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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
Explain Lamarck's idea about how animals change through use and disuse?
If an animal uses something they will keep that trait if not, it will die out. For instance, the giraffe's long neck was required for survival therefore they kept the trait (their ancestor's had shorter necks, which Lamarck explained was because they inherited traits gained by their parents "who had to increasingly stretch their necks for food"--this theory was incorrect). In the first snakes, which were basically lizards because they had legs, they no longer need the legs so they lost them.
Speciation caused by change in the course of a river is an example pf divergent speciation?
Allopatric speciation.
The trait, 'to live longer ', would only be selected for in individuals if it was reproductively successful. Then the alleles for living longer would be more frequently represented in the population of these animals.
1) Offspring vary slightly from their parents
2) More offspring are born then resources available
3) This competition selects for the more fit to survive and reproduce due to the traits they inherited.
4) The more fit breed and give rise to offspring that inherit some of the parental traits.
This cycle is the process of evolution, in my own words
Why did birds evolve after reptiles?
Because they can generate their own body heat - reptiles cannot and need a warm environment
How might evolution theory account for this phenomenon?
Evolutionary theory can account for the phenomenon of a new species. This is because different species can evolve from a common ancestor.
Why did Darwin disagree with lamarck?
}Firstly, Lamarck reckoned that variation depended upon environmental factors of which frequently invert and alter throughout life's course for all sorts of organisms: the analogy of giraffes neck lengths determined and supported his argument in both further, quantity and greater profitable detail, on Lamark's behalf, because when they were alive, then passed this irregular measured feature of the neck which evolved and developed over thousands of years hereditarily through generations.
As opposed to this initial objective- the Darwinian theory determined that evolution occurred through natural selection and specie categorisation. Essentially, this exemplifies the survival of the fittest, where those more adapted and aptly suited to their naturally habilitated environment survive and procreate these environmentally developed gene copies to their offspring, valuably...
Furthermore, a mutation or variation in a species may possibly allow these two opposing theoretical arguments to familiarise briefly in some points and objectives made about each theory.For instance, "if there was a pig and a giraffe in a pen with only one tree, the giraffe would survive, whereas the pig would have no means of getting food so would die".
Why Darwin could not answer all the questions regarding to his new theory?
He didn't, that's why only accepting evolution as the only option of how the heck we are here is irrational
____
Darwin was a scientist and as such understood that theories evolve as more information comes to light. He knew he didn't have all the evidence and as more came to light his theories would change accordingly. He was building on the work of others who came before him and knew later scientists would contribute their unique insights.
People think that the theory of evolution is a closed book with nothing else to contribute. And because the theory doesn't explain every single aspect of evolution, and that there are gaps in our current knowledge, that it is completely wrong. Science is alive, it changes and updates with new knowledge.
How does fossil evidence support the theory of evolution?
They tell you what lived in the past and when,
What theory proposes that species evolve during short periods of rapid change?
punctuated equilibrium
Meiosis takes place in sexual reproduction and genetic variations takes place in sexual reproduction. Genetic variations lead to evolution to new species.
How horses have changed over time?
Horses have come a long way from the three-toed, dog sized prehistoric animal they once were. Todays horses are taller and by most accounts better looking, with many different breeds to choose from.
Who is Ardi and why is she important?
Ardi is important because she is the oldest human skeleton in the whole world. She lived 4.4 million years ago.
Ardi shows upright walking with a somewhat prehensilefoot, but no "knuckle walking" like the Great Apes.
Why doesn't evolution occur through the inheritance of acquired characteristics?
Because acquired characteristics are not programmed in the DNA; only characterisitics which are genetically programmed are passed on and inherited.
Inorganic evolution is the theory of the creation of the universe, not of the species of animals found on earth (ie organic evolution). It does seem to be a point of contention among a few as how this led to complex compounds. There is no connection as no scientific evidence has shown it, yet.
What was Charles Darwin's Theory of Evolution?
Charles Darwin's theory of natural selection applies to organisms who adapt to their environment better than others and survive to pass on their traits to offspring. Due to variation in their genes, may be caused by mutation but rarely so, organisms are able to adapt to their environment. If they don't adapt well they die. If they adapt to their environment it means that they have fought for their survival and are now able to pass on their variations to their offspring and make them stronger. Often as a result a new species is formed due to the accumulated differences.
There are three types of natural selection: Directional, disruptive, and stabilizing selection. In directional selection only one extreme genotype is favored to pass on. Meaning the environment chooses one genotype to pass on. An extreme genotype for example would be either SS or ss for sickle cell, either the genotype for sickle cell is passed on or the non-sickle cell genotype is passed on. In disruptive selection, a disruption separates similar organisms causing the favoring of two extreme genotypes. For example both SS and ss are favored to pass on. In stabilizing selection only the middle genotype is favored meaning Ss which is carrier of sickle cell.
Natural selection is when the environment determines which alleles enable organisms to survive.
The theory of natural selection states that traits in a species become more or less prevalent depending on environmental pressures that select either for or against such traits.
Individuals that have traits that better suit their environment are more likely to survive.
Darwin broke down the process into 4 steps:
1. individuals that make up a population vary in their traits
2. some of these trait differences are heritable
3. in each generation, many more offspring are produced than can survive. Only some individuals survive. Of these, some will produce more offspring than others
4. Individuals with certain heritable traits are more likely to survive and reproduce.
Natural Selection occurs when individuals with certain traits produce more offspring than do individuals with certain traits produce more offspring that do individuals without those traits.
when organism adapt to the environment they will be likely to survive and produce healthy offspring.
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.
Humans have countered natural selection by medically correcting phenotypes?
Humans have countered natural selection through hybrid breeding. Even crossing a male donkey with a female horse produces a mule. Crossing certain corn strains with other corn strains to produce more grain per ear.
What is a factor is not a strong piece of evidence for evolution?
C)
Many traits of modern birds resemble the fossils of winged dinosaursC)
Many traits of modern birds resemble the fossils of winged dinosaursWhat is non random association of alleles at two or more loci?
Allele association.
Linkage disequilibrium- measure of correlation in allele frequencies between two loci.
Non-random association indicated linkage disequilibrium while random does not.
Answer 1
Evolution is not a process that can be reversed. The core principle behind evolution is that traits with a positive impact on survivability or reproduction tend to passed on to subsequent generations. Evolution itself is merely the slight alteration of a species gene pool over many generations. Perhaps you can see that the question "Is evolution reversible is something of a misnomer. Is the process by which you change something reversible In certain processes the thing that is changed can be returned to its original state, but this process also requires change. If you intended to reverse an evolutionary process the only way you could do so would be through evolution. This type of process has no non-reflexive logical inverse.
Perhaps what the question intended to ask was whether a species could "revert" back to a "less evolved" state. An example to explain this would be the reversion of humans to a more apelike genetic structure. This is certainly possible. If traits that were more apelike positively impacted the survival rate or the reproduction rate of the humans that had them than humans would begin to evolve to become more and more like our simian ancestors.
Answer 2 : There are certain examples of reversal in evolution .Most familiar trend can be seen in evolution of Dinosaurs which were of small size in Triassic period , evolved to maximum size in Jurassic period ,and again decreased in size in Cretaceous period .
Answer 3: The process of Evolution doesn't have a "direction", it doesn't favor one type of organism or trait as being "higher" than another. So in a broad sense evolution simply goes where environmental conditions dictate, there's no backward (reverse) or forward.
Could traits that were once non-adaptive reappear in a population if environmental conditions changed to make them adaptive again? Yes
Can an individual organism reacquire older traits that were not part of it's original genetic makeup? No
Do some older traits occasionally reappear in vestigial form in some individual organisms. Yes (there are instances of humans being born with a short tail etc.)
Answer 4
Evolution is basically a stochastic phenomenon. In order for evolution to "back-track", every single change in the genome that had occurred would have to be reversed in the exact reversal of the order that they occurred in. This is so extremely unlikely to ever occur that, were it observed, we would have to conclude aliens were pulling our legs.
But although evolution is not reversible, it is possible for traits to evolve a similarity with an earlier form. Consider for instance the fish-like shapes of whales: they evolved from land-dwelling mammals, which in turn can trace their ancestry back to early fish. Same shape, completely different genetics.
Answer 5
If you cloned an extinct animal, it might count as evolution going backwards. Not sure about that though, cause it's a pretty philosophical question.
