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In short, genetic mutations.
Most random genetic mutations have no bearing on the organism at all, but sometimes they do cause changes.
For example: A certain species of beetle may only be green. Its species is preyed upon by a particular bird that only likes green beetles. Then, one day a beetle is born with a genetic mutation that shifts its color from green to brown (this is the random mutation part). The bird doesn't eat the brown beetles. Therefore, the brown beetle is able to reproduce almost indefinitely, and then its offspring reproduce indefinitely, likely passing on the gene for the brown color. Eventually, the whole population of beetles shifts from green to brown and the birds find something else to eat (this is the natural selection part).
However, it works in the opposite way too. A perfect example would be a deer that is born albino. It will stick out like a sore thumb and be eaten quite quickly, leaving it no time to reproduce.
Evolution works in this way because natural selection itself is not random, though mutations are. An organism is constantly trying to adapt to its environment in a better way through natural selection, but its environment is always changing as well.
As for what causes the mutation, a number of things can occur (Its first quite important to know that DNA codes for amino acids, which are the building blocks of proteins, and the structure of the protein determines how it folds, and the fold determines the function). Sometimes, a base (that would be adenine, thymine, cytosine, or guanine) is simply left out or doubled, which causes a frame-shift in how the DNA code is read. This will subsequently change EVERY amino acid and make a completely different protein, which is sometimes functional and sometimes not. Furthermore, sometimes an entire gene is replicated, or even an entire chromosome. Sometimes, these replications don't do anything until another type of mutation effects on the genes/chromosomes and it creates a functional protein. For an example of this, Google "nylonase."
Its actually quite more complicated than this, but its impossible to answer it in full depth here. There are a lot of great videos on YouTube by user cdk007 that explain it a bit better, and of course there is always Wikipedia.
What else can I help you with?
Why are there so much variation with a species?
Variation within a species is due to genetic diversity, which arises from random mutations, recombination during reproduction, and gene flow from other populations. This variation provides the raw material for natural selection and enables species to adapt to changing environments.
What constantly provides new variation for natural selection to act upon in a sexually reproducing popularion?
Firstly, mutation. In a sexually reproducing population recombination ( independent orientation of chromosomes and crossing over in meiosis and random fertilization ) is also a source of variation in populations.
How is change by natural selection different from change due to a mutation?
Change by natural selection occurs when certain traits provide a survival or reproductive advantage in a given environment, leading to those traits becoming more common in a population over generations. In contrast, a mutation is a random change in an organism's DNA that can introduce new traits. While mutations are the source of genetic variation, natural selection acts on that variation, favoring beneficial mutations and weeding out harmful ones. Thus, mutations are the raw material for evolution, while natural selection is the mechanism that drives adaptive change.
Variation in a new generation is he result of?
Variation in a new generation is the result of a combination of genetic factors inherited from the parents, as well as random mutations that occur during the process of DNA replication. These variations contribute to the diversity seen within a population and are essential for natural selection and evolution.
How natural selection takes place?
simply put, only the strong will survive
What are the Elements of the theory natural selection?
Replication random variation Non-random survival
Why would natural selection not occur in population?
It has not reached carrying Capacity
Which is not part of darwins theory of natuarl selsction?
The idea that evolution is a directed process with a predetermined goal or purpose is not part of Darwin's theory of natural selection. Instead, Darwin proposed that evolution occurs through random variation and selection based on the fitness of individuals in a given environment.
Why is natural selection random?
No. Natural selection is the non-random survival of randomly varying replicators. The random variation part could be thought of as mutation and recombination that the non-randompart, natural selection, works with.
All of these terms EXCEPT contribute to natural selection?
Genetic drift, as it is a random process that does not necessarily contribute to the differential survival and reproduction of individuals. Variation, heritability, and differential reproductive success are essential components of natural selection.
Why would natural selection not occur without genetic variations on species?
Without variation it would not be selecting, just random death of identical units.
How does natural selection affect variation?
Variation naturally occurs in populations as new traits arise from random mutations. However, through natural selection only those traits that are beneficial to the organism are passed on to the next generation. Any harmful mutations are naturally weeded out.
What are 3 basic components to today's theory of evolution?
Three basic components of today's theory of evolution are genetic variation within a population, natural selection acting on this variation, and the inheritance of traits that confer a survival or reproductive advantage.
Is random selection of prey essential in any model of natural selection?
No, many forms of natural selection have no connection to predation.
What are the 2 things necessary for evolution to occur?
Answer 1Two broad processes that make evolution possible are 1 : directional forces including mutation , migration and selection and 2: nondirectional forces that include random genetic drift , bottleneck effect , founders effect ,and chance variations .Answer 2Evolution is most commonly described as a combination of reproductive variation and differential reproductive success.Reproductive variation in itself is a "non-directional" phenomenon, that produces mostly random variations. Differential reproductive success (or: natural selection) is a "directional" phenomenon, that basically acts as a mechanism limiting the set of "directions" produced by random variation.
Why are there so much variation with a species?
Variation within a species is due to genetic diversity, which arises from random mutations, recombination during reproduction, and gene flow from other populations. This variation provides the raw material for natural selection and enables species to adapt to changing environments.
Evolution suggests that the life we see today developed by chance.?
Evolution is not simply a result of chance, but rather a process driven by natural selection and genetic variation over time. It is a gradual and non-random change in species that leads to better adaptability to their environment. Random mutations may occur, but it is natural selection that determines which traits are advantageous and will be passed on to future generations.
