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Natural Selection
Natural selection is a function of evolution. It involves biological traits becoming more or less prominent depending on the needs and environment of a specific species.
666 Questions
Artificial and natural selection?
Artificial selection is when a human determines how an animal or plant breeds. For example: dog breeding. A breeder will put a male and female dog of the same breed together while the female is in heat in order to get them to breed. S/he chooses a male and female biased on their looks, genetics, and temperament.
Natural selection however is when nature determines how an animal breeds. For example: wolves. If the temperature drops below a level which wolves with a thinner coat cannot survive, then they will die and thicker coated wolves survive and breed, resulting in wolf pups with thicker coats.
How does natural selection lead to adaptation?
Natural selection is a filtering mechanism imposed by the environment (such as climate, terrain) and dynamics with other animals (such as predation and hunting).
Sexual selection is also a filtering system.
There are two facts that occur:
In a population, there is variation among individuals. This variation is random, caused by mutations and crossing overs, which is the mixing of genes in cells that are just about to become sperm or egg. It's why people are different from their siblings, even though they have the same two parents.
Second fact is not all animals can survive. There isn't resources for everyone, and others are food for others higher in the food chain. The environment or climate can change too.
So, within a population of the same species with different kinds of individuals, those with the best characteristics (the fastest, the strongest, the smartest for instance) will have a better chance of surviving and reproducing. They pass on the genes that give them those characteristics to the next generation. Even though the next generation will have variation due to mutation, a higher number of those genes will be in the gene pool. That's micro evolution.
Macro evolution is basically this going on for many generations. If two groups of a species separates for whatever reason, they will continue to evolve through microevolution until they can no longer reproduce with one another. When this happens, they're two different species. Then the barrier is set and they will continue to diverge into different branches of the evolutionary tree.
- Do not confuse Darwinism and evolution. Darwinism is the name loosely given to a theory, properly called Natural Selection, which attempts to explain the mechanics of evolution, which is not a theory but a set of well-observed scientific facts.
- Of course Darwinism, the theory that species of organisms develop through "natural selection" is real. The question should be "Is Darwinism correct?" And all the evidence shows that it is. Natural selection is happening right now. There is no question about it: organisms evolve through natural selection.
- The proposals in Darwin's "Origin of Species" have been examined at length by science and found to be totally supportable, and repeatedly proven by observation. Fossil records confirm species evolution in the past, microbial evolution is observed constantly in hospitals.
- Don't be misled by that word "theory." A theory is a tool used to explain the nature of facts. The fact in this case is evolution. Its existence is obvious to anyone who has ever studied the real world. Darwinism is a theory that seeks to explain the mechanics of evolution, just as Newton's Theory of Gravitation seeks to explain the mechanics of gravity.
"Rebuttal"
- Darwinism is a theory, not a fact. It is completely unproven and the social consequences of accepting such a theory need to be looked at. Not to mention that even if evolution is true, that doesn't mean that Darwinism is.
"Re-rebuttal"
Subtitled: Hey, he started it!
- Claiming that something is "theory, not fact", does nothing to address the issue.
- Claiming that a theory is "unproven" shows either a complete misapprehension of how science works, or demonstrates denial of the comprehensiveness of the evidence supporting the theory.
- Arguing "social consequences" is a blatant and undisguised appeal to consequences. Scientific theories don't become less true (or truer) just because they have less favourable (or more) consequences. In the end, only one question matters: does it match the available data, ie. is it accurate?
- Arguing that natural selection/Darwinism could still be false again does nothing to address the point that it currently does fit all the available data.
The claims of Darwinism/Evolution are that life evolves and does so by common ancestry and the driving force of that evolution is Natural Selection. It is supported by every scientist in the world (or, if it isn't, it should be, given the evidence). But never mind who supports it - it is so simple, very easy to understand. And, perhaps more importantly, there is evidence and confirmation from kaleidoscopically varied branches of science (genetics, ethology, paleontology.) There is no refutation yet and brilliant explanation. Indeed, the claims of Darwinism/Evolution are true (we conclude this because of evidence). In the terms of the question, Darwinism is real.
Most experts in the field question whether the term "Darwinism" is even appropriate. As an analogy, one might question how appropriate it is to describe an explanatory model for gravity as "Newtonism". Not just because Newton was succeeded by Einstein, but also because it's just silly.
"Darwinism", when used, is most likely to refer to Darwin's original hypotheses regarding natural selection. In effect, the question posed becomes: "Is natural selection real or not?" The answer must be, unequivocally, yes. Natural selection is observed and confirmed through so many independent lines of evidence that denying it takes place is the epitome of unreasonably.
The best way to look at evolution is to just look at the evolution of the air plane. The Wright Brothers flew the first engined powered aircraft in 1903. You may know people who were alive then. Now where has this evolved to? The "walk on the moon". How about computers? The very smallest today have evolved from rather large ones only a few years ago. These small ones have taken us to Mars. The old ones could not have done so. These are all examples of evolution and have been happening right under your nose, every day.
Remember that evolution means change over time.This is called a theory but scientists mean that these are provable facts.
Many people say that evolution is only a "theory" but this following statement is also a theory: E=MC2 This should seem familiar to all. Remember Einstein? This is his "theory". I know no one who disputes this theory.
How does natural selection explain specialization?
It doesn't per se. Speciation occurs usually when two gene pools are isolated long enough by geography or by separate selective pressures that one group becomes able to reproduce with the other with difficulty, and eventually not at all. Horses can mate with zebras and a few other animals for instance, but produce sterile offspring.
Speciation has been observed in nature many times, and forced to occur in the laboratory. Google "instances of speciation" for examples.
Natural selection is based on what 5 observations?
The theory of natural selection is based on the following assumptions about the nature of living things:
1. All organisms produce more offspring than can survive.
2. No two organisms are exactly alike.
3. Among organisms, there is a constant struggle for survival.
4. Individuals that possess favorable characteristics for their environment have a higher rate of survival and produce more offspring.
5. Favorable characteristics become more common in the species, and unfavorable characteristics are lost.
What is the third step in natural selection?
There are really no steps in natural selection - just conditions required for it to occur.
Is natural selection responsible for inherited traits?
no, inherited traits are responsible for natural selection
What is the process of Natural selection of plants?
Natural selection is the same for all organisms. There are variations in all organisms. You don't look exactly like your father or mother. Some variations are more suited to the environment they live in. Those that are more suited, survive longer and are more likely to produce more offspring. Those that are not suited wont. This means each species will change over time to become more and more suited favouring those more suited in the first place. This is the same for plants and animals. New species in plants usually begin with what is called a kline. If there are a group of plants growing up a mountain, those at the bottom will be more suited to the characteristics of where they live like warmer weather. Those at the top are more suited to their different environment. Plants next to each other will interbreed but often the same species at each end of the kline won't. If the middle of the kline disappears, perhaps by fire, we now have two new species.
Neo-Darwinism is an elaboration on Darwinism, a synthesis between modern genetics and classical Darwinism. Punctuated equilibrium is a model of Darwinism in which the rate of divergence is highly variable, as opposed to a gradualistic model of Darwinism. Panspermia is a model for the origin of life, specifically how life could have originated off-planet and then transported here. Intelligent Design is a religious view. So really, you're listing three entirely different things here (Evolution, Origin-of-Life, Religion).
Natural selection acts on variation by?
Natural selection acts on variation by picking out from a population's gene pool those that are more fit to survive. More variation leads to more natural selection. For example, currently endangered cheetas are found out to have less genetic variation than other animals. As a result, if a disatrouous event occured, there are no genes that could help the cheetas survived. Thus, natural selection prevent the cheetas from reproducing as a population and they become extinct.
What are the 4 factors of natural selection?
1. All populations have genetic variation 2. The environment presents challenges to successful reproduction 3. Individuals tend to produce more offspring than the environment can support 4. Individuals that are better able to cope with the challenges presented by their environment tend to leave more offspring than those individuals less suited to the environment do
Individuals better able to adapt to changes leave more offspring.
What are the factors which should be considered in the selection of the ideal mode of transport?
1. Past experience of the transport manager.
2. Trade magazines and journals related to transport business.
3. Trade directories and route maps.
4. specialist consultant.
Adaptation which allows for natural selection is called?
Adaptation does not allow for natural selection: natural selection causes adaptation.
What theory contends that people have a natural capacity to make decisions about their lives?
humanistic
What factors must be considered in the selection of electrodes?
factors f0r selecting electrode.......a.base metal strength properties b.base metal composition c.welding position d.welding current e.joint design and fit-up f.thickness and shape of base metal and g.service c0nditions and or specification
