“Nothing in biology makes sense except in the light of evolution.” Biologist (1900 – 1975) _____. Darwin Charles Darwin in later yearsCharles Darwin at age 31

What is Evolution? Evolution - the gradual change in a species over time.

Darwin at age 31 in 1840 (4 years AFTER his voyage)

Darwin’s Voyage of Discovery A reconstruction of the HMS Beagle sailing off Patagonia (South America).

The Voyage of the Beagle

The Galapagos Islands

Darwin’s Finches Observe the different feather colors, and different size and shape of the beaks.

Adaptation- A trait that helps an organism survive and reproduce. Ex. The Finch’s Beak helps it to obtain food.

Darwin’s Observations Darwin’s Conclusions In your own words! Draw this table with only the column headings. Make this table VERY LARGE!

Darwin’s Observations and Conclusions Observation 1Species over-produce Observation 1: Species over-produce (reproduce in excess). Many more are produced than can ever survive to adulthood. Conclusion #1: (competition) Conclusion #1: When the environment cannot support the number of individuals, it leads to a struggle for existence (competition) among individuals, with only some of offspring surviving in each generation. Observation 2Environmental resources (food, water, habitat) are limited. Observation 2: Environmental resources (food, water, habitat) are limited. Over-production + limited resources  competition

In other words…. When there are too many organisms in one place, they have to compete for: –Food –Living Space –Water »They do not all survive.

Darwin’s Observations and Conclusions Observation 3variation Observation 3: There is variation in characteristics of individuals in a population - no two individuals are exactly alike. Observation 4: inheritablepassed from parents to offspring). Observation 4: Much of this variation between individuals is inheritable (passed from parents to offspring).

Variation in Birds

Variation in Dogs

Variation in Humans

Conclusion 2: Survival in the struggle for existence depends partly on the inherited characteristics of individuals. Individuals who inherit characteristics best fitted to their environment are more likely to survive and reproduce than less fit individuals. Darwin’s Observations and Conclusions Inherited Variations + Competition  Natural Selection

Survival of the Fittest! Organisms that are best suited (adapted) to their environment will survive and reproduce!  Their offspring will inherit this helpful adaptation and will survive and reproduce. And so on….. In other words….

Example Page 143

Example Page 144

gradual change in a population Conclusion 3: The unequal ability of individuals to survive and reproduce leads to a gradual change in a population, with favorable characteristics accumulating over generations. Theory of Evolution Taken together, these three conclusions are a statement of Darwin’s Theory of Evolution. Darwin’s Observations and Conclusions Natural Selection + Time  Evolution

Darwin’s Points over-produce Species over-produce (reproduce in excess). Many more offspring are produced than can ever survive to adulthood. Limited resources competition Limited resources (food, water, shelter) lead to competition for these resources. variation advantage There is variation within the population. Some of these variations have an advantage over others. selected inherit Those species members with an advantage will be selected to survive and reproduce, and their offspring will inherit this advantageous trait. species will change over time As a consequence the species will change over time.

V = Variation V = Variation : All life forms have variations (differences in traits between members of a species). Some examples in humans: height, skin color, eye color I = Inheritance S = Selection I = Inheritance : Genetic traits are inherited from parents and are passed on to offspring. S = Selection : Organisms with traits that are favorable to their survival get to live and pass on their genes to the next generation. T = Time T = Time : Evolution takes time; usually, millions of years. Evolution can happen in a few generations (for example, in bacteria and viruses), but major changes take long periods of time. V I S T V*I*S*TV*I*S*T

Evolution “Equations” O Over- production + LR Limited Resources CCompetition

Evolution “Equations” IV Inherited Variations + CCompetition NS Natural Selection

Evolution “Equations” NS Natural Selection + TTime EEvolution

Resistance to antibacterial soap Generation 1: 1.00 not resistant 0.00 resistant How natural selection works

Generation 1: 1.00 not resistant 0.00 resistant Resistance to antibacterial soap How natural selection works

Resistance to antibacterial soap mutation! Generation 1: 1.00 not resistant 0.00 resistant Generation 2: 0.96 not resistant 0.04 resistant How natural selection works

Resistance to antibacterial soap Generation 1: 1.00 not resistant 0.00 resistant Generation 2: 0.96 not resistant 0.04 resistant Generation 3: 0.76 not resistant 0.24 resistant How natural selection works

Resistance to antibacterial soap Generation 1: 1.00 not resistant 0.00 resistant Generation 2: 0.96 not resistant 0.04 resistant Generation 3: 0.76 not resistant 0.24 resistant Generation 4: 0.12 not resistant 0.88 resistant How natural selection works

Evolution’s Core Principle Natural Selection “I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection.” —Charles Darwin from "The Origin of Species"

members.tripod.com/~Alphacentaur/ X-men.JPG Mutation = random, inheritable changes in DNA sequences that introduce new alleles into a species’ gene pool.

The Missing Link: HOW does Evolution occur? Darwin Darwin’s theory mechanism A major problem in Darwin’s theory was the lack of a mechanism to explain natural selection. How How were favorable variations (adaptations) passed on to later generations? Mendel missing link With the rediscovery of Mendel’s work in the first half of the 20th century, the missing link in evolutionary theory was forged. Darwin’s theorygenetics modern synthesis Darwin’s theory supported by genetics is known as the modern synthesis.

Is evolution progressive? This is not an easy question to answer. From a plant's perspective, the best measure of progress might be photosynthetic ability; from a spider's it might be the efficiency of its web in catching insects. The problem is that we humans think it’s “all about us”! We often define progress by how it affects our species. But that definition is anthropocentric.anthropocentric we are just one of many leaves on the tree. It is tempting to see evolution as a grand progressive ladder with Homo sapiens emerging at the top. But evolution produces a tree, not a ladder — and we are just one of many leaves on the tree.

The “Tree of Life” Animals are the newcomers in the evolution of life on Earth. All living things are “cousins”; some more distant than others.

Plant Evolution Flowering plants Cone-bearing plants Ferns and their relatives Mosses and their relatives Green algae ancestor Flowers; Seeds Enclosed in Fruit Seeds Water-Conducting (Vascular) Tissue

Evolution links Evolution Exploratour Understanding Evolution Univ. Calif. Museum of Paleontology Evolution: PBS