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L2 Animal Diversity Making sense of diversity. Linnaeus. Key. fins or legs?. legs. fins. amniote?. yes. bone/cartilage?. scales?. no. no. cartilage. bone. yes. hair/feathers?. hair. feathers. shark. frog. fish. mammal. bird. crocodile. fins. bone. Key. fins or legs?.
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L2 Animal Diversity Making sense of diversity
Key fins or legs? legs fins amniote? yes bone/cartilage? scales? no no cartilage bone yes hair/feathers? hair feathers shark frog fish mammal bird crocodile
fins bone Key fins or legs? bone/cartilage? fish
Key fins or legs? legs fins amniote? yes bone/cartilage? scales? no no cartilage bone yes hair/feathers? hair feathers shark frog fish mammal bird crocodile
Keys need not reflect evolution mammal bird crocodile frog fish shark
Paraphyletic groups are often grouped by the absence of something
Whittaker’s Five Kingdom Classification (1969) photosynthesis absorption ingestion Classification based on cell structure and methods of nutrition
Evolutionary tree for all of life Constructed from ribosomal RNA sequences
The Deep Roots of Eukaryotes, S. L. Baldauf, Science Jun 13 2003: 1703-1706
Protists are “paraphyletic” Protists are those eukaryotes left over after we remove plants, fungi, and animals
alveolates The Deep Roots of Eukaryotes, S. L. Baldauf, Science Jun 13 2003: 1703-1706
Red tides - massive dinoflagelate blooms causing massive fish deaths (need piccies of red tide)
Apicomplexa: Malaria Each year 300 million people are infected, and 2 million die
Malaria is an ancient disease 10-20 Myr falciparum Human Phylogeny of the genus Plasmodium reichenowi Chimp gallinaceum Bird lophurae Bird mexicanum Lizard malariae Human fragile Monkey 150 Myr knowlesi Monkey 41 Myr vivax Human cynomolgi Monkey berghei Rodent
Coccoliths • Emiliania huxleyi is planktonic • On death cells clump together and sink to the ocean floor • Massive carpets of coccoliths cover the ocean floors
Emiliania huxleyi off the coast of Newfoundland, 21st July 1999
Neogloboquadrina pachyderma Left or right coiled shell depending on water temperature Right-coiled (Dextral) specimen, umbilical view Percent right-coiling N.pachyderma 10% 20% 30% 40% 50% 60% 70% 80% 90% 0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 Left-coiled (sinistral) specimen, umbilical view
Trypanosoma Causes African sleeping sickness in humans Red blood cells Trypanosomes
Diatoms Glasslike walls made of hydrated silica. Skeletons for “diatomaceous earth” which is used for filters.
Similarity between sponges and choanoflagellates Colonial choanoflagellates
Summary • Keys enable us to identify organisms • Keys are not classifications • Groups defined by not having features of another group often comprise unrelated organisms (paraphyletic) • The protists are a classic case of a diverse but unrelated group of organisms