What is Evolution The Process of Evolution Biological

What is Evolution? – The Process of Evolution § Biological populations § Groups of individuals of the same species that are subdivided from other populations by geography § Biological evolution § Change in the characteristics of a population of organisms that occurs of over the course of generations. § Evolutionary changes are inherited via genes. © 2013 Pearson Education, Inc.

What is Evolution? – The Process of Evolution § Pesticide resistant lice are an example of biological evolution. © 2013 Pearson Education, Inc.

What is Evolution? - The Process of Evolution §Populations evolve, NOT individuals. § In the lice example, the genetic structure of the population of lice changed. § Individuals without a gene for resistance died § Over time, the population changed to mostly resistant individuals © 2013 Pearson Education, Inc.

What is Evolution? – The Process of Evolution § Natural selection – the differential survival and reproduction of individuals in a population § Process by which populations adapt to varying environments § Examples: § Pesticide resistance in crop-eating insects § Antibiotic resistance in infectious bacteria © 2013 Pearson Education, Inc.

What is Evolution? – The Process of Evolution § Microevolution – changes that occur within a species and the characteristics of a population. Easily observed, relatively non-controversial. § Macroevolution – changes that occur, as a result of microevolution, over long periods of time and result in the origin of new species. Controversial among non-biologists. © 2013 Pearson Education, Inc.

What is Evolution? – Theory of Evolution § Ambiguity of the word “theory” § Everyday usage: theory = best guess, or tentative explanation § Scientific usage: theory = body of accepted general principles, supported by many lines of evidence. § Examples: atomic theory, gravity, germ theory. © 2013 Pearson Education, Inc.

What is Evolution? – Theory of Evolution § Theory of evolution § All species present on earth today are descendents of a single common ancestor, and all species represent the product of millions of years of accumulated evolutionary changes. © 2013 Pearson Education, Inc.

What is Evolution? – Theory of Evolution § Theory of common descent © 2013 Pearson Education, Inc.

Animation: Principles of Evolution Click “Go to Animation” / Click “Play” © 2013 Pearson Education, Inc.

Bio. Flix: Mechanisms of Evolution © 2013 Pearson Education, Inc.

Charles Darwin and the Theory of Evolution § Theory of Evolution is sometimes called “Darwinism” because Charles Darwin is largely credited with introducing the concept to mainstream science. § Many philosophers of science before Darwin had notions of organisms changing over time. § Anaximander – Greek philosopher who suggested that humans evolved from fish that had moved onto land § Lamarck – published ideas about inheritance of acquired traits in 1809 © 2013 Pearson Education, Inc.

Charles Darwin and the Theory of Evolution - The Voyage of the Beagle § At age 22, Darwin set sail as ship’s naturalist aboard the HMS Beagle on a five year long trip. § Darwin’s job was to collect and observe “anything worthy to be noted for natural history. ” § Darwin had a book by Lyell, Principles of Geology, which postulated earth was old and changes occurred over long periods of time. © 2013 Pearson Education, Inc.

Charles Darwin and the Theory of Evolution - The Voyage of the Beagle § The following had influences on Darwin during the voyage: § Rainforests of Brazil § Fossils that he collected § Birds and reptiles of the Galapagos Islands © 2013 Pearson Education, Inc.

Charles Darwin and the Theory of Evolution - The Voyage of the Beagle © 2013 Pearson Education, Inc.

Charles Darwin and the Theory of Evolution Developing the Hypothesis of Common Descent § Darwin returned to England in 1836, but did not publish his ideas immediately. § Spent about 20 years refining his ideas § Learned about animal husbandry (selective breeding) § Finally published On the Origin of Species in 1858 © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent § Several lines of biological evidence point to a common ancestor: § Biological classification § Anatomical similarities between organisms § Useless traits in modern species § Shared developmental pathways § DNA similarities § Distribution of organisms on earth (biogeography) § Fossil evidence © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent § Biological classification implies common ancestry. § Linnaean Classification § Gives each species a two-part or binomial name in Latin § Carolus Linnaeus groups organisms in a hierarchy going from broadest to narrowest groupings © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent § Anatomical homology § Mammalian forelimbs have the same set of bones. The underlying structure is similar despite the very different functions. © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent § Useless traits in modern species § Vestigial traits are traits that function in one organism but are greatly reduced in others § For example: § Ostrich and penguins form wings but do not fly because the wings are non-functional § Humans have a tailbone by have no tail © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Developmental Homologies § A consequence of shared developmental pathways is similarity among chordate embryos © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Molecular Homology § DNA similarities: Birds in same genus have DNA that is more similar to one another, while distantly-classified birds have DNA that is less similar. § Molecular clock allows the use of DNA sequence differences between species to determine when they diverged from their common ancestor. Ruddy turnstone Black turnstone Red knot Caspian tern 100% 90% 82% 72% % DNA similarity to Ruddy turnstone Same genus (Arenaria) Same family (Scolopacidae) Same order (Charadriiformes) © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Biogeography § Biogeography is the distribution of species on earth. § Different species of mockingbird found on Galapagos all resemble another species found on the mainland. © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – The Fossil Record § Fossils are remains of living organisms left in soil or rock. § Horse fossils provide a good sequence of evolutionary change within a lineage. © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – The Fossil Record § Fossilization is the formation of fossils © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Fossil Record § Bipedal humans have some unique anatomical traits, such as features of hips, knees, and skull. § Anatomical differences between humans and chimpanzees allow for identification of fossils © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Radiometric Dating § Radiometric dating § Used to determine age of rocks § Relies on decay of radioactive isotopes into daughter products § The rate of decay is measured by the element’s half-life © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Radiometric Dating § Using radiometric dating, scientists have estimated the age of fossil hominims. © 2013 Pearson Education, Inc.

Examining the Evidence for Common Descent – Radiometric Dating § Trends in human evolution § Larger brains, Flatter face, Reduced jaw size © 2013 Pearson Education, Inc.

Are Alternatives to the Theory of Evolution Equally Valid? – The Origin of Life § The origin of life § Evolution is the study of how life changes. § It doesn’t really address issue of how life began. § Experiment evidence does give some clues about beginnings of life. © 2013 Pearson Education, Inc.

Are Alternatives to the Theory of Evolution Equally Valid? - The Origin of Life Gases (CH 4, NH 3, H 2 O, H 2) §The Miller-Urey experiment demonstrated that complex molecules can spontaneously form from simple chemicals. Electrodes 2 Energy applied in the form of heat and electrical charges Condenser Water vapor 3 Organic molecules collected from the system 1 Inorganic molecules, including water and methane, added to system Water droplets Water © 2013 Pearson Education, Inc. Heat Figure 9. 29

§ Evolutionary theory informs all aspects of modern biology. § Evolutionary theory helps us understand the function of human genes. § Evolutionary theory is important to understanding species interactions. § Evolutionary theory is important for predicting the biological consequences of climate change. © 2013 Pearson Education, Inc.

The head lice that have become resistant to the pesticide permethrin demonstrate microevolution. True or False: The individual head lice have evolved. §True. §False. © 2013 Pearson Education, Inc.

Which of the following do not belong in the order Primates. §Monkeys §Humans §Apes §All of the above belong to the order Primates © 2013 Pearson Education, Inc.

Which of the following is an example of a vestigial trait? §A human tailbone §A dolphin’s blowhole §A gorilla’s opposable thumb §A penguin’s flippers © 2013 Pearson Education, Inc.

Where did humans evolve? §North America §Europe §Africa §Galapagos Islands © 2013 Pearson Education, Inc.

True or False: Stanley Miller attempted to recreate conditions on early Earth. After one week, he found that complex organic molecules had formed spontaneously. §True. §False. © 2013 Pearson Education, Inc.

What is shown by the y-axis of this graph? §Percentage of parent element remaining §Time (in millions of years) §Depth of burial §Number of fossils found © 2013 Pearson Education, Inc.