Chapter 25 Flashcards
Planet Age
Earliest Evidence of Life
Planet- 4.6 billion years old
Earliest Evidence of Life- 3.5 billion years ago Fossils of Stromalites- Prokaryotes bound sediments together
4 Steps to the origin of Life
- abiotic synthesis of amino acids and nucleotides
- Molecules join together to form larger molecules such as proteins and nucleic acids
- Larger molecules turn into protobions with membranes that have a different chemical makeup on the inside then on the outside
- Molecules self-replicate, make inheritance of certain alleles or characteristics possible
Gases of the early atmosphere
Methane, ammonia, hydrogen sulfide, water vapor
Oxygen missing because it came from a biological origin and was produced during photosynthesis
A.I. Oparin and J.B.S. Haldane Early organic synthesis source of energy
They believed that it was lightning or intense UV radiation that caused these organic molecules to form, and that the oceans provide source for organic molecules
Miller and Urey Experiment
Water is heated- representing the ocean turning into water vapor
Water vapor enters chamber or methane and ammonia- water vapor enters atmosphere
Sparks released- represents lightning
Water vapor condensed into droplets and analyzed
*Miller and Urey found a variety of amino acids in the samples *
Protobionts
Collections of abiotically produced molecules that are surrounded by a membrane and has a different chemical structure than its environment. Reproduce and metabolize
First Genetic Material and World
RNA- first genetic material
RNA was formed that could hold genetic material in protobionts many further changes and additions to genetic structure were made
RNA then could have mutated from one strand to a double strand- DNA- that is more stable and can reproduce more accurately
Ribozymes
RNA catalysts that cause certain processes such as enzyme-like catalytic functions
In what type of rocks are fossils found?
Sedimentary Rock
How do scientists date fossils
Relative Dating- Order of the Rock Strata to determine relative age of fossils
Radiometric Dating- Looking at half-lives in isotopes to determine how long the fossil has been decaying usually use Carbon-14 (75,000 years old)
If between two layers of volcanic rock, can use potassium-40 on the volcanic rock
Magnetism Shifts- By examining position of particles, can determine what time
Tetrapods
Animals that have four limbs (ex. Mammals, Amphibians and Reptiles)
Differences between Mammals and tetrapods
Lower Jaw bone of mammal- 1 bone
Other Tetrapods- Several bones
Middle Ear of Mammal- 3 bones(hammer, anvil, stirrup)
Other Tetrapods- 1bone
Mammal Teeth- Split into incisors, canines, and multipointed premolars
Other Tetrapods- one row of pointed teeth
Unique Ability of Cyanobacteria
Cyanobacteria became photosynthetic and could produce bacteria
Oxygen damaged the chemical bonds and enzymes of cells– caused mass extinctions of prokaryotes
Steps to the Eukaryote
- Infolding of the plasma membrane
- Enveloping of the nucleus
- Enter of the aerobic prokaryotes and/or enter of photosynthetic prokaryotes
Continental Drift
The theory that the continents moved opver the past thousands of years.Used to be one land mass, and slowly broke away
