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Fossils found in Antarctica? PowerPoint Presentation
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Fossils found in Antarctica?

Fossils found in Antarctica?

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Fossils found in Antarctica?

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  1. Fossils found in Antarctica? Today, Antarctica is covered in ice. Why are scientists finding fossils of plants and other wildlife? Fossilized Fern Fossilized Dinosaur Jaw Bone

  2. Fossils are found all over the world!

  3. Biogeography • The geographic distribution of living organisms • Fossils that occupy continuous areas can indicate common ancestry among species that live on different continents!

  4. Now that the continents have separated… Do you think populations are still evolving?

  5. The Galapagos Islands • Each island in the Galapagos has similar organisms, but they’re different enough to be different species. • Have they always been different species? • Or, did each species evolve from a common ancestor from the mainland (Ecuador)?

  6. How & why did species on the Galapagos evolve? i. Each island habitat has different selective pressures acting on the organisms.

  7. How & why did species on the Galapagos evolve? ii. Natural selection acts on the populations separately, which over time, causes the populations to diverge morphologically and physiologically. Food on Hood Island is sparse, so turtles are smaller. Their saddle-backed shells allow them to lift their necks higher to reach vegetation. Food on Isabela Island is common & can support larger turtles.

  8. Are all organisms that look the same related? NO! • Organisms that are unrelated in the same types of habitats elsewhere in the world had the same selective pressures acting on them, & therefore, developed similar characteristics. • Analogous Structures!

  9. How long has this been happening? • Scientists have created the Geologic Time Scale which identifies major events that occurred in the past. Fossil record shows us that Earth is about 4.6 billion years old!

  10. (millions of years ago) Era Period Time Key Events Cenozoic Mesozoic Paleozoic Precambrian Time Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian 1.8–present 65–1.8 145–65 208–145 245–208 290–245 363–290 410–363 440–410 505–440 544–505 650–544 Glaciations; mammals increased; humans Mammals diversified; grasses Aquatic reptiles diversified; flowering plants; mass extinction Dinosaurs diversified; birds Dinosaurs; small mammals; cone-bearing plants Reptiles diversified; seed plants; mass extinction Reptiles; winged insects diversified; coal swamps Fishes diversified; land vertebrates (primitive amphibians) Land plants; land animals (arthropods) Aquatic arthropods; mollusks; vertebrates (jawless fishes) Marine invertebrates diversified; most animal phyla evolved Anaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life The Geologic Time Scale

  11. Before you leave… • On a sheet of paper (share!), describe why this cartoon is inaccurate.