Evolution of life(Astrobiology) Flashcards
- Proto-Earth
Started as a kilometer-sized piece of debris that came from the proto-star, sun.
Started to accrete debris, growing in size and producing heavier metals that sunk inwards, forming the core and mental of our planet.
There was no air or water and it was composed of just volcanoes and lava.
- Atmosphere Forms
Helium and hydrogen were not found on earth, they were too far away from the gravitational pull to be affected.
Volcanoes on earth began to release heavier, volatile gasses such as carbon dioxide, methane, and sulfur dioxide.
Collusions from meteoroids brought water vapor and nitrogen, which mixed with the gases on the earth and created the atmosphere.
- First Life
From the creation of atmosphere, the first cyanobacteria and DNA- based archaebacteria evolved.
It started the process of photosynthesis, thus bringing oxygen to earth and causing oceans to form.
Life was still too complex to evolve.
- Life Advances
Bacteria grows stronger as it evolves into multi-cellular bacteria.
Earth goes through the first few ice ages and meteor showers.
Species of bacteria come and go.
- Cambrian Explosion
Cratons(sentiments of rocks) form on earth, creating land.
Atmosphere is oxygen rich on earth. Bacteria developed into the first living aquatic species.
- First Animal
Trilobites—Date back to 500 million years ago.
First vertebra (fish) to develop. They grew only larger.
- Land Becomes Habitable
A supercontinent is formed on earth.
Plants and fungi colonize and first mammals evolve into mammals with four legs to which they could explore the new lands with.
the first four legged mammals were called tetrapod.
- Land Mammals Evolve
Predominantly lizards and reptiles(dinosaurs) habitat the earth this point due to the new, dry living conditions of earth.
After the extinction of the dinosaurs, the continents drift and smaller mammals begin to thrive(turn into Primates).
- Climate Shifts
Climates gets hotter and drier, rain forests turns into savannah grasslands.
Primates evolve into bipedal animals(walk on two legs)
climbers to walkers.
Hominids develop.
- Grasslands recede
Hominids lose har, develope taller/thinner bodies with longer legs.
Due to the increase of deserts, hominids adapted.
Primates cranial activity grows and they learn to cook, hunt, co-exist, use tools, and form communities.
- Last Common Ancestors
Sapiens, neanderthals, devisavons begin to journey and seek Habitable climate in the Great out of Africa Migration.
Homo-sapiens out-populated the others.
Copernican Princple
The theory that the solar system revolves around the sun, and not the earth.
The sun was the center of the universe.
(Some discoveries that prove this is the phases of Venus, and moons that orbit other planets.)
Atoms
Originated from the materials of a supernova and make up the whole world.
Biomarker
A visible sign of life.
(examples include light, the color green, water)
What makes space travel difficult
It takes a long time to traverse space, too long
Too much time!
