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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
What is the theory of overproduction?
Overproduction is the ability of a species to produce far more offspring than can possibly survive. This leads to a 'struggle for survival'. Individuals with the most useful features (the best adaptations) also known as "survival of the fittest" will survive and leave more offspring than other individuals. Their offspring will inherit the useful variations and pass them on in their turn. This is the process of natural selection.
What kind of selection can result in speciation?
Natural selection seems to be the only selection that can drive speciation with powerful adaptive change. Sexual selection seems to stay within the species and both gene flow and genetic drift do not seem to drive speciation very well.
Describe the 4 kingdoms of eukarya?
Okk.
Basically, there are four kingdoms..
Animalia, Protista, Plantae, and Fungi.
Animalia are all "animals". Let they be reptiles, nonvertebrate chordates, chordates, mammals, homosapiens, etc.
I don't know much about protista, but they have some characteristics of plants and animals.
Plantae are plants. Their cells have a cell wall and a nucleus, somewhat similar to animal cells, but we only have cell membranes.
Fungi can be decomposers. Examples of these are mushrooms, molds, and yeasts.
What was the problem with Lamarck's theory of inheritance of traits?
It's core principle is that individual organisms can pass characteristics acquired during their lifetime to offspring; for example, a thin man works out his whole life and develops large muscles, then has a son who will also have the large muscles. However current evolutionary theory dictates that only the genetic information that determines the genetic potential of an organism is passed on to offspring - in the example, his dad was thin so he will be too - so acclimation within this genetic potential (What Lamarckian theory would suggest is passed on) is not.
Of course as with most things within evolutionary theory that's just the current thinking, recent developments in Epigenetics for example suggest Lamarckian inheritance or aspects of it may actually exist within nature to some extent.
What is the change in allele frequency following a dramatic reduction in the size of a population?
The resulting change could be anything. When one takes a few individuals out of a larger population, one basically cuts away a large part of the total population gene pool. This is known as the founder effect.
What is a mutation and why are mutations important in evolution?
The main driving force of evolution is natural which are useful by killing off those who haven't got them.
That is how we evolve, in a nutshell. hola family!!!
Mutations are the source of those variations. No variations, no evolution.
How did bacteria change early earths atmosphere?
Earth's early atmosphere was primarily composed of carbon dioxide. Early bacteria used carbon dioxide as a source of fuel and as a result produced oxygen.
What is the primary reason for hybrid sterility?
The primary reason for hybrid sterility is the incompatibility of the DNA and the difficulty in the pairing of homologous chromosomes. This does not, however, prevent successful breeding by hybrids in rare instances.
Examples of biochemical evidence of evolution?
Physiological similarities suggest the species evolved from the same ancestor.
How are evolution and extinction related?
Biodiversity is having an ecosystem with various life forms (organisms) inhabiting it. If a species goes extinct, then automatically biodiversity is decreased. This also means that other animals that may rely on this specie as a food source may also die off, resulting in a further loss of biodiversity. This will have a large ripple effect throughout the entire ecosystem.
Is macro evolution goal oriented?
Short answer: Absolutely not. Natural Selection is cleverly referred to by Richard Dawkins in the title of his famous book as The Blind Watchmaker. It has no goals. Genes have the goal of reproducing, in a sense. It is merely because they happen to have the property of self-replication, and that those that are better at it than others will eventually be more numerous that they seem driven to reproduce. Natural selection, on the other hand, has no future in mind. Every creature that ever lived was at its time, the peak of its section of the evolutionary tree. We can only consider our ancestors "less evolved" because we have the luxury of having been born after them. Humans and other apes share a common ancestor, and all modern apes are just as far evolved from our common ancestor as we are, just in a different direction.
A simple coevolution explanation here.
A population of rabbits that is running faster, on average, over time is going to affect the population of foxes that pursue the rabbits as food. Some foxes will have variations that lead to faster running and these foxes will be the ones that are reproductively successful and give rise to following generations of foxes.
How did the work of geologists support Darwin's theories about evolution?
Before Darwin proposed his Theory of Evolution, it was widely believed that the Earth was only 6,000 years old. Geologists noticed that the Earth changed gradually over time (tectonic plates shifting to create volcanoes, mountains, etc) in order for such changes to create the Earth known at that time, it would have to be building up such changes over millions of years, thus creating the idea of Earth's immense age which allowed for evolution to create the diverse species known today. This theory of gradualism (as it was called) was adapted into Darwin's theory to apply to the species and their gradual changes.
What is the theory of punctuated equillibrium?
Punctuated equilibria is also known as Punctuated equilibrium. It suggests that in most species a lot of evolutionary change takes place in short periods of time for most of their geological history, remaining in a prolonged state called stasis.
What is the difference between Lamarck and Darwin's theory of evolution?
Jean-Baptiste Lamarck proposed that organisms could pass on to their offspring traits that where acquired during their lifetime. This has come to be known as inheritance of acquired characteristics.
On the other hand Charles Darwin recognized the main mechanism for evolution: Natural Selection. Natural Selection is the process by which favorable heritable traits become more common in successive generations of a population and unfavorable heritable traits become less common, due to differential reproduction. That is: given a certain population, those individuals who are more fit to the selective pressure(s) by their habitat (in a given time and space) will leave more descendants than those less fit
In short, Lamarck thought that changes were acquired during the life of a parent organism and thentransmitted to their offspring while Darwin deducted that changes were already present in the parent organisms, and that the best adapted to that situation survived to breed, which meant that those genetic changes become common in the following generations.
Did Darwin use the word evolution?
Not in the title of his magnum opus, "The Origin of Species by means of natural selection or the preservation of favored races in the struggle for life," but yes, he used the word.
From the Online Etymology Dictionary:
1641, "to unfold, open out, expand," from L. evolvere "unroll," from ex- "out" + volvere "to roll" (see vulva). Evolution (1622), originally meant "unrolling of a book;" it first was used in the modern scientific sense 1832 by Scot. geologist Charles Lyell. Charles Darwin used the word eight times in "The Origin of Species" (1859). He preferred "descent with modification," in part because evolution already had been used in the 18c. homunculus theory of embryological development (first proposed under this name by Bonnet, 1762), in part because it carried a sense of "progress" not found in Darwin's idea. But Victorian belief in progress prevailed (along with brevity), and Herbert Spencer and other biologists popularized evolution.
They can track how long that fossil has been around by using carbon dtaing. They can also use an index fossil that is in the same rock layer. When they get the date of the fossil they can figure out what it might look like and how it ate or how it moved
Which of the following statements is accurate about evolution?
Since there are no following statements could it be........?
Evolution is the change in allele frequency over time in a population of organisms.
What must plant and animal species do in order for each species to survive?
they are able to do every kind of thing like eat food or blaah,blaah means the type of the food they eat.
How does a gene pool relate to evolution?
Mutations of DNA can cause different characteristics to what you might consider "standard" for a particular species - This is genetics and it happens all the time. If the environment in which a particular species lives changes then a certain mutation may become beneficial. The organisms with this mutation then become better adapted to live in the new conditions than the other organisms. The unmutated organisms may then begin to die out while the mutated organisms survive. These mutated organisms, over time, become the majority through breeding and the passing on of this beneficial mutation of DNA. This is evolution.
Example:
What we now know as the Horse originally had cloven feet (sort of like a camel's foot but more hand like!) which was perfectly adapted to the boggy terrain on which they lived. As the Earth began to dry out, the terrain became less and less boggy. A mutation caused some of the "Horses" to have fewer extremities (their feet were slightly more hoof-like) and they were now better adapted to the surroundings and were able to travel much faster over the drier land and escape predators. This mutation then gets passed on through breeding as the cloven footed "Horses" began to die out. Successive mutations over thousands of years resulted in the hoof and the Horse that we recognise today.
Read more: How_is_genetics_related_to_evolution
What are the 5 steps to Speciation?
There are no discrete steps to speciation. There are a number of boundary conditions that are met in most cases. Speciation is the result of any situation that leads to the genetic, behavioural and/or morphological divergence of subpopulations of the same species, which may in turn lead to a decline in interbreeding frequency. The causes for such divergence may vary. The clearest example of the principle is when two subpopulations become geographically isolated (for instance due to migration, floods or some other natural event), and diverge as a result of genetic drift. Once the two population have diverged to the degree that they would no longer produce fertile offspring together even if they were put back together again, we say that speciation has occurred.
Evaluate the significance of mutations to the process of biological evolution?
Answer 1
A.
Many mutations do produce changes in phenotype, however. Some can affect an organism’s fitness, or its ability to survive and reproduce in its environment.
Answer 2
Mutations are an important component of reproductive variation in general. Reproductive variation, the effects that causes siblings to differ both from one another as well as from the parents, is the phenomenon that makes evolution possible.
Why does a lack of transitional forms a pose problems for the evolutionary hypothesis?
A lack of transitional forms would have suggested some flaw in the fundamentals of evolutionary theory. At least, we would have expected some transitional forms to be found, if either gradualism or punctuated equilibrium was the correct model for evolution.
As it is, more than enough transitional forms have been found to date to satisfy any objective observer.
How does gene flow change allele frequencies?
Gene flow within a population distributes mutations among the individuals. Immigration and emigration transport alleles into and out of a population's gene pool, thus affecting the result of natural selection.
Summarize the main ideas in Darwins theory?
Individual organisms differ, and some of this variation is heritable
Organisms produce more offsprings than can survive, and many that do survive do not reproduce
Because more organisms are produced that can survive; they compete for limited resources
Each unique organism has different advantages and disadvantages in the struggle for existence. Individuals best suited to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring's. Other individuals die or leave fewer offsprings. This process of natural selection causes species to change over time.
Species alive today are descended with modification from ancestral species that lived in the distant past. This process, by which diverse species evolved from common ancestors, united all organisms on Earth into a single tree of life
