Genetics Flashcards
(22 cards)
When did Earth form?
Earth formed about 4.6 billion years ago.
What was the early environment of Earth like?
The environment was too hostile for life until 3.9 billion years ago.
What was the composition of the early atmosphere?
The early atmosphere was mostly methane, ammonia, and water vapor.
What geological activity was present in the early atmosphere?
Volcanic activity.
When does the earliest fossil evidence for life date back to?
The earliest fossil evidence for life dates back 3.5 billion years ago.
What is abiogenesis?
Abiogenesis is the idea that life could arise from non-living matter.
What is panspermia?
Panspermia is the hypothesis that life comes from another planet and landed here by an asteroid.
What is spontaneous generation?
Spontaneous generation is the idea that life forms can arise spontaneously from non-living matter.
What did the Miller-Urey experiment demonstrate?
The Miller-Urey experiment showed that organic compounds could be produced from inorganic compounds in a primitive environment.
What allowed organic substances in the atmosphere to combine in the oceans?
A large amount of energy.
What were the first cells?
The first cells were prokaryotic.
What did simple molecules form?
Simple molecules formed more complex structures and eventually became the first living cells.
What type of respiration did early life forms carry out?
Early life forms carried out anaerobic respiration.
What is the heterotroph hypothesis?
The heterotroph hypothesis suggests that early life forms were heterotrophs.
What does the endosymbiotic theory propose?
The endosymbiotic theory proposes that eukaryotic organelles originated as free-living prokaryotes that were engulfed by an ancestral eukaryotic cell.
What evolved about 2.5 billion years ago?
Cyanobacteria evolved the ability to carry out photosynthesis.
What was the result of the Great Oxidation Event?
Free oxygen caused worldwide deposition of iron oxide formation.
What increased due to an oxidizing atmosphere?
Weathering increased due to an oxidizing atmosphere.
What type of organisms evolved that depend on oxygen for respiration?
Aerobic organisms.
When did eukaryotic cells evolve?
Eukaryotic cells evolved about 2 billion years ago.
What significant event occurred 541 million years ago?
The Cambrian explosion was a great diversification of marine animals.
When did modern humans appear?
Modern humans appeared very recently, approximately 200,000 - 300,000 years ago in Africa.
