Who am I? What did I do?

Jean-Baptiste Lamarck One of the first to recognize that living things change over time and propose a mechanism Proposed: Individuals can acquire or loose certain traits during their lifetime based on its amount of use or disuse. These acquired changes are then passed on to their offspring. 3 Principles of Lamarck’s Hypothesis Tendency Toward Perfection Use and Disuse Inheritance of Acquired Traits

Charles Darwin One of the first to collect such vast data regarding species change Spent decades cataloguing data and refining theory 1859: Published On the Origin of Species by Means of Natural Selection Proposed: Variation of traits exists within populations Nature selects for specific traits which enable organisms to survive in their environment These individuals are more likely to produce greater number of offspring which will inherit these traits Over time, species changes

Darwin’s Finches

A Quick Comparison Lamarck Darwin 1. Environment changes, creating need for change 2. Individuals develop new features so that they can survive. 3. Newly acquired traits get passed onto offspring. 4. New species 1. Variation of heritable features exists within a population 2. Environment screens out (selects) features contributing to survival, and eliminates others. 3. Those with traits which help survival tend to have more offspring, who inherit these traits. 4. New species

The Fast, The Weird, The UGLY!

How Did These Things Happen? Cheetahs can run faster than 60 miles per hour when in pursuit of prey. How would an evolutionary biologist explain how this ability evolved, assuming their ancestors could only run 20 miles per hour? Many cave organisms are blind. In fact, for many, their eyes have become vestigial (useless) structures. How would an evolutionary biologist explain how this inability to see evolved from sighted ancestors? Naked mole rats have several morphological (relating to the body) as well as behavioral adaptations which allow them to live in a eusocial system within a harsh and unforgiving environment. Make a list of as many of these characteristics as you can. How would an evolutionary biologist explain how these unique characteristics evolved from ancestors which did not possess these traits?

What Have We Learned About Evolution? Evolution proceeds by the process of variation, a genetically random process, and selection, an environmentally driven non-random process. Organisms do not get what they "need" through "inner wants" or through "use and disuse' "Individual intentions do not play a role. Acquired characteristics are not passed on to offspring Mutations are not directed for the benefit of the individual. Evolution is not random. It is driven by the non-random, yet non- directed, process of selection.