explain the chemical evolution hypothesis
life on earth developed gradually from nonliving matter through a series of chemical reactions
Describe the contributions made by Oparin
& Haldane, and Miller & Urey toward
understanding the origin of organic
molecules
Oparin and Haldane - created the chemical evolution hypothesis and laid the foundation for miller and Urey who experimentally produced amino acids from gases thought to exist on early earth using electric sparks
why was rna first genetic material not DNA
ran can both store information and catalyze reactions
In the 1920s Oparin and Haldane
postulated that:
Primitive earth favoured chemical reactions
* Atmosphere was reducing (adding electrons to
atoms and molecules)
chemical evolution hypothesis steps
1.) abiotic synthesis and accumulation of small organic molecules
2.) joining of monomers into polymers
3.) aggregation of macromolecules into “ probionts”
4.) origin of heredity
- self replicating molecules
- may have ben rna based at first
protocols aka protobionts
- not capable of precise reproduction
- aggregates of abiotically produced molecules
e.g - liposomes
anagenesis
gradual evolutionary change of a single “lineage” over time leading to the transformation of one species into another
cladogenesis
Cladogenesis is the evolutionary process where a single ancestral species splits into two or more new, distinct species, forming a branching evolutionary pattern.
allopatric speciation
being separated by a physical geographical barrier ex the squirrels inn the canyon
sympatric speciation
evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic area
how does polyploidy cause reproductive isolation
making polyploids unable to successfully reproduce with individuals from the parent population due to differing chromosome numbers
multicellular life - cells began to form colonies and specialized leading to multicellular organisms
Fossilized algae and other early multicellular organisms
Molecular clock studies showing divergence of multicellular lineages
Photosynthesis and oxygenation (~2.5–2.0 billion years ago) Cyanobacteria evolved photosynthesis, producing oxygen as a byproduct.
Banded iron formations (rocks formed by oxygen reacting with iron)
Fossilized cyanobacteria
