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Early Anthropods

Early Anthropods. Anthropods emerge from sea Preadapted- possessions of adaptations usable for life on land by chance ie- exoskeletons- waterproof Breathing- development of tracheae (small tubes with adjustable holes in the exoskeleton for air)

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Early Anthropods

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  1. Early Anthropods • Anthropods emerge from sea • Preadapted- possessions of adaptations usable for life on land by chanceie- exoskeletons- waterproof • Breathing- development of tracheae (small tubes with adjustable holes in the exoskeleton for air) • Tens of millions of years- anthropods dominated the land (millipedes, dragonflies)

  2. Early Amphibians • 400 million years ago- lobefins appeared- fresh water major preadaptations- fins, pouch used for lung • One group of lobefins, the lung formed into a swim bladder and they returned to sea • First amphibian fossil record about 350 million years ago • Skin had to be kept moist because oxygen came through the skin • Sperm and eggs could not survive in dry habitat

  3. Early Reptiles • Four great adaptations to reptiles- internal fertilization, shelled waterproof eggs, scaly waterproof skin, improved lungs • Evolution from early reptiles into dinosaurs- carnivores, herbivores • Dinosaurs flourished for more that 100 million years- extinction unknown, maybe climate change caused by meteorite impact • To prevent heat loss, some reptiles developed feathers or even hair

  4. Early Birds and Mammals • Insulating feathers retained body heat which was important • At first, gliding birds started, then flight was produced • Mammals had hair for insulation also • Unlike birds and reptiles, mammals evolved live birth and offspring feeding using mammary glands • Since hair, mammary glands, uterus fossilize, we will not know when it evolved • 55 million years ago, hair was found in fossilized feces • Early mammals were small, tree-living ones- eventually, tree-living mammals stayed there and gave rise to primates

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