Anchor Summary
The theory of evolution states that every species on Earth today descended from species that had already existed previously. Meaning that any two species are related due to the fact that they share a common ancestor species. When organisms die they leave behind evidence of their existence in the form of fossils. Fossil evidence tells us that fixed existed before vertebrates and dinosaurs existed before the first birds. Paleontologist identified transitional fossils or intermediate forms between older species and their more modern descendants. Scientist can restrict evolutionary history by determining the number of differences in a DNA sequence for pairs of species. In natural selection individuals are more likely to survive and reproduce, leading the changes in the alleles of a population or species. For example, peppered moths were mostly found in the United Kingdom where there were grey with black speckles. The coloring helped to camouflage he moths again the lichen-covered trees of the moths environment, helping to avoid their predators. But coal burning factories ended up being built close by the U.K darkening the barks on the trees killing the lichens. Turning the peppered moths black. The black moth phenotype is an example of adaptation helping an individual to survive and reproduce in its environment. When the environment changes , new selection pressure acted on some of the moth populations leading to changes in allele frequencies. The simplest way for an allele's frequency to change is through migration. If the population is small, the effect of even a small number of migrating individuals can be great. Evolution does not occur only to change existing species. Sometimes, the separation of populations is due to geographical isolation.
e effect of even a small number of migrating individuals can be great. Evolution does not occur only to change existing species. Sometimes, the separation of populations is due to geographical isolation.
The theory of evolution states that every species on Earth today descended from species that had already existed previously. Meaning that any two species are related due to the fact that they share a common ancestor species. When organisms die they leave behind evidence of their existence in the form of fossils. Fossil evidence tells us that fixed existed before vertebrates and dinosaurs existed before the first birds. Paleontologist identified transitional fossils or intermediate forms between older species and their more modern descendants. Scientist can restrict evolutionary history by determining the number of differences in a DNA sequence for pairs of species. In natural selection individuals are more likely to survive and reproduce, leading the changes in the alleles of a population or species. For example, peppered moths were mostly found in the United Kingdom where there were grey with black speckles. The coloring helped to camouflage he moths again the lichen-covered trees of the moths environment, helping to avoid their predators. But coal burning factories ended up being built close by the U.K darkening the barks on the trees killing the lichens. Turning the peppered moths black. The black moth phenotype is an example of adaptation helping an individual to survive and reproduce in its environment. When the environment changes , new selection pressure acted on some of the moth populations leading to changes in allele frequencies. The simplest way for an allele's frequency to change is through migration. If the population is small, the effect of even a small number of migrating individuals can be great. Evolution does not occur only to change existing species. Sometimes, the separation of populations is due to geographical isolation.
e effect of even a small number of migrating individuals can be great. Evolution does not occur only to change existing species. Sometimes, the separation of populations is due to geographical isolation.
Objectives
Explain how natural selection can impact allele frequencies of a population. Describe the factors that can contribute to the development of new species Explain how genetic mutations may result in genotypic and phenotypic variations within a population. |
Essential Questions
What is evolution? How does the evidence of geology, and fossils support the theory of evolution? |
Vocabulary
Fossils- are remains or traces of organisms that once lived and have been preserved.
Homologous structures- share an evolutionary relationship.
Analogous structures- perform similar functions
Vestigial structure- has lost its original function, but suggests that the species descended from an ancestor with the fully intact, functional structure.
Mutation- is a change in a DNA sequence
Mechanisms of Evolution- is the change in allele frequencies over time that results in new species developing from existing species
Natural Selection- is the process in which alleles for traits that give an advantage in survival and reproduction are more likely to be passed onto offspring. These alleles increase in the population.
Allele frequency-refers to how commonly an allele occurs in a population. An allele with a higher frequency is more common than one with a lower frequency Population- of organisms inhabits an area and shares a gene pool
Genetic drift- is a change in allele frequencies that occurs due to chance events rather than difference in fitness
Migration- the movement of individuals into and out of a population, can change the
population’s allele frequencies.
Founder effect- is a decrease in gene variation in a population.
Speciation- refers to the formation of new species and occurs when one population is isolated from another
Species- is defined as a group of similar organisms that are capable of mating and producing fertile offspring Isolating
Mechanism- is a physical or behavioral trait that prevents a member of one species from mating with a member of a different species and producing fertile offspring
Fossils- are remains or traces of organisms that once lived and have been preserved.
Homologous structures- share an evolutionary relationship.
Analogous structures- perform similar functions
Vestigial structure- has lost its original function, but suggests that the species descended from an ancestor with the fully intact, functional structure.
Mutation- is a change in a DNA sequence
Mechanisms of Evolution- is the change in allele frequencies over time that results in new species developing from existing species
Natural Selection- is the process in which alleles for traits that give an advantage in survival and reproduction are more likely to be passed onto offspring. These alleles increase in the population.
Allele frequency-refers to how commonly an allele occurs in a population. An allele with a higher frequency is more common than one with a lower frequency Population- of organisms inhabits an area and shares a gene pool
Genetic drift- is a change in allele frequencies that occurs due to chance events rather than difference in fitness
Migration- the movement of individuals into and out of a population, can change the
population’s allele frequencies.
Founder effect- is a decrease in gene variation in a population.
Speciation- refers to the formation of new species and occurs when one population is isolated from another
Species- is defined as a group of similar organisms that are capable of mating and producing fertile offspring Isolating
Mechanism- is a physical or behavioral trait that prevents a member of one species from mating with a member of a different species and producing fertile offspring