What is evolution 3A Flashcards
All species are________ ….extinction is as much a ……..
temporary,
extinctionis as much a part of nature as is the origin of species
How can we explain biodiversity?
Evolution!
Definition of Evolution for Bio 243
Change in allele frequenceies in a population over time
Definition of Evolution for Bio 243
Change in allele frequenceies in a population over time
Evolution occurs…
The time line*
after life has originated
Why are bad genes retained through evolutionary processes?
Because mutations can still occur and change allele frequencies. Natural selection cant prevent mutations from happening but they will eventually clear it.
George Curvier (1769-1832)
(2)
Found that many species have gone extinct by periodic catastrophic flooding events.
Showed large bones in USA belonged to entinct mastodons not modern elephants
Charles Lyell (1797-1875)
(2)
Landforms were not fixed but slowly changingg as a result of geological processes
Earth was much older than the accepted age as the formation of Earth’s crust took place through countless small changes occurring over vast periods of time
Jean Baptiste Lamarck (1744-1829)
(3)
- Believed that species changed overtime (transmutation)
- Proposed Lamarckism
- living things evolved in a continuously upward direction, from dead matter, through simple to more complex forms, toward human “perfection.” Species didn’t die out in extinctions
Lamarkism
Lamarckism, a theory of evolution based on the principle that physical changes in organisms during their lifetime—such as greater development of an organ or a part through increased use—could be transmitted to their offspring. Dissue would lead to atrophy and be lost/not inherited
Thomas Mathus (1766-1834)
Population increase exponentially but resources go linearly. Those better abel to comepete will survive (competition and survivial of the fittest)
Charles Darwin (4 postulates)
- Individuals within a species vary
- Some variation is inherited
- More offspring are produced than can survive and reproduce
- Survival and reproduction is not random but related to phenotype variation
not heritable trait and natural selection relationship
You can have natural selection acting on traits that are not heritable that will lead to reproductive sucess but thats not going to be something that leads to evolution because the trait can’t be inherited
Afred Russell Wallace (1823-1913)
Came up with the theory of natural selection independently of Darwin
Charles Darwin’s idea
Biological evolution is change in species over time and natural selection is just such a mechanism.
Evolution in response to natural selection is inevitable if (3)
- There is variation in a trait
- Variation is heritable
- Some variants survive and reproduce more than others
Evolution in response to natural selection is inevitable if (3)
- There is variation in a trait
- Variation is heritable
- Some variants survive and reproduce more than others
What is the driving force of biological diversity in different environments
natural selection
Endemic species
No known relative, can only be found in a specific geographical area, such as an ecological region or country.
Why species on Galapogos island were different then the South Americn mainland?
Most of the island species have had plenty of time to differemtiate from their nearest living relatives
Adaptive radiation+ex (2)
a rapid increase in the number of species with a common ancestor, characterized by great ecological and morphological diversity.
Single species will spread out through new ecosystem because there are competition, this drives some members of the species to adapt to food sources that other members cannot and this creates new species
Natural selection
When there is variation within a population and organisms, and when that variation can be inherited, the variants best suited for growth and reproduction in a given environment will contribute disproportionately to the next generation
Connection/dependance on Natural selection, ebolution and heritability
Natural selection can occur without heritability but evolution by natural selection cannot (unless phenotype is heritable, it is not going to lead to a change in the population)
