Week 1: Rate of Evolution Flashcards
Theodosius Dobzhansky famously stated that “nothing in biology makes sense except in the light of evolution.” What did he mean by this? Give at least two specific examples of the explanatory nature of evolution.
Evolution fills in the pieces of all biology. I give answers as to why things are the way they are. Evolution is the result of natural selection; it is the ultimate purpose of natural selection.
Give a specific example of how our understanding of evolution is transforming either medicine, microbiology, agriculture, or biotechnology
Evolution of antibiotic resistant bacteria is a huge issue in medicine, this course of evolution will greatly define the future of medicine. Agriculture is a unique area where scientists are modifying evolution and shaping the future of plant species. Selective breeding of fruits of veggies without seeds controls how plants are evolving.
What is evolution? How does it occur?
Change in characteristics of a population through time and occurs as a result of natural selection.
In a biological sense, do you evolve? Explain.
No, individuals do not evolve, populations due. Changes in individuals might occur but those are mutations if the mutation is beneficial to the individual it might survive to be passed on. If that mutation eventually over a long time becomes more prevalent then the non-mutated form then evolution occurs.
Define and compare the terms microevolution and macroevolution. Are they separate processes? explain.
They are not separate processes. Microevolution is slight changes not big enough to differentiate a new species. Microevolution lead to microevolution which are larger changes over longer periods of time that will cause enough differentiation to dictate a new species.
Describe the relationship between evolution and adaptation. By what main mechanism does adaptive evolution occur?
Adaptive evolution occurs through natural election and results in evolution. Organisms adapt to environmental pressures that favor specific attributes increasing report success. Those that are adapted are more likely to survive and reproduce through natural selection ultimately resulting in evolution of the species to favor adaptives.
What is natural selection, and how does it relate to evolution?
Natural selection is the favoring or disfavoring certain traits within a population. Traits that increase reproductive success are favored while traits that work against this die off. The traits that are favored increase reproductive success and as a result are more likely to be transferred to future offspring. As this occurs over many many generations it can result in evolution of the species.
What is meant by the phrase differential reproductive success?
Some individuals are more likely to reproduce than others either because they are more successful in finding a mate or adapted to survive predation and hunger over others. No all individuals have the same reproductive success and as a result less success means less likely for their genes to be transferred to offspring.
Now describe evolution by means of natural selection in three or fewer sentences.
Evolution is characteristic changes of a species that occur over long periods of time. These changes are caused by natural selection in which specific traits result in an individual being able to reproduce more compared to others. Since most traits are heritable these traits continue for generations until they are the dominant trait resulting in evolution of the species.
Observations:
1: all species have such great potential fertility that their populations would increase exponentially if all individuals that are born reproduces successfully.
#2: populations tend to remain stable in size except for seasonal fluctuations.
#3: environmental resources are limited.
#4: individuals of a pop vary extensively in characteristics.
#5: most variation is heritable.
Inferences:
1: production of more individuals than the environment can support leads to a struggle for existence.
#2:survival in the struggle for existence is not random, depending in part on the hereditary constitution of the surviving individual .
#3: unequal ability of individuals to survive and reproduce leads to gradual changes of favorable characteristics.
When excited, do you think a panda might give you a “high five?” Explain, including the relevance of this question to evolution and adaptation.
Evolution is imperfect, pandas have a “thumb” like structure. Its is not pretty and while it works for the job it is not as good as a normal thumb.
Does evolution create new structures de novo when the need arises? Explain.
No, evolution does not create new structures. Natural selection favors structures that already exist that give individuals higher reproductive success. It only acts on traits that already exorcist, not create new ones.
There are many examples of apparent “perfection” in nature as long as you don’t investigate too deeply. Give at least two specific examples of imperfection in nature.
The flounder with eyes shifted to one side of its head, the thumb-like structure on the Panda.
What is a transitional form? Did Darwin anticipate the discovery of transitional forms? How commonplace did he envision them to be? Was he correct, either entirely or in part? Explain.
Transitional form is an organism that marks the transition from one species or group to another, it possesses traits of both species. Darwin anticipated that transitional forms would be numerous when looking at fossils. However they ended up being less prevalent then expected because the rate of evolution was not constant.
To what did Charles Darwin attribute the lack of transitional forms in his time? Was he correct, either entirely or in part? Explain.
He attributed it to incomplete fossil records, he figured with more time and fossils found the gaps would be filled in. He was partly right, more transitional forms were found over time but still much fewer than he predicted.
Does evolution act at a constant rate?
No, evolution is punctuated in which there are long periods of stasis with short periods of rapid change.
