Evolution

EVOLUTION http://www.youtube.com... Firstly I'd like the reader to ponder these statistics: 99% of all species (kinds) of creatures that have ever lived on planet earth are now extinct, maybe we too will join them if we don't maintain our biological fitness. Dinosaurs ruled the Earth for over 100 million years, humans have existed for less than 2 million years. If The Existence of the Universe until now was compressed into a single year, humans have only existed for less than the final 60 seconds. Source: How Do We Define and Explain Evolution? “The definitionBiological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life. The explanationBiological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance. The central idea of biological evolution is that all life on Earth shares a common ancestor, just as you and your cousins share a common grandmother. Through the process of descent with modification, the common ancestor of life on Earth gave rise to the fantastic diversity that we see documented in the fossil record and around us today. Evolution means that we're all distant cousins: humans and oak trees, hummingbirds and whales.” [Source: #1] Evolution encompasses many sub concepts and Theories: I will cover some of these in this statement: Though Con has already demonstrated a misconception of “Natural Selection” so I will not go into detail on this at first. As to understand Natural Selection, there are a few concepts that need to be covered, concepts that Darwin utilised to build his concept of Natural Selection on in the first place. Without Knowledge of these, Natural Selection is easily misunderstood. This is where I believe Con has gone wrong. Going straight for Natural Selection without properly understanding the underlying concepts behind it. A Very Brief History Of Evolution: Patterns: Humans eventually started to notice that patterns concerning living creatures, geological formations and finally Fossils seemed to have noticeable patterns. Some forefathers of Evolution, such as Leonardo da Vinci, noticed that fossils existed in distinct layers and started questioning the religious stories of a global flood and Leonardo thus considered the book of Genesis with it's great flood as wrong. He realised that if such a flood occurred then these fossils would not be in distinct layers but jumbled. So remember this next time you view the Mona Lisa or his “Last Supper” that Leonardo had already dismissed the Global Flood as mythical. He can be considered as the great grandfather of Evolution. Selection by Humans or Artificial Selection: Humans were developing specialised crops and domestic animals by deliberately selecting only those that traits that were useful or plants that had better qualities or disease resistance. This Unnatural Selection was in full swing prior to the birth of Charles Darwin. By only selecting a specific plant or animals, due to some desired characteristic (size, color, length of tail, production of milk, etc..) the genetics of these selected species became dominant and thus an entire species of this creature/plant was artificially created by humans. Darwin noted this Artificial selection process, and from it, realized that Nature performs its very own Selection Process, though Nature does not have any desires, it just provides the influences or Environment, that performs the selection and if the species cannot cope with the changes in their environment (poor fitness) they become Extinct. SPECIES: Definition “noun, singular or plural: species (taxonomy) (1) The lowest taxonomic rank, and the most basic unit or category of biological classification. An individual belonging to a group of organisms (or the entire group itself) having common characteristics and (usually) are capable of mating with one another to produce fertile offspring. Failing that (for example the Liger) It has to be ecologically and recognisably the same.” [Source: #3 ] 1: Fitness: This is the Capability Of or Capacity For Both Survival and Reproducing: Individual Fitness depends on several factors, some of these are: Reproductive Health. Availability of reproductive partners Attractiveness to reproductive partners Ability to compete against rivals in accessing reproductive partners. Environmental Factors affecting Population and Reproduction Diseases, Predators, Climate and Changes to that environment, such as Global Warming. Fitness of the Individual analogies greatly simplified as realistic fitness formulas are beyond the scope of this debate: Fitness of a Species/Genotype/Phenotype depends on the mortality rate within that environment from climate influences (storms, etc.) predator and disease mortality rates. If the mortality rate is greater than the reproduction rate, the species has zero fitness and the species is doomed to certain Extinction. This is why most species try to reproduce to the maximum of their capabilities, so they can defeat the high mortality rate for that environment. Essentially: If it cannot breed or reproduce with the previous form it is a new species. Yet all the Galapagos Islands is where Darwin found many different varieties of finches, yet, some of these finches cannot breed or reproduce with any other finches on these islands. This means that since they cannot reproduce with another of a similar type, they have become a different Species of finch. Even though they are still finches. Darwin noticed this and came up with the concept from these observations, that if Humans can Artificially Select creatures for specific features and traits, why can't nature do it as well. Thus the term Natural Selection. Instead of humans artificially selecting characteristics, nature ( the environment) is making the selection. Example: The famous Peppered Moths. http://www.mothscount.org... These moths were lucky that they had such Variation: Had there only been light moths, they would have become extinct in that region as their fitness was very poor. Which brings up the final subject for this introduction: “GENETIC VARIATION: Without genetic variation, some of the basic mechanisms of evolutionary change cannot operate. There are three primary sources of genetic variation, which we will learn more about: Mutations: are changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. Gene flow: is any movement of genes from one population to another and is an important source of genetic variation. Sex: can introduce new gene combinations into a population. This genetic shuffling is another important source of genetic variation. [Source: #4]“ This is the reason why Populations need to be large, as a larger a population, the more variations will exist within that population and thus the greater chance that one of those variations will have a characteristic that assists the fitness of the species. This is well known in searching for a disease resistant variety of plant. A researcher may plant millions of seeds while exposing the young seedlings to the particular disease, eventually, a seedling may survive the disease and now exists a disease resistant plant to breed more disease resistant seeds and plants from. This is artificial selection which Darwin wrote about, but in nature similarities occur. This is why insects that produce millions of offspring, such as mosquitoes will eventually become resistant to a pesticide, because eventually one of the millions of genetic variations will survive the pesticide and thus maintain fitness and reproduce thousands more pesticide resistant mosquitoes. Humans are the predator in this scenario of Natural Selection and eventually the rebounding fitness of the mosquitoes will defeat human attempts to eradicate them. Meaning humans will need to find another weapon. This demonstrates the power of Natural Selection, especially with creatures that produce such massive numbers of offspring and thus such a huge variation of traits in each generation. This why having a massive population of offspring not only helps with biological fitness for a species, but it provides a large variation from which useful characteristics may become available for assisting the survival fitness of the species when that fitness is threatened by changes in the environment, such as introduction of new predators by humans, pesticides and antibiotics (bacteria uses the same Natural Selection process for developing resistance). Another View Of Natural Selection: “Several hundred million years ago, there were no vertebrate animals on land. The only vertebrate species in the world were fish, all of which lived underwater. Competition for foodwas intense. Some species of fish that lived near the coast developed a strange mutation: the ability to push themselves along in the mud and sand on the shore with their fins. This gave them access to food sources that no other fish could reach. The advantage gave them greater reproductive success, so the mutation was passed along. This is what we call natural selection. “ [Source: #2] A Short Video on Evolution: http://www.youtube.com... #1: http://evolution.berkeley.edu... #2: http://science.howstuffworks.com... #3: http://www.biology-online.org... #4: http://evolution.berkeley.edu...