General Biology: Chapter 25

History of Life on Earth

Early Earth made what possible?

the origin of life

1st Abiotic Synthesis

small organic molecules (with C & H), physical rather than biological, not derived from living organisms

2nd

joining small molecules into macromolecules

3rd

packaging of larger macromolecules into proto-cells

4th

origin of self-replicating molecules

Instead of forming in the atmosphere, where were the first organic compounds synthesized?

near volcanoes or in deep-sea ocean hydrothermal vents

Protocells

first cells on earth, precursor of cells, made up of RNA replicase and fatty acid membrane

What was the first genetic material?

RNA (ribozymes)

Natural selection produced what?

self-replicating RNA molecules

Geological Record is divided into…

phanerozoic, proterozoic, archaean, and hadean eons

Prokaryotes

first single-celled life forms on Earth

Stromatolites

oldest known fossils, date bac 3.5 BYA

“Oxygen Revolution”

gave Early Earth more oxygen, along with photosynthesis, replenishing Earth’s atmosphere

Eukaryotes

first of these cells date back 1.8 BYA, have nuclear envelope, mitochondria, endoplasmic reticulum & a cytoskeleton

Endosymbiosis

supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events

Evidence supporting Endosymbiosis

mitochondria and chloroplasts have their own DNA and ribosomes

Put the steps that catalyzed the origin of life in order

abiotic synthesis, joining small molecules into macromolecules, packaging of larger macromolecules into protocells

How can something be created genetically?

spontaneously

How is Endosymbiosis true?

take mitochondria, line them up to bacteria and they are the same zine, mitohondria and chloroplasts have 1 DNA inside them

The Cambrian Explosion gave us what?

most animals we have today

Sponges

first animals on Earth

Speciation and Extinction directly affect what?

diversion

Why is Fossil record biased?

it has existed for a long time & organisms had hard body parts such as shells or skeletons

Continental Drift

tectonic plates move slowly, oceanic & continental plates can collide, separate, or slide past each other

Effects of continental drift on living organisms

climate changes as it moves north or south, separation of land masses can lead to allopatric speciation

Mass Extinction

result of disruptive global environment changes

In each of the big 5 mass extinction events, 50% which species became extinct?

marine species

Permian Extinction

defines the boundary between the Paleozoic and Mseozoic eras about 250 BYA

Colonization of Land

Plants and fungi likely colonized land together, fossilized plants show evidence of mutually beneficial associations with fungi