3 mammals take over primates evolve and diversify 65

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3) Mammals take over, primates evolve and diversify, 65 may 4) Hominin evolution, 6 million years ago—today Brief history of life on Earth Earth forms 4,600 may Earliest life, 3,600 mya bacteria 3,000 may, photosynthesis Oxygen catastrophe, millions of years ago 1,200 ish, multicellular life (algae) 500 ish, animals Ediacaran Fauna 580-500 may, Cambrian Explosion, major diversification of animal life 485 mya, first vertebrates, jawless fishes 375, vertebrates on land, Tiktaalik rosae ~230, first mammals ~160, first birds last 65 million years, age of mammals
55, first primates fishes (500-250) amphibians and reptiles (around 300) dinosaurs (250–75) 25, apes 6, first hominins mammals (75-0 mya) The basic animal body plan 16 days: embryos start as clump of cells that form a disk 18 days: the disk folds to form two tubes, one for your guts and the other for your brain and spinal chord 22 days: as the neural tube “zips” closed, the location of the vertebrae can be seen. Hox genes that determine the basic body plan are more than 500 million years old same genes in humans, fish, even insects left to right, genes are expressed in the same direction, anteriorly expressed, broad similarities between genes of different species Getting a Head heads of all vertebrates built from the same parts we look similar in the beginning stages between different animals (ex: shark and human) peringial arches (fluffy flaps in front part of beginning tadpole form) become our jaw, ear bones, neck bones brain: cranial nerves from brain, cranial 5 gives you feeling in your face, others work for smell, vision, tongue, trachea Tri-geminal, facial, glossopharyngeal, vagus skull bone are similar, Lungs: Evolved air bladders from fish your lungs develop from your guts because they are an evolved fish air bladders gut and lung formation in a human embryo (lung is small outpouching of gut) vs. gut tract and air bladder in fish Limb development and evolution hox genes also determine basic limb plan segment identity: upper arm, forearm, hand Mammals: DNA phylogeny our closest relatives are apes, monkeys, and other primates Primate Origins: Why and how did early primates evolve?
Two competing hypotheses, Carpolestes 55 mya, early fossil primate species, climb high on trees, grasping hands and feet, big eyes to see well in the dark and overlapping visual fields for depth perception, eat fruits and insects Angiosperm co-evolution: fruiting plants and primates coevolve, plants provide a food source (fruit), primates help disperse their seeds (poop out seeds), insects, air, water, Nocturnal Visual Predation: binocular vision and grasping hands evolve to hunt insects at night nocturnal insect hunting is common in small-bodied primates The primate family Tree primates split from other mammals 80 mya, early fossil primates separate into haplorhines and strepsirhines, earliest monkeys in 40 mya, earilest apes in 15 ya, apes, old world monkeys, new world monkeys, tarsiers, lorises, lemurs What is a hominin?

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