Define natural selection
Natural selection is the process by which traits that enhance survival and fitness are transferred to new generations at a higher rate than others due to their benefit to the organism
Explain how corn was developed from teosinte using artificial selection?
Through selective breeding humans were able to artificially select corn that was beneficial as a food source. This produced the corn we see today.
What is fitness in an evolutionary context
It is a relative scale used to describe the reproductive success of an organism.
How do mutations arise in a population?
Through mistakes made during dna replication or through damage caused by biological, environmental, and chemical factors.
In the peppered moth example, what is the agent of selection?
It will be the environment and pollution, as the increased pollution created an environment where white moths could no longer camouflage from predators offering black moths an advantage.
Why can bacteria adapt to a changing environment faster than humans can?
This is due to their generation time which refers to the average difference in age between parent and offspring, for other species such as human this generation time can be 22-30 years, but for bacteria it can be as little as a few hours.
How did Aristotle and Lamark vie evolution?
They view evolution as a ladder to perfection with non living things at the bottom, humans at the top, and only angels and god higher than humans. They viewed that every organism was created by god the way it was meant to be and that organisms couldn’t change, die out, or create new species.
How did Darwin’s travels to Chile influence his thinking about evolution.
Prior to his travels it was believed that the way the world was created was very dependant on biblically correct information, and that all the water and land came to be the way god wanted. After Darwin experienced the earthquake in Chile he began to question this idea of no change, if the earth changed then maybe organisms would have to change to keep up with the changing environments.
Give an example of a homologous trait
Skulls of mammals
How old is Earth
4.6 billion years old
Describe the conditions of early earth
- little to no oxygen (was in a reduced state)
The process of oxidation was prevented by the removal of oxygen along with other gases and vapors. - similar environment can still be seen in deep oceans with vent communities.
what was the catalyst that pushed for a change in early earth environments?
- input of energy, specifically lightning
Describe the Urey Miller Experiment
Was an experiment ran by a student which aimed to showcase early earth environments, it had the organic primitive gases atmosphere modeled in a closed environment and showcased how when it was left to run for sometime it would begin to develop organic compounds and even important elements like amino acids.
What is chemolithotrophy
It is a way of generating energy for organisms that uses different compounds instead of the usual oxygen. Oxygen is still the final electron accept its just not the one being broken down at the beginning of the reaction.
Why is chemolithotrophy important?
It is important because it allows prokayotes to maximize their ATP production by using different electron donors than oxygen.
What are the major episodes of life
- First prokayotes
- archaean-proterozoic eons
- the great oxygenation event
- formation of eukaryotes
- Cambrian explosion
- exctinctions and mass exctinctions
Where were the first prokaryotes found?
in stromatolites which are fossilized structures from when cyanobacteria form a biofilm that can trap layers of sediments
explain the archaean-proterozoic eras
cyanobacteria were able to produce energy through photosynthesis which produced oxygen as a byproduct. This began converting the early earth reducing atmosphere into a oxidizing one. AKA rusting the earth
Describe the great oxygenation event
free oxygen began to accumulate in the atmosphere, this is supported by the presence of banded iron formations. The oxygen levels increased then plateaued and then increased again. Reasoning for the long wait until a oxygen rich environment includes:
- a long period of anoxygenic photosynthesis
- free oxygen reacted with the ocean and was not immediately released into the atmosphere
- banded iron formations mean that oxygen was reacting with iron and sulfur
- ocean reached a saturation point for oxygen
Important to remember that the number of oxygen atoms hasn’t changed, their availability has.
describe the formation of the first eukaryotic cells, and provide the evidence.
through the process of endosymbiosis.
- organelles are bound by membranes with similar composition to prokaryotes
- organelles have own circular DNA separate from the DNA in the nucleus
- mitochondrial DNA sequences similar to some bacteria, chloroplast DNA sequences similar to some cyanobacteria
- reproduction by binary fission
Describe the cambrian explosion
aka the invasion of land
- rapid appearence of many groups of organisms, development of small shell parts, modern features such as heads, mouths, eyes, and limbs begin to appear.
Why was the cambrian important
showcased genetic diversity. The increased oxygen levels allowed for eukaryotic cells to accommodate higher metabolic rates and obtain energy expensive items. There was also an evolution of grazing which reduced the algal mats and opened new niches, this began to change the ocean chemistry which began to favor the production of calcium carbonate (allows animals to have shells and the towers to form on vents)
describe the importance of extinctions and mass extinctions.
normal rate of extinction means that speciation is still occuring at a higher degree. A mass extinction occurs when the death of organisms surpasses the rate of speciation. Extinctions are important because they can clear niches. they occur periodically
What is biological diversity
it reflects the interactions between organisms and the forms that preceded them as well as the ongoing process of change
