Lecture_2_Mechanisms_of_Evolution

Lecture_2_Mechanisms_of_Evolution - Evolution What and How...

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
6/15/2011 1 Evolution: What and How LS1: Summer Session A June 22, 2011 “Nothing in biology makes sense except in the light of evolution.” Theodosius Dobzhansky March 1973 Theodosius Dobzhansky (1900-1975) Evolution… Shows the relatedness of all of life Explains the differences between organisms Explains how organisms can adapt to varied or changing environments Works on many levels from molecules to species What is evolution? Descent with modification Change in allele frequencies over time Charles Darwin No discussion of evolution would be complete without mentioning Charles Darwin But he was not the first to suggest that evolution occurred Pre-Evolution Aristotle’s Scala Naturae was the prevailing notion prior to Darwin’s Theory of Evolution by Natural Selection Species were fixed and immutable
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6/15/2011 2 Early ideas of evolution Georges-Louis Leclerc, Comte de Buffon (1707-1788) Jean-Baptiste de Monet, Chevalier de Lamarck (1744-1829) Buffon’s observations Buffon’s studies on animals showed anatomical similarity Despite a wide diversity of form and function, the basic bone architecture was the same Common ancestry? Lamarck’s ideas of evolution Lamarck believed that the use or disuse of traits could cause them to be altered over an individual’s lifetime He suggested these differences could be inherited by offspring Charles Darwin & The Origin Evolution as a concept was known in the pre- Darwinian world However, The Origin provided a suitable mechanism to explain how evolution could occur Darwin’s Voyage At age 22, Charles Darwin began a five- year, round-the-world voyage aboard the HMS Beagle In his role as ship’s naturalist, he collected and examined the species that inhabited the regions the ship visited Voyage of the Beagle
Image of page 2
6/15/2011 3 The Galapagos Islands Galapagos Finches Darwin’s observations Many species of finch on the Galapagos Islands Clearly from similar origin Why so different? Finches were clearly adapted to different lifestyles. How did they get that way? Darwin was a pigeon breeder and recognized the power of selective breeding Artificial Selection Darwin’s Contribution to Biology Darwin’s Theory of Evolution by Natural Selection Variation Heritability Differential reproductive success
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6/15/2011 4 Darwin’s Theory in a Nutshell Observation 1: All populations have the potential to grow exponentially Observation 2: A population does not grow exponentially Inference 1: There is a competition for resources Struggle for existence Thomas Malthus posited the idea that more individuals are born than can survive Thomas Robert Malthus, 1766-1834 Darwin’s Theory in a Nutshell
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern