Bases Of Evolution
  • Biological evolution, 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 central ideas of evolution are that life has a history — it has changed over time — and that different species share common ancestors.

  • A cladogram is a diagram much like a family tree showing the phylogenic tree of different species and demonstrating where they evolved from common ancestors
  • Each branch on a cladogram is referred to as a "clade" and can have two or more arms.

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Darwin1881s.jpgexternal image charles_home.png(Charles Robert Darwin.February 12th 1809 –April 19th 1882)
Charles Darwin Theory.
The modern theory of evolution was developed by Charles Darwin, an amateur English naturalist, in the 19th century.When Darwin returned from graduation in 1831 he had a letter waiting for him from Captain Robert Fitzroy. He invited Darwin to join him on the Beagle. This voyage changed his thinking about natural history like the Earth's landforms and all living organisms. He proposed that all of the millions of species of organisms present today, including humans, evolved slowly over billions of years, from a common ancestor by way of natural selection. This idea said that the individuals best adapted to their habitat passed on their traits to their offspring. Over time these advantageous qualities accumulated and transformed the individual into a species entirely different from its ancestors (e.g. birds from reptiles, whales from bears, humans from apes, etc). During Darwin's travels he saw much more diversity in the plants and animals. He was so intrigues by the fact that so many plants and animals seemed so suited no matter what environment they are in. As Darwin continued on this voyage he collected many fossils. The more he studied fossils a question was aroused. He wanted to know why so many of these species disappeared and how were they related to living species? During Darwin's voyage The Galapagos Island influenced him the most. He learned from the vice-governor of the islands that the giant tortoises varied in predictable ways from one island to another, he saw many of these tortoise on the Galapagos. He always saw many types of small, ordinary looking brown birds hopping around looking for seeds. He collected many specimens. As he examined the birds more closely he noticed that some of the birds had differently shaped beaks. As well as collecting many specimens of living species, Darwin collected many fossils. Fossils are preserved remains of ancient organisms. Some of the fossils that he had found did not look anything like living organisms but some did. Darwin noticed that some fossils of extinct animals were similar to living species. On Darwin's way back home he thought of all the patterns he'd seen on the 5 year voyage, like the Galapagos mockingbirds that turned out to belong to three separate species and the brown birds that he had thought were wrens, warblers and blackbirds were actually all species of finches. With all these discovers Darwin started to wonder if all the different Galapagos species had evolved from South America ancestors. After years of researching and filling notebook after notebook with ideas about the species and evolution, evidence shows that species are not fixed and they could change by natural variations. Natural Variations are differences among individual species.Darwin's studies had a lot to do with observation and inference's. With all his discovers with the birds and tortoises he'd take what he observed and then make inferences on why they had those specific traits.

Personally in my Biology class we had a whole section on Evolution and Darwin's voyage. During this section we researched Darwin's voyage, the places he visited and the things he saw there. Then in the correct time sequence we had to list the correct longitude and latitude. When we finished that we had to make a map of Darwin's voyage. We started in England, 1831 and followed his route until he arrived back in England, 1836. When we finished drawing the map and the places we illustrated each place with things that Darwin saw in that particular place. Then our last task was to list 10 significant observations that Darwin made, and the significance of the observations. Which is also known as observation and inferences.

Evolution Vocabulary
Decent with modification - Each living species today look differently from other species, over time.
Monophylogeny- Includes a single common ancestor and all its decedents.
Adaptions- Any inherited characteristics that increase an organisms chain of living.
Clade - Grouping of species including a single common ancestor and all descendents living and extinct.
Derived Character - Characteristics shared by members of a clade.
Artificial selection - Nature.
Natural Selection- Survival of the fittest.
Struggle for existence- Member of each species complete regularly to get food, living space, ect.
Common decent - Looking for enough back logic concludes, you can find common ancestors of all living things.
Phylogeny- Study of how living and extinct organisms are related.
Nade - Place where the ancestral lineage splits.
Malthus- Predicts that the human population will grow faster than the space and food supply.
Hutton & Lyell- Theory that geological forces have shaped.
Lamarck- Published a theory of the inheritance of an acquired traits.
Binomial Nomenclature- 2 name system (Genus & Species. Latin based)
Cladogram- Diagram showing evolutionary relationship among a group of organisms.
Fitness- The ability of an individual to survive and reproduce in a specific environment.
Survival of the fittest- Individuals that are better suited to their environment.
Vestigial organs- Resemble miniture legs, tails or other structers.
Homologous structure- Develop from the same embryonic tissue.
Evolution- Physical & mental improvements over many years of an organism to survive and reproduce.
Theory- Someone's unproven opinion. *Well tested hypothesis.*
Hox Genes- Tells what to do
Switch genes- Turns on/off.
Protein Genes- Makes everything. "Stuff Genes" Example; hair, skin, muscles. ect.


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Evolution by Natural Selection:
  • In nature, some parts of the natural world can be dangerous for its scarce water and food resources But some how, organism fight nature and survive. For generations, individuals struggle and compete to produce more off springs. Darwin wanted to know how as he called it, natural selection, works. He was trying to show that natural selection does occur and that organism do struggled to fight nature

Evidence of Evolution
Natural Selection
  • The Beaks of Darwin's Finches.Natural selection favors stouter bills in dry years, when large tough-to-crush seeds are the only food available to finches.

  • Peppered Moths and Industrial Melanism. Natural selection favors dark-colored moths in areas of heavy pollution, while light-colored moths survive better in unpolluted areas.

  • Artificial Selection. Artificial selection practiced in laboratory studies, agriculture, and domestication demonstrate that selection can produce substantial evolutionary change.

The Fossil Record
  • The Fossil Record. When fossils are arranged in the order of their age, a continual series of change is seen, new changes being added at each stage.

  • The Evolution of Horses. The record of horse evolution is particularly well-documented and instructive.

Other fields of Biology
  • The Anatomical Record. When anatomical features of living animals are examined, evidence of shared ancestry is often apparent.

  • The Molecular Record. When gene or protein sequences from organisms are arranged, species thought to be closely related based on fossil evidence are seen to be more similar than species thought to be distantly related.

  • Science does this by continuously comparing its theories objectively with evidence in the natural world. When theories no longer conform to the evidence, they are modified or rejected in favor of new theories that do conform. In other words, science constantly tries to prove its assumptions to be false and rejects implausible explanations. In this way, scientific knowledge and understanding grow over time. Religious explanations for the order of things are not science because they are based primarily on faith and do not subject themselves to be objectively falsified. Because of this fundamental difference in the approach to understanding our natural world, the U.S. Supreme Court in effect decided in 1987 that the Biblically based "creation science" is not a science and cannot be taught as such in public schools as an alternative or in addition to the mainstream evolutionary theory of the biological sciences. However, religious creation stories and the idea of "intelligent design" can be taught in philosophy, religion, or history courses. Religion and Science provide different approaches to knowledge.

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Evidence from Embryology: