how has extinction played a role in evolution of life on earth?

Question

organic biology

Answer 1

Back when Darwin first proposed and defended the theory of evolution via natural selection, it was generally believed that evolutionary changes happened at a constant rate. But the years progressed and the fossil record became much more well-known. Paleontologists noticed that during certain periods, the animal and plant fossils were branching out at a much faster rate. Yet in other time periods, there was very little change, or none.

This led to the formulation of the theory of Punctuated Equilibrium.

"Punctuated equilibrium (or punctuated equilibria) is a theory in evolutionary biology which states that most sexually reproducing species will show little to no evolutionary change throughout their history. When evolution does occur, it happens sporadically (by splitting) and occurs relatively quickly compared to the species' full duration on earth. For this reason, the theory is sometimes called evolution by jerks.[1] Punctuated equilibrium is commonly contrasted against the theory of phyletic gradualism (“evolution by creeps”), which hypothesizes that most evolution occurs uniformly and by the steady and gradual transformation of whole lineages (anagenesis)."

When these "spurts" of evolution occurred, a cataclysmic, mass extinction event was found to have preceded it in almost, if not every instance.

A mass extinction event would logically spur evolutionary change because such events usually spell an ecological upheaval, which would require species to adapt if they are to survive. It would also reopen ecological niches for those new species that can adapt.

Contrary to creationist claims, most genetic mutations are not harmful, but are neutral. But with the ecological changes brought about by a mass extinction event, formerly neutral charicteristics may become advantageous, or even absolutely essential.

For example, some people have webbed feet and hands. This is just one example of a mutation that causes a neutral trait to be expressed. In today's world, this is neither a hinderance, nor an advantage. However, if the world were suddenly to become flooded, a human with webbed feet and hands would have a decided advantage in finding food, shelter, and avoiding danger. This may seem kind of ridiculous as an example, but it is only an example.

In a different world, any number of traits that are neutral, or even presently harmful, could become essential. One of the requirements for evolution to take place is genetic variability. Those organisms that don't have it inevitably go the way of the dinosaurs when crisis comes.

Answer 2

Let's say a food source, such as a plant has mutated to produce a toxin that kills off the species feeding on it. Suddenly, there is a niche that needs to be filled by another species. Several new species evolve and try eating the now abundant plant. Over a period of time, one species finds a way to eat the toxic plant with impunity. Whether this be by the body being able to cope with the toxins or finding a curative such as the Macaws in South America eating clay that contains Kaolin that defeats the toxins does not matter. A new species has evolved to fill a niche.
So any animal that becomes extinct leaves a hole for natural selection to fill. Often that niche can be filled by existing species but in time, as with carnivorous dinosaurs, that niche was filled by carnivorous mammals at one level. Maybe, one day, under regressive evolution, the dinosaurs will return. I doubt that will happen, but evolution can play strange games.

Answer 3

The theory of evolution is based on the fact that organisms less fit to survive will die out and become extinct. That is how nature "selects" certain traits and allows them to evolve.

Answer 4

Extinction is a manifestation of unfitness. There have been several mass extinction events. After these events creatures that struggled suddenly flourished and creatures that flourished could not survive under the new conditions.

Answer 5

The moon is to blame for the tides, that are the technique that permits save the currents interior the oceans flowing and forestalls it from stagnating. particular species of plankton discover acquaintances and breed in elementary words for the duration of particular moon tiers - those plankton are component to the backbone of the marine environment. the sea's organic temperature alterations influence the elements kinds - in case you look on the Bering Sea section, the elements there is different nastiest interior the international because this is the position warmth water from the tropics comes up and hits the chilly waters of the Arctic. it is also why hurricanes continuously style over the sea and are frequently restricted to the equatorial and sub-tropical/warmth temperate parts of the international. there is more advantageous, yet all of it breaks right down to: the Moon is going away and undesirable issues ensue right here on earth.

Answer 6

who says it did