To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

Outline of evolution

From Wikipedia, the free encyclopedia

The following outline is provided as an overview of and topical guide to evolution:

A diagram showing the relationships among various groups of organisms

In biology, evolution is change in the heritable characteristics of biological organisms over generations due to natural selection, mutation, gene flow, and genetic drift. Also known as descent with modification. Over time these evolutionary processes lead to formation of new species (speciation), changes within lineages (anagenesis), and loss of species (extinction). "Evolution" is also another name for evolutionary biology, the subfield of biology concerned with studying evolutionary processes that produced the diversity of life on Earth.

YouTube Encyclopedic

  • 1/5
    Views:
    1 090 669
    3 496
    181 792
    75 065
    560
  • Five fingers of evolution - Paul Andersen
  • Cultural evolution: broad outline of prehistoric cultures (General introduction to anthropology)
  • How Are Organisms Classified? | Evolution | Biology | FuseSchool
  • CARTA: Domestication: Transformation of Wolf to Dog; Fox Domestication; Craniofacial Feminization
  • The Outline of Science, Vol 1 (Solo) by J. Arthur THOMSON read by Mark F. Smith | Full Audio Book

Transcription

(Music) The Five Fingers of Evolution. A thorough understanding of biology requires a thorough understanding of the process of evolution. Most people are familiar with the process of natural selection. However, this is just one of five processes that can result in evolution. Before we discuss all five of these processes, we should define evolution. Evolution is simply change in the gene pool over time. But what is a gene pool? And for that matter, what is a gene? Before spending any more time on genetics, let us begin with a story. Imagine that a boat capsizes, and 10 survivors swim to shore on a deserted island. They are never rescued, and they form a new population that exists for thousands of years. Strangely enough, five of the survivors have red hair. Red hair is created when a person inherits two copies of the red gene from their parents. If you only have one copy of the gene, you won't have red hair. To make this easier, we will assume that the five non-redheads are not carriers of the gene. The initial frequency of the red hair gene is therefore 50 percent, or 10 of 20 total genes. These genes are the gene pool. The 20 different genes are like cards in a deck that keep getting reshuffled with each new generation. Sex is simply a reshuffling of the genetic deck. The cards are reshuffled and passed to the next generation; the deck remains the same, 50 percent red. The genes are reshuffled and passed to the next generation; the gene pool remains the same, 50 percent red. Even though the population may grow in size over time, the frequency should stay at about 50 percent. If this frequency ever varies, then evolution has occurred. Evolution is simply change in the gene pool over time. Think about it in terms of the cards. If the frequency of the cards in the deck ever changes, evolution has occurred. There are five processes that can cause the frequency to change. To remember these processes, we will use the fingers on your hands, starting from the little finger and moving to the thumb. The little finger should remind you that the population can shrink. If the population shrinks, then chance can take over. For example, if only four individuals survive an epidemic, then their genes will represent the new gene pool. The next finger is the ring finger. This finger should remind you of mating, because a ring represents a couple. If individuals choose a mate based on their appearance or location, the frequency may change. If redheaded individuals only mate with redheaded individuals, they could eventually form a new population. If no one ever mates with redheaded individuals, these genes could decrease. The next finger is the middle finger. The M in the middle finger should remind you of the M in the word "mutation." If a new gene is added through mutation, it can affect the frequency. Imagine a gene mutation creates a new color of hair. This would obviously change the frequency in the gene pool. The pointer finger should remind you of movement. If new individuals flow into an area, or immigrate, the frequency will change. If individuals flow out of an area, or emigrate, then the frequency will change. In science, we refer to this movement as gene flow. All four of the processes represented by our fingers can cause evolution. Small population size, non-random mating, mutations and gene flow. However, none of them lead to adaptation. Natural selection is the only process that creates organisms better adapted to their local environment. I use the thumb to remember this process. Nature votes thumbs up for adaptations that will do well in their environment, and thumbs down to adaptations that will do poorly. The genes for individuals that are not adapted for their environment will gradually be replaced by those that are better adapted. Red hair is an example of one of these adaptations. Red hair is an advantage in the northern climates, because the fair skin allowed ancestors to absorb more light and synthesize more vitamin D. Thumbs up! However, this was a disadvantage in the more southern climates, where increased UV radiation led to cancer and decreased fertility. Thumbs down! Even the thumb itself is an adaptation formed through the process of natural selection. The evolution that we have described is referred to as microevolution, because it refers to a small change. However, this form of evolution may eventually lead to macroevolution, or speciation. Every organism on the planet shares ancestry with a single common ancestor. All living organisms on the planet are connected back in time through the process of evolution. Take a look at your own hand. It's an engineering masterpiece that was created by the five processes I just described, over millions and millions of years. Can you recall the five main causes of evolution from memory? If you can't, hit rewind and watch that part again. But if you can, give yourself or your neighbor a big five-fingered high five.

Fundamentals about evolution


Introduction

Basic principles

  • Macroevolution – Evolution on a scale at or above the level of species
    • Speciation – Evolutionary process by which populations evolve to become distinct species
    • Despeciation – Loss of a species of animal due to its combining with another species
    • Anagenesis – Gradual evolutionary change in a species without splitting
    • Extinction – Termination of a taxon by the death of its last member
  • Microevolution – Change in allele frequencies that occurs over time within a population
    • Artificial selection – Breeding used to develop desired characteristics
    • Natural selection – Mechanism of evolution by differential survival and reproduction of individuals
      • Sexual selection – Mode of natural selection involving the choosing of and competition for mates
    • Mutation – Alteration in the nucleotide sequence of a genome
    • Gene flow – Transfer of genetic variation from one population to another
    • Genetic drift – Concept in genetics

Subfields

History

Evolutionary theory and modelling

See also Basic principles (above)

Population genetics

Evolutionary phenomena

Modelling

Taxonomy, systematics, and phylogeny

Fundamentals

Basic concepts of phylogenetics

  • Phylogenetic tree – Branching diagram of evolutionary relationships between organisms
  • Phylogenetic network – Graph used to visualize evolutionary relationships, including reticulation events
  • Long branch attraction – Systematic error in phylogenetics
  • Clade – Group of a common ancestor and all descendants
  • Grade – Non-monophyletic grouping of organisms united by morphological or physiological characteristics
  • Ghost lineage – Phylogenetic lineage that is inferred to exist but has no fossil record

Inference methods

Current topics

Group Traits

  • Symplesiomorphy – An ancestral character or trait state shared by two or more taxa
  • Apomorphy – Two concepts on heritable traits
  • Synapomorphy – Two concepts on heritable traits
  • Autapomorphy – Distinctive feature, known as a derived trait, that is unique to a given taxon

Group Types

  • Monophyly – Property of a group of including all taxa descendant from a common ancestral species
  • Paraphyly – Type of taxonomic group
  • Polyphyly – Property of a group not united by common ancestry

Evolution of biodiversity

Origin and evolutionary history of life

Evolution of organisms

Evolution of tetrapods

Evolution of other animals

Evolution of plants

Evolution of other taxa

Evolution of cells, organs, and systems

Evolution of molecules and genes

Evolution of behaviour

Evolution of other processes

Applications in other disciplines

Evolutionary issues

Controversy about evolution

Religious and philosophical views of evolution

Influence of evolutionary theory

Publications and organizations concerning evolution

Books

Journals

Organizations

Evolution scholars and researchers

Prominent evolutionary biologists

See also

External links

General information
Experiments concerning the process of biological evolution
Online lectures
This page was last edited on 28 February 2024, at 11:05
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.