The Origin and Evolutionary History of Life

Question 1

Chemical evolution requires

Answer 1

1: the absence of oxygen, which would have reacted with and oxidized abiotically produced organic molecules; 2) energy to form molecules; 3) chemical building blocks, i.e. water, gases, minerals; 4) sufficient time for molecules to accumulate and react.

Question 2

The prebiotic soup hypothesis

Answer 2

It proposes that organic molecules formed near Earth’s surface in a “sea of organic soup” or on rock or clay surfaces.

Question 3

The iron-sulfur world hypothesis

Answer 3

Organic molecules were produced at hydrothermal vents, cracks in the deep-ocean floor.

Question 4

Protobionts

Answer 4

Macromolecular assemblages formed from macromolecules which is thought cells arose from them.

Question 5

RNA world

Answer 5

RNA was the first informational molecule to evolve in the progression toward a self-sustaining, self-reproducing cell. Natural selection at the molecular level eventually resulted in the information sequence DNA-RNA-Protein.

Question 6

Photosynthetic autotrophs and atmosphere

Answer 6

The accumulation of molecular oxygen in the atmosphere permitted the evolution of aerobes, organisms that could use oxygen for a more efficient type of cellular respiration.

Question 7

Serial endosymbiosis

Answer 7

Eukaryotic cells arose from prokaryotic cells. According to the hypothesis certain eukaryotic organelles (mitochondria and chloroplasts) evolved from prokaryotic endosymbionts incorporated within larger prokaryotic hosts.

Question 8

Proterozoic eon

Answer 8

Life began consisting of prokaryotes. About 2.2 bya, the first eukaryotic cells appeared.
The Ediacaran period is th last period of this eon and the oldest fossils of multicelular animals belong to this period.

Question 9

Paleozoic era

Answer 9

All mayor groups of plants, except flowering plants, and all animal phyla appeared. Fishes and amphibians flourished and reptiles appeared. The greatest mass extinction occur at the end of this era.

Question 10

Mesozoic era

Answer 10

Flowering plants appeared, and reptiles diversified. Dinosaurs dominated. Insects flourished, and birds and early mammals appeared. At the end of the Cretaceous many species died as a result of a meteorite.

Question 11

Cenozoic era

Answer 11

The youngest era, flowering plants, birds, insects and mammals diversified greatly. Human ancestors appeared in Africa during late Miocene and Early Pliocene epochs.

Question 12

Trilobites aparición

Answer 12

Cámbrico, ordovicico, devonico

Question 13

Cefalopodos ammonites Origen

Answer 13

Permico Triassic