CHAPTER 2.2 Origin of Earth's Ocean

Question 1

BigBang Theory

as the universe cools, protons, and neutrons can fuse to form heavier atomic nuclei

Answer 1

nucleosynthesis

Question 2

Early Earth

1. Formed via — of grains of dust and gas
2. Original proto-Earth was — material (Ni and Fe) that flowed to the center
3. Lighter material (molten Si) flows to the —.
4. Earth cools and solidifies into — structures.
5. Overall density of the earth is – g/cm3
6. Earth has a lot of trapped gases (in the form of —) in its interior - the one that undergo radioactive decay (because it needs to release heat, volcanic activity was more seen/ more volcanic outgassing)

Answer 2

accretion
molten dense
top
core, mantle, and crust
5.5 g/cm3
isotopes

Question 3

• formed about 4 bya
• its early forms was believed to derived from —-
• composed of mostly: H2O, CO2, CO, N2, HCl, SO2, Cl2, NH3, CH4, S2 (in the form of dust, vapor etc)

trace amounts of free oxygen is absent, although, it was combines with other compounds

Answer 3

atmosphere
volcanic outgassing

before the ocean formed, the atmosphere must form first

Question 4

Steps of Volcanic Outgassing forming oceans

As erupted, the elements will be — on the earth’s surface.
When combined together, — etc are formed because of UV light or photolysis - this lies molecules, becoming free from each other, then begin to combine with another to become stable
Elements circulate around from eruption forms —
More volcanic activity, more chemical surroundings
More planetary albedo (how much of light is reflected back) the more volcanic outgases, more chemicals forming aerosol results in —, because of aerosol presence, the sunlight that will touch it will be reflected back (some are escaped but most are reflected)
More aerosol are circulating around the earth, increasing light/photons being reflected causing the cooling of temperature of early atmosphere
Due to planetary cooling. condensation and precipitation of acid rain occured
However, initial precipitation — upon hitting the still hot planetary surface
This continues for millions of years, until finally. by —, water collected into warm seas and oceans above and around cooling crustal rock

Answer 4

scattered
water vapor, sulfuric and hydrochloric acid, H2Cl,
aerosol
increased planetary albedo
vaporized
3.8 - 3.6 bya

Question 5

Origin of Ocean

2 Theories on Oceans’ Formation
1. Earth was — and that this came from inside out.
2. Earth was a — with water brought by other sources.

Answer 5

formed with water
dry planet

Question 6

Sources of Ocean Water

1. Separated out from the — that make up the bulk of the earth
2. Arrived as part of a late-accreting veneer of — similar to the carbonaeous chondriites that we see today
3. Arrived as part of late-accreting veneer of icy planetary debris - —

Answer 6

rocks
water-rich meteorites
comets

although it starts raining, it is acid rain which is toxic because of volcanic outgassing

Question 7

aqueous solution of organic compounds that accumulated in primitive water bodies of the early earth as a results of endogenous abiotic syntheses and the extraterrestrial delivery by cometary and meteoritic collisions, and from which some have assumed that the first living systems evolved (lipid, nucleotide, amino acid precursors)

It is thought that Earth’s original blend of gases produced a broth of organic molecules when exposed to light and heat, eventually forming the building blocks of life in amino acids

Answer 7

primordial soup of life

Question 8

Clay: Birthplace of Life on Earth

the cycling of — molecules from the ocean and — molecules from clay manifested biomolecules

^ oxidized (loss electron)
v reductive (gains electron)

-space between clay sheets - RNA breeding grounds

Answer 8

oxidized
reductive

Question 9

-more mono/polymers - fatty acid -> cell membrane
-amino acids ->primary amino acids - beta sheets ->tertiary proteins - specific proteins
-these molecules were enclosed within —, forming primitive proto-cellular life
-unstable RNA -> DNA formation
-resulted in the appearance of —- (photosynthetic) -> forming — (conglomerates) -> releasing intense oxygen, and polluting the atmosphere with — -> becomes the progression of life on earth

Answer 9

lipid membranes
cyanobacteria
stromatolites
free oxygen

Question 10

Endosymbiotic Theory

— are actually the descendants of separate prokaryotic cells that joined together in a symbiotic union

— one organism taking up permanent residence inside another and eventually evolving into a single lineage

Answer 10

eukaryotic cells
internal symbiosis

ancestral host cell engulfs aerobic bacterium and cyanobacteria - gives rise to modern cells; cyanobacteria - chloroplasts and aerobic bacterium - mitochondria
one prokaryote engulfs one mitochondira - evolved as single lineage leads to heterotrophic organisms
prokaryote have own mitochondria, engulfs another prokaryote and live together as single lineage - autotrophs - algae protists and plants
Kwang Jeon