Vocabulary Chapter 20

1.Angiosperm:are the most diverse group of land plants.

2.Archeabacteria:  are a group of single-celled microorganisms.

3.Archean Eon:  is ageologic eon before the Paleoproterozoic Era of the Proterozoic Eon

4.Big Bang: model or theory is the prevailing cosmological theory of the early development of the universe.

5.Cenozoic Era:  is the current and most recent of the three classic geological eras and covers the period from 65.5 mya to the present. 

6.Crust, of earth:  is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle.

7.Dinosaur: are a diverse group of animals that were the dominant terrestrial vertebrates for over 160 million years, from the lateTriassic period.

8.Ediacaran: is the last geological period of the Neoproterozoic Era and of the Proterozoic Eon,

9.Endosymbiosis theory:concerns the mitochondria, plastids (e.g. chloroplasts), and possibly other organelles of eukaryotic cells. 

10. Eubactirium:  are a large domain of single-celled, prokaryote microorganisms. 

11.Eukaryotic Cell: have cell walls; many do not.

12. Global broiling hyphotesis: is the current rise in the average temperature of Earth's oceans and atmosphere and its projected continuation. 

13. Gymnosperm:  are a group of seed-bearing plants that includes conifers, cycads, Ginkgo and Gnetales.

14.K-T asteroid impact theory:  is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet.

15. Mantle: is a part of a terrestrial planet or other rocky body large enough to have differentiation by density.

16.Mesozoic era: is an interval of geological time from about 250 million years ago to about 65 million years ago.

17.Paleozoic era: is the earliest of three geologic eras of the Phanerozoic Eon. 

18.Prokaryotic cell:  are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. 

19.Proterozoic eon: is a geological eon representing a period before the first abundant complex life on Earth. 

20.Protistan:are a diverse group of eukaryotic microorganisms.

21. Proto cell:  is the study of how biological life arises from inorganic matter through natural processes, and the method by which life on Earth arose.

22. RNA world: proposes that life based on ribonucleic acid (RNA) predates the current world of life based on deoxyribonucleic acid (DNA), RNA and proteins.

23. Stromatolite:  are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.