Explorations Through Time – Life Has History – Flashcards
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How many different species of living things exist today?
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More than 30 million.
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Which group of animals has the largest number of species?
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Arthropods
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How many mammal species exist today?
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More than 4,000
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What is biodiversity?
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The many type of organisms that exist.
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470 million years ago
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•Ordovician period •Dominant predator: Cephalopods •First arthropod: Trilobites
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160 million years ago
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•Middle Jurassic period •Larget marine reptile existed during that time: Ichtyosaur
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How old is the Earth?
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Over 4 billion years
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What is the best source of evidence for determining events in Earth's history?
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Fossils
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What is a paleontologist?
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They study fossils to learn about past life.
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What is a cladogram?
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A branching diagram that shows how each group of animals is related to the others.
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What is divergence?
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The splitting of one species into two or more species.
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What other data (besides physical features) do scientists use to find if organisms are related?
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Behavior, embryology, and DNA.
