Unit One: Life on Earth Flashcards
What is said to be life’s origin?
various meteorite strikes
What meteorite has been said to fall from mars to earth with extraterrestrial life?
ALH84001
4 +3/4 lbs, formed by molten lava
What are the two types of life?
1. Biotic (living)
2. Abiotic (non-living)
What are the biotic characteristics of viruses
- nucleic acids
- ability to reproduce and replicate
- ability to evolve and adapt
What are the abiotic characteristics of viruses
- cannot synthesize their own proteins
- cannot live without host attatchment
- cannot reproduce
What are the characteristics of all life forms?
- Display orderly fashion
- Harness and utilize energy for mechanical purposes
- Reproduction
- Responding to stimuli
- Homeostasis
- Growth and Development
- Evolution
What are some characteristics of the earth
- earth is 4.6 billion years old
- first prokaryotes: 3.5 billion years
- first eukaryotes: 2.0 billion years
- dinosaur extinction: 65 million years
- modern humans: 150,000 years
What are the 4 classes of molecules
- Nucleic Acids (DNA, RNA, ATP)
- Proteins (amino acids)
- Lipids (fats)
- Polysaccarhides (carbohydrate)
What are the 3 hypothesis’ to early years of earth
- Reducing Atmosphere
- Deep Sea Vents
- Extraterrestrial Origin
Reducing Atmosphere Hypothesis (1)
- beginning (primordial) atmopshere
- water vapour (H2, CO2, NH3, CH4)
- almost complete absence of O2
What is the Oparin-Haldane Hypothesis
- early atmosphere was reducing (eliminating O2 and O3)
- simple organic molecule formation
- amino acids first –> complex polymers
- molecule development through UV light
What is the confirmed modern atmospheric content
- oxidizing atmosphere
- high levels of O2 prevents formation of complex molecules
Deep Sea Vents Hypothesis (2)
- complex organic molecules originated on ocean floor through deep sea vents
- cracks near volanic activity
- produces nutrient rich water
- NH3, CH4, H2S
Extraterrestrial Origin Hypothesis (3)
- key organic molecules originated from outer space
- organic molecules: carbon based
- carbonaceous chondrites: meteorites with organic molecules
Earliest Form of Life: Heterotrophs
- heterotrophs
- organisms containing organic molecules
- consumers
- earliest forms were considered anerobic