What is evolution mean?

Answer 1

Evolution can be just a noun derived from the verb 'to evolve'. It means to develop, to change...

There is an evolution of everything in this sense; evolution of language, evolution of one's knowledge of a book's characters as one progresses through a book, evolution of a garden as one plants more things, evolution of this answer as I progress through writing it, evolution of the sort of questions asked on WikiAnswers...

However, the questioner most probably desires an explanation of biological evolution. This is known as the Theory of Evolution and Darwinism. It was made famous by its hypothesiser Charles Darwin. Since its hypothesis state it is now the greatest underlying theory of Biology.

It explains, along with its mechanism of Natural Selection, how organisms change over time. Gene frequencies change in populations of eukaryotes, genes are shuffled at eukaryotic meiosis and prokaryote genomes change by mutation. All these mechanisms bring about phenotypic change. Change is inevitable with the, not 100% faithful replicators, nucleic acids enclosed within the outer membranes of organisms.

Change can be selected by Natural Selection. Not all phenotypes are suited to environments and those nonsuited are eliminated by Natural Selection and this further modifies gene frequencies in populations (in eukaryotes), giving more continuous scope for evolution.

Evolution is traced via comparative genetics and genomics, comparative anatomy, comparative biochemistry and the fossil record.

According to the Theory of Evolution, life started in the oceans. Bacteria like cells first appeared and eventually branched into myriads of other forms, prokaryotic and eukaryotic. Photosynthesis evolved and multicellularity evolved. Protists radiated, as did plants and animals. Plants took over the land as simple mosses and liverworts that were gametophyte-dominant. Gradually the gametophyte was reduced to a few cells in pollen grains of angiosperms and the sporophyte generation evolved fully dominant instead.

Animals evolved from simple nerve-less and heartless organisms as sponges, eventually giving rise to both radiate and bilateral animals and among the latter, diploblastic and triploblastic lineages. On-substrate movement brought about cephalisation and as a result directionality was procured.

From wormlike creatures with notochords (the larvae of urochordates), evolved fish and from lungfish and coelocanths evolved amphibians and from amphibians evolved reptiles and from reptiles evolved mammals and dinosaurs and from dinosaurs evolved birds. Among mammals, humans evolved from apes. It is incorrect to say that humans evolved from chimpanzees. Humans and chimpanzees evolved not FROM one another but WITH one another. Both arose from a common ancestor, a Pan-Homo common ancestor.