarya! “the junk drawer of the eukaryotes” Ancestral Eukaryote

  13. 6 Kingdoms • Plants (Plantae) • Animals (Animalia) • Fungi (Fungi) • Eubacteria • Archaeabacteria • Protista

  14. A constantly changing system…

  15. Euglena- Heterotrophic and phototrophic (can engulf food via phagocytosis, or use sunlight)- Flagellated

  16. Paramecia- Heterotrophic only - Ciliated- Harbors endosymbiotic green algae that provide food in exchange for protection

  17. Dinoflaggelates

  18. Diatom diversity

  19. Diatom cell wall made of silica

  20. Animals! • Hydra (Cnidaria) • Baby jellyfish that never become adults. • Radial symmetry • Rotifers (Rotifera) • Wheel animals • Bilateral symmetry

  21. A note on symmetry • Bilateral symmetry last to evolve, approx. 555 mya. • Radial symmetry is older, and contains only corals, sponges and jellies.

  22. Phylum Cnidaria – Hydras (Hydra) • Two tissue types, no organs – no anus! • Includes: corals, jellies, sea anemones, and Portuguese men-of-war. (9000+ spp!) • Most species are marine, few freshwater spp. • Generally two body forms present in the life cycle: • Umbrella-like, free-swimming stage (called a medusa) • Cylindrical, attached or stationary form – often grows into colonies of individuals (called a polyp) • Hydra exist only as polyps

  23. Random cool stuff about Hydras • They are capable of morphallaxis • Regeneration into entirely new individuals • Because of this, they might be biologically immortal. • Nematocysts • Cnidocytes are the stinging cells • Explosively discharge harpoon • Contain neurotoxins which immobilize prey • Two body layers • Epidermis on the outside • Gastrodermis on the inside • They’re hermaphrodites • Some have symbiotic relationships with algae Adult medusa

  24. Phylum Rotifera- Rotifers • Very small animals – most 0.1 – 0.5 mm in length • Most common in freshwater, though some salt water species • Important part of freshwater zooplankton, being a major food source and many species contributing to decomposition of organic matter. • Pharynx contains tiny, calcified, jaw-like structure called trophi

  25. Other neat things about rotifers • They have “cement glands” which excrete an adhesive to hold them down. • They have an anus! • They have a brain! (hydra have nerve webs) • They can reproduce sexually or parthenogenetically – development of an embryo without being fertilized (like some reptiles and fish) (also, they’re dioecious– only males and females, no hermaphrodites) • Resting eggs – eggs which develop into zygotes that can survive very harsh conditions (like winter)

  26. Think about… • Morphological characteristics • Ecology of the organism • How does the organism get around? • What role do they play in the ecosystem? • Do they have any economic value? • Where do they live? • Don’t know the answer?? It’s probably a great research question! Ask me about it.

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