Lecture 2 Flashcards
Formation of the sun
Hydrogen -> helium = sun + energy
Ring around the sun due to gravity
Protoplanetary disk
A cloud of disk containing hydrogen and helium, supa nova event, stars are destroyed, sun is in the center, allow preplanet
Protoplanet
Gravity from the sun, 4.6 bya
Precambrian supereon
Divided into three eons, 2nd two eons are divided into eras
Paleozoic era
543 mya to 250 mya
Mesozoic era
250 mya to 65 mya
Cenozoic era
65 mya to now
Hadean eon
He’ll towards end: cloud forms, steam from core
Uninhabitable
Archean eon
Arches and bacteria live
Cyanobacteria mats/ stromatolites
Unicellular
Unicellular vs multicellular
1 bya multicellular arises in late Precambrian eon
Trilobites
During Paleozoic era
Archeocyanthids
Started the animal tree; led to the modern sponges
1st plants
Cambrian period
1st land animals
Cambrian period
They were amphibians
Permian extinction
Oxygen level dropped, about 60% extinct
Age of reptiles
250 mya to 65 mya
1st mammal
Mesozoic 200 mya
Morganucodon watsoni
K-T extinction event
65 mya
Associated with KT boundary
Caused by 1 or more catastrophic event
Reduced sunlight, no photosynthesis
Geological clock
Earth’s history is very long
Precambrian most if the clock
Continental drift
Oxygen level changes
Climate changes
Parallel time scale
Forcing continents together or apart
What is life?
- Organized
2. Replicated itself
Four steps to form life
- Abiotic synthesis of organic material
- Formation of polymers
- Formation of protobionts
- Origin of heredity materials
Miller and Urey’s experiment
1955
Reproduced the conditions of young earth
Was wrong
Earth was dominated by CO2 and N2
