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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
Cross this set of alleles. Aa X AA
The a is a deleterious genetic defect and in a small population the carriers of this defect will breed with each other in a probabilistically greater number.
Why do species rise from a small sample necessarily? They do not always do that. A geographically isolated species may be very large.
Regardless, look to the alleles I showed you. Probabilities are all. Say this cross in our small population.I showed these alleles existing.
Aa X Aa
This cross yields 1/4 AA, and probabilistically a small population could get out of deleterious trouble; or they could, after a time, go extinct. Lots of random events in the history of life.
Does the extent of sexual dimorphism in a species affect the rate of evolution in that species?
Perhaps, coupled with sexual selection. Take the elephant seal. The preference of females for large males to head the harems drove the evolution of larger and larger variance in the size of the males to the females and rather quickly.
No, they are random, This means that they occur in no set numerical order. So, though they can not be predicted it is certain, with the mistakes made in replication and other factors, that they will occur.
Meiosis takes place in sexual reproduction and genetic variations takes place in sexual reproduction. Genetic variations lead to evolution to new species.
Humankind has assumed responsibility for its own evolution through?
Social structure? It's culture? Genetic engineering?
The trouble with any of these answers is a basic misunderstanding of what evolution is. Evolution is the change in allele frequency over time in a population of organisms. Humans are not nearly ready to assume any responsibility for this process yet. Perhaps influence it.
The mechanism by which evolution occurs is called?
Answer
Natural selection is the mechanism put forward by Darwin as one of the two essential mechanisms for evolution, the other being random mutation (which Darwin described as inheritable variation, not knowing about genes at the time).
The modern evolutionary synthesis includes genetic mutations as the mechanism which provides variations upon which natural selection can act.
In earlier times, we might have been limited to fossil evidence. But in recent decades, some excellent genetic tests have been devised to show whether a certain genetic sequence is the result of rapid adaptation.
without variation's, all the members of a species would have the same traits.
How do organisms that are not related now appear similar?
This is called analogous traits. When two different types of organisms are in the same type of environment, usually geographically separated, they come up with very similar adaptions to their local environment.
The morphological species concept differentiates species by their physical traits, basically. The biological species concept defines a species as generally organisms that breed with others of the same species; rather a genetic isolation concept. The phylogenetic concept is based on evolutionary relationships and is the concept used by cladists.
Was Charles Darwin theory used to divide Hutu and Tutsi?
No! The theory of evolution by natural selection is an explanation of one of the more important mechanisms for evolution. It has little to nothing to do with the tribal conflicts in populations of Homo sapiens that live in the same environment.
What theory is survival of the fittest?
Be careful with this, it is usually misinterpreted as survival of fittest individuals.
Instead it is survival of fittest population via death of some individuals early.
Individuals never evolve, they are fixed genetic snapshots in the movie of life, they simply live or die. Populations evolve.
B. Allopactric speciation on island archipelagos. As the organisms move from island to island rapid speciation is observed because of variations in resource acquisition more than just variation in environment. Amplified radiation is observed. Example is finches on the Galapagos Islands. Hawaii also gives this example.
Which type of mutations contribute to evolution?
Mutation is one of the mechanism by which new alleles enter the population gene pool. Evolution is often defined as the changing of allele frequencies in population gene pools. A mutation could change the frequency of a particular allele from zero to non-zero.
What is Charles Darwin main contribution to Sociology?
His famous book, "On the Origin of Species", detailing his observations of species adaptation (especially finches of the Galapagos Islands) culminated in his theory of evolution, which has had great impact, both sociologically and scientifically, to this day.
Will natural selection act on tongue rolling in a human population?
No because theres no selective advantage
What effect does natural selection have on the frequency of a recessive lethal allele?
Perhaps not much as the recessive allele is masked in heterozygous condition. Depends on penetration and expresivity of the lethal allele, but any homozygous expression is fatal, so one can expect negative frequency selection; the freqiency is kept low by selection.
Which of the following ideas would follow from the dobzhansky-Mayr theory of speciation?
Isolated populations evolve differences gradually as they adapt to the environment
