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EVOLUTION

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EVOLUTION. Evolution. - PowerPoint PPT Presentation
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Page 1: EVOLUTION
Page 2: EVOLUTION

Evolution• The meaning of evolution is almost always known as: “the gradual

process in which something changes into a different and usually more complex or better form” ,but deeper in biology, it is define as: “Change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species.”

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Proof of Evolution• There are many records that proofs the evolution theory. Some

examples are:

• 1. The universal genetic code. • 2. The fossil record. • 3. Genetic commonalities. • 4. Common traits in embryos. • 5. Bacterial resistance to antibiotics.

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Anatomy• Individual organisms contain, within their

bodies, abundant evidence of their histories. The existence of these features is best explained by evolution.

• Example: People (and apes) have chests that are broader than they are deep, with the shoulder blades flat in back. This is because we, like apes, are descended from an ancestor who was able to suspend itself using the upper limbs.

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Paleontology. • It is the scientific study of prehistoric life. It includes the study of

fossils to determine organisms evolution and interaction with each other and their environments.

• It has three main elements: description of the phenomena; developing a general theory abaut the causes of various types of change; and applying those theories to specific fats.

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-Subdivisions • Vertebarte paleontology, invertebrate paleontology, paleobotany,

polynology, micropaleontology, paleoecology, paleoclimate.

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-Paleontology proofs. • the results of stratigraphic analysis document the evolution of organisms

from a common ancestor, showing that the individual organisms do not appear in the paleontological record at random, but rather in the order that corresponds to their mutual similarity and thus assumed relatedness. On the basis of the similarity of the members of the main taxa of vertebrates – fish, amphibians, reptiles and mammals – it can be concluded that they were most probably formed one from another in this order. Theoretically, it would also be possible that they would be formed from one another in the opposite order, i.e. that first mammals would be formed, from them reptiles, then amphibians and finally fish.

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•However, this possibility can be refuted by comparison of fish and mammals with invertebrate fauna, which certainly have far more common traits with fish than with mammals. Perusal of the paleontological record reveals that, of these groups, fish actually did appear first on the Earth, followed by amphibians, reptiles and finally mammals. The same analysis can be performed in any monophyletic taxon, i.e. within a group of organisms for which it can be assumed, on the basis of independent data, that they evolved from a common ancestor. In every case, we obtain results that are in full agreement with the predictions made on the basis of the theory of evolution. This indicates that the individual groups of organisms emerged gradually over time through divergence from a common ancestor .

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FOSSIL:• Fossils show us the existence of species which lived in the past, and which

have now become extinct. The fossil record is not complete, but we can still compare the anatómical features of fossils with those of current species. In many cases, it´s clear that they share the same structural pattern.

• ADITIONAL INFORMATION:• In the 17th century , Nicholas Steno shook the world of science, nothing the

similarity between shark teeth and the rocks commonly known as the( tongue stones ) this was our fist undestanding that fossils were a record of past life.

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Bio-geography. • It is the study of the distribution of species and ecosystems in

geographic space and through geological time. Organisms and biological communities veny in a highly regular fashion along geographic gradients of latitude, elevation isolation and habitat area.

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- Bio-geographycal proofs. • Many of Charles Darwin's most important discoveries occurred on

remote islands, such as the Galapagos. In these remote locations, Darwin noticed that there were unique species, and that these species were not found anywhere else. More importantly, these animals were not found in similar climate zones elsewhere on Earth. It's from this insight that much of evolution's most important biogeographical proof emanates. Darwin sought to answer the question, "Why do animals on distant and isolated landmasses appear related, but distinct?" Evolution was his answer.

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Biochemical

• Consist of comparing certain molecules that occur in all living things, so that these molecules will be more like the smaller evolutionary differences between their possessors.

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Embryology • In all species are found similar

ancestral characteristics in embryonic development, and disappear during the process. Because of this, Ernst Haeckel enunciated in 1866 the recapitulation theory summarized in: ontogeny is a recapitulation of phylogeny, ie ontogeny or individual development, is a compendium of the phylogeny or historical development of the species.

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THE ORIGIN OF SPECIES• During history, there were many scientifics which made theories

about how the species appeared, how they adapted and how they survived to the constant changes of the world.

• The most known theories are:• Creationist theory• Jean-Baptiste Lamarck’s theory• Charles Darwin’s theory: “On the origin of species”• Others

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Creationist theory or Creationism• Creationism is the belief that the Universe and living organisms

originate "from specific acts of divine creation.• For young Earth creationists, this includes a literalistic reading of the

Book of Genesis and the rejection of evolution.

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Lamarck’s theory or Lamarckian inheritance• It is the idea that an organism can pass on characteristics that it

acquired during its lifetime to its offspring (also known as heritability of acquired characteristics or soft inheritance)

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Charles Robert Darwin’s Theory• He established that all species of life have descended over time from

common ancestors, and in a joint publication with Alfred Russel Wallace introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.

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Summary of Darwin's theory• Every species is fertile enough that if all offspring survived to reproduce the

population would grow (fact).• Despite periodic fluctuations, populations remain roughly the same size (fact).• Resources such as food are limited and are relatively stable over time (fact).• A struggle for survival ensues (inference).• Individuals in a population vary significantly from one another (fact).• Much of this variation is inheritable (fact).• Individuals less suited to the environment are less likely to survive and less likely

to reproduce; individuals more suited to the environment are more likely to survive and more likely to reproduce and leave their inheritable traits to future generations, which produces the process of natural selection (inference).

• This slowly effected process results in populations changing to adapt to their environments, and ultimately, these variations accumulate over time to form new species (inference).

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REPRODUCTIVE ISOLATION

-Inviability of the xygote: fertilisation occurs but the egg doesn´t beging or end its development. A sheep can fertilise a goat but the embryo will not develop

completely and will be before birth.- Sterility of the descendants of the first or later generations in these cases, the development is complete, but the adult descendants are sterile. In capacity a descendant of a tiger and a lion has been obtained , but only the females are

fertilise.CAUSE OF REPRODUCTIVE ISOLATION:- One of the cause for a separation between populations in the presence of a geographical barrier between them.

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Questions:• What is a fossil ?• What is bio-geography?, How does bio-geography proofs follow the

theory of evolution?• What is paleontology?,Name 3 types of paleontology subdivision.

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- What type of proof of evolution corresponds the following sentence?: "Ontogeny is a brief recapitulation of phylogeny"

      * biochemical        *paleontological        *biogeographic        *anatomical        *embryological

- Name and define the most known theories of evolution and who was or were the person which created each one.

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Project and PowerPoint Presentation made by:

• Ihone Garcia Moya• Maria Rubio• Marina Diaz• Cristian Calzadilla


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