Presentation on theme: "A occdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is that the frist."— Presentation transcript:
A occdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is that the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. T ihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. amzanig huh?
Eevyrobdy has seen the Egnilsh rseaecrh taht sguegtss sepllnig is irrlevenat. I'd lkie to srtnalge the rseaecrehrs who did taht sutdy wtih tehir own itnseitens. The rseaecrehrs may not hvae to wrok wtih poelpe who cna't sepll, but I do!
What is Natural Selection?
What is Biological Fitness?
What is the relationship between Biological Fitness and Natural Selection?
Darwin not the first - Evolution first proposed by Lucretius, a Roman philosopher who lived nearly 2,000 years ago before the modern theory of evolution was proposed.
In 1831, because of his interest in nature, one of Darwin’s professors at Cambridge recommended him for a position as a naturalist on a voyage of HMS Beagle.
In 1809, the French scientist Jean Baptiste Lamarck (1744–1829) proposed a hypothesis for how organisms change over generations. Lamarck believed that over the lifetime of an individual, physical features increase in size because of use or reduce in size because of disuse. Lamarck correctly pointed out that change in species is linked to the “physical conditions of life,” referring to an organism’s environmental conditions.
During his voyage on the Beagle, Darwin found evidence that challenged the traditional belief that species are unchanging. Darwin found fossils of extinct armadillos. These fossilized animals closely resembled, but were not identical to, the armadillos living in the area.
Darwin suggested that the ancestors of Galápagos species migrated to the islands from South America long ago and changed after they arrived. Darwin later called such a change “descent with modification”—evolution.
I’ll bet that this applies to all species, so individuals that have physical or behavioral traits that better suit their environment are more likely to survive and will reproduce more successfully than those that do not have such traits. I’ll Call it Natural Selection
It is also my belief that organisms differ from place to place because their habitats present different challenges to, and opportunities for, survival and reproduction. Each species has evolved and has accumulated adaptations in response to its particular environment. An adaptation is a feature that has become common in a population because the feature provides a selective advantage.
In 1844, Darwin finally wrote down his ideas about evolution and natural selection in an early outline that he showed to only a few scientists he knew and trusted.
Darwin decided to publish after he received a letter and essay in June 1858 from the young English naturalist Alfred Russel Wallace (1823– 1913). Wallace’s essay described a hypothesis of evolution by natural selection! In his letter, he asked if Darwin would help him get the essay published. Darwin’s friends arranged for a summary of Darwin’s manuscript to be presented with Wallace’s paper at a public scientific meeting.
Darwin’s book On the Origin of Species by Means of Natural Selection appeared in November of Many people were deeply disturbed by certain suggestions of Darwin’s theory. However, Darwin’s arguments and evidence were very convincing, and his view that evolution occurs gained acceptance slowly from biologists around the world.
Darwin’s theory of evolution by natural selection is supported by four major points: 1. Variation exists within the genes of every population or species (the result of random mutation and translation errors). 2. In a particular environment, some individuals of a population or species are better suited to survive (as a result of variation) and have more offspring (natural selection). 3. Over time, the traits that make certain individuals of a population able to survive and reproduce tend to spread in that population. 4. There is overwhelming evidence from fossils and many other sources that living species evolved from organisms that are extinct.
How does natural variation affect populations? Explain how natural selection takes place.