Final Material November 7 Why are there so many species 10 million species What is science phenomena Theory vs Hypothesis Theory Principles of Evolution Natural Selection o All come from a common ancestor explains diversity between species as well as similarities of all species on the planet all existing cells come from preexisting cells this is a hypothesis 1 The observation identification description experimental investigation and theoretical explanation of 2 Such activities restricted to a class of natural phenomena o General explanation of natural phenomena developed through extensive and reproducible observations experimental observations within that observation Hypothesis o Tentative explanation of observation o Educated guess Charles Darwin s Theory of Evolution Know Wallace came up with same hypothesis at the same time which is now referred to as a theory Sent Darwin his manuscript which Darwin stole his information and published it first to earn the credit as the first person to publish the information Alive first decade of 1800s to last decade of 1800s He travels around the world on a boat called the HMS Beagle Dad wanted him to become a doctor he flunked out sent him to religion school where he realized he wanted to He started to analyze the things he saw on his voyage and started to relate those things back to theory of become a naturalist evolution of natural selection The origins of Species by Natural Selection By Charles Darwin 1859 A lot of people refer to this as a biology bible Hypothesis by a single person came up with an explanation as to why there are so many species on a planet today and the diversity of the species on the planet today Main Points Evolution occurs in populations individuals don t evolve Population genetic structure came change in a short period of time or long period of time Final Material November 7 November 10 2014 2 main points of book by Charles Darwin Evolution occurs in populations natural selection is a mechanism for that evolution Observation 1 Potential for rapid reproduction Inference Evolution given unlimited resources living things can replicate as quickly as they can with optimal nutrients stops things from continuously dividing lack of food sub optimal conditions artificial selection These two lead to competition to survive those who survive get to reproduce Observation 2 Constant Population size over time as population increases it will become constant over time referred to as karrying capacity this is where competition will start to take place Tiger stadium Theory those who survive the tiger attack will be able to reproduce and the process will continue artificial selection Competition for survival differential reproductive success fittest individual leaves behind the most offspring and are better adapted to particular environment Variability in structures and behaviors survival of the fittest o Some variability is inherited These two lead to Natural Selection On average organisms best suited to an environment leave the most offspring Survivors pass on genes that change genetic makeup of population over time Natural Selection and Some Variability is inherited leads to evolution Evolution the genetic makeup of a population changes over time driven by natural selection o Genetic makeup change in frequency of alleles overtime o Ex make all of the people with blonde hair leave the room and the allele frequency has changed A change in the allele frequency of a population over time Genetic composition of population changes evolves o Differential survival natural selection o Selects advantageous adaptions The more time the more change Eventually become much different Not based on a belief system based on experimental results and observations Evidence Best Explained by Theory of Evolution Final Material November 7 1 Fossil record Shows no homo sapiens 50 million years ago Pakicetus 53 million years ago o oldest fossil that is still terrestrial that links back to modern whales and dolphins o The shape of the ear region in Pakicetus is highly unusual and only resembles the skulls of whales The feature is a diagnostic for cetaceans and is found in no other species 48 million years ago shows a likely descendent of pakicetus that are aquatic life adapted like hippos that are closely related to whales and dolphins thick and heavy outer coating to bones like hippos 49 million years ago motility in aquatic environment that resembles a crocodile back legs are better adapted for swimming than for walking on land and it probably swam by undulating its back vertically as otters and whales Rhodocetus 40 50 million years ago whale like though swimming style is very different Semi aquatic had large paddling hind feet to propel it through the water Strong tail which may have helped to act as a rudder Durudon 38 million years ago the pelvic bone associated with their hind limbs was no longer connected to vertebral column modern dolphin Balaena recent whale ancestor Tetrapods animals with 4 limbs have 1 bone 2 bones clump of bones then digits The loss of hind limbs from terrestrial to aquatic animals Hind limbs slow them down disadvantageous to have hind limbs November 12 2014 Final Material November 7 Pakicetus terrestrial is about 50 million years old Small changes over long periods of time have to be major in order for successful evolution Movie never watch only watch first and last 5 minutes come up with hypothesis about what happened in the middle of the movie observation would not be good because we do not have those additional pieces of information Fossil Record similarity o More parts of the movie will help to create a better hypothesis Species that exist today did not exist then and the things that existed then do not exist now Evidence Best Explained By Theory Of Evolution By Natural Selection 1 Fossil Record 2 Comparative Anatomy Analogous vs homologous structures o Homologous suggest common ancestry different change in structures in related organisms Divergent evolution different when evolution suggests change in common ancestor structure Structures 4 limbs Human cat whale bat o Homologous structures are similar because they Come from common ancestor but look different because of divergent evolution o Analogous structure DO NOT come from common ancestor convergent evolution makes them look the same Similar environmental forces select for similar structures in unrelated organisms Ability to fly some birds lost the ability to fly Birds and
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