Chapter 10 - Life's Origins And Biodiversity

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carbonaceous chondrite

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a class of meteorites containing various kinds of organic molecules

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heterotroph

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an organism, such as an animal, fungus, and most prokaryotes and protists, that takes in preformed nutrients from external sources

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autotroph

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an organism, such as a plant, that can manufacture its own food

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chemoautotroph

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an organism that derives energy from a simple inorganic reaction

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endosymbiont hypothesis

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the idea that mitochondria and chloroplasts originated from prokaryotes that fused with a nucleated cell

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Cambrian Explosion

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in just a few million years at the beginning of the Cambrian period, over 500 million years ago, all of the major animal phyla we see today began to leave preserved remains in the fossil record, in the hundreds of millions of years since, no new body plans have appeared

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Archean Era

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the geological era spanning the time between Earth’s origins and 2.5 billion years ago

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Proterozoic Era

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the geologic era from 2.5 billion years ago to about 580 million years ago

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Paleozoic Era

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the geologic era from about 580 million years ago to 245 million years ago

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plate tectonics

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the geologic building and moving of crustal plates on Earth’s surface

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Pangaea

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a single supercontinent that existed on Earth about 245 million years ago

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end-Permian extinction

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the mass extinction that took place at the end of the Permian period, about 213 million years ago

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Mesozoic Era

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the geologic era from about 245 million years ago to about 65 million years ago

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Cenozoic Era

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the current geologic era, starting about 65 million years ago

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binominal nomenclature

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a system of naming organisms that assigns each species a two-word name consisting of a genus name followed by a species name

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genus

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a taxonomic group of very similar species of common descent

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species

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a taxonomic group of organisms whose members have very similar structural traits and who can interbreed with each other in nature

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family

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a taxonomic group comprising members of similar genera

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order

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a precise arrangement of structural units and activities; also, in taxonomy, a taxonomic group containing members of similar families

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class

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a taxonomic group comprising members of similar orders

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phylum

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a major taxonomic group just below the kingdom level, comprising members of similar classes, all with the same general body plan; equivalent to the division in plants

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division

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a taxonomic group of similar classes belonging to the same phylum, which is often called a division in the kingdoms of plants or fungi

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kingdom

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a taxonomic group composed of members of similar phyla, i.e., Animalia, Plantae, Fungi, and Protista

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domain

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a taxonomic group composed of members of similar kingdoms

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phylogeny

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the study of the evolutionary history of different groups of organisms

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cladistics

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a method of reconstructing patterns of descent using traits or characteristics thought to have evolved only within the group under consideration; for example, hair evolved only in mammals

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clade

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a taxonomic group made up of an ancestral organism and all the descendents derived from it

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ancestral trait

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a trait derived from an ancestral group

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outgroup

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a closely related species whose lineage diverged before all of the members of the group in question; used to infer ancestral traits

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derived trait

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a newly originated inherited change

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analogous trait

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a similar trait possessed by two different groups but not by ancestors of the groups

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homologous trait

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a similarity shared by two species due to inheritance from the last common ancesto

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Bacteria

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one domain including single-celled prokaryotes; the other such domain is Archaea

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Archaea

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a domain including single-celled prokaryotes that have cell membranes and other biochemical and genetic traits different than those of the domain Bacteria

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Eukarya

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the domain including all organisms whose cells possess a true nucleus and other membrane-bound organelles

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Protista

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generally single-celled organisms with nuclei, such as paramecia and amoebas

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Fungi

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the kingdom comprising multicellular heterotrophs such as mushrooms or molds, as well as unicellular yeasts, that decompose other biological tissues

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Plantae

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the kingdom comprising multicellular photoautotrophs such as mosses, ferns, and flowering plants

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Animalia

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the kingdom of animals

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mass extinction

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the disappearance of large numbers of species