1	Evolution by Natural Selection Change of allele frequency is the most basic evolutionary change.
2	Reading Assignment The reading for today’s lecture is chapter 23. Focus attention on the ‘Key Concepts’. Know major features of evolution as understood before sequence information was available.
3	Evolution, modern definition A necessary and sufficient condition for biological evolution is change of gene frequency. Necessary means that without gene frequency change there is no evolution. Sufficient means that if gene frequency changes then biological evolution has occurred.
4	Selection that is not evolution Selection implies differential survival according to phenotype. If phenotypic differences do not have a genetic basis, then the differential survival will not result in any change in the genotype frequencies of the next generation. No genetic change means no evolution.
5	Gene frequency change whose basis is unknown If gene frequency changes, a population has evolved, even if we do not understand the basis for the change. You will learn that phylogeny is primarily based on the accumulation of genetic changes that have no functional differences (equivalent alleles are said to be neutral).
6	Evolution is logical Once we except that: Not all phenotypes are equally likely to be represented in next generation because some function better than others, AND that phenotypic differences often have a genetic basis, Then we have EVOLUTION.
7	Historical Evolution Darwin proposed: The earth was millions of years old Species changed gradually thru time “descent with modification” New species had arisen many times in the history of the earth Species that had existed were extinct
8	History of Life Rock containing fossils could be dated in various ways. Sequence in sediments Rates of accumulation of sediment Radioactive decay When fossils organized by time sequences of change were evident. Continuity of morphology, i.e. gradual changes
9	Hierarchy of species Taxonomic hierarchy of Linnaeus is consistent with the notion that species change continually and irreversibly. Biogeography, that fact that species in different continents were often more related to each other than they were to species playing similar roles of different continents was consistent with descent with modification.
10	Organization of Lineages = Phylogeny Though originally based on similarities of hard parts like bones, homology is currently studies almost exclusively through comparison of DNA sequences. Comparison of sequences Alignment Counts of differences (the difference matrix)
11	Human Evolution Humans, Chimpanzees and Gorillas are about equally separated using modern phylogeny, but humans are slightly more closely related to chimpanzees. Humans are NOT derived from chimps. Chimps and humans share a common ancestor. Both chimps and humans changed since that time.
12	EVOLUTION TODAY Understanding evolution is crucial to understanding many changes going on in the world today. ANTIBIOTIC RESISTANT DISEASES PESTICIDE RESISTANT INSECTS Concept of natural selection even provides a framework to understand how law structures inheritance.
13	EVOLUTION OF RESISTANCE As an antibiotic comes into widespread use there are more opportunities for resistant mutants to arise. Some diseases, especially sexually transmitted infections (STI), are now very difficult to treat because most strains are resistant to antibiotics.
14	PESTICIDES We will consider both: The evolution of resistance to pesticides by the “target” organisms, and The “evolution” of human practices in trying to control pest organisms.
15	TREND: General to specific In late 19^th century, metal compounds, arsenic & copper were widely used. These compounds were toxic to all life. During the 20^th century compounds, like DDT, that were specific to insects came into widespread use. Pheromones can be used to target specific pest species.
16	INTEGRATED PEST MANAGEMENT Uses knowledge of population biology to get the same level of pest control with less total amounts of pesticide. Find vulnerable stages of the life cycle . Minimize damage to predators of pest. Manipulate environment (crop residues) to minimize carry-over. Evaluate economics of pesticide use.
17	Species are always changing Besides the disease/pest cases already presented, a variety of studies have shown that the morphology of some species is changing in response to events. Galapagos finch story in text. Animal populations after extreme events such as hurricanes
18	Is evolution progressive? Text argues that ‘natural selection is not progressive’ (p511), BUT I assert that the enzymes that fix nitrogen are more efficient today than they were 500 million years ago. Evidence is not easy to gather, but I assert evolution is not just ‘same old same old’.
19	Fitness Defined Absolute fitness (for a specific time period) = abundance at later time/abundance at earlier time. Relative fitness (for a specified time period and when there are at least two types) of A to B = absolute A/absolute B
20	Fitness and Evolution Fitness can be measured by changes in population size. Most often one is interested in relative fitness of types within a population. Types that increase faster (than other types) have greater fitness. Models that include chance are different than models that do not.
21	Question The evidence for evolution comes from both historical evidence such as fossils and their dating, and from changes that have occurred within your lifespan, which type of evidence is more persuasive to you and why?
22	Vocabulary Allele frequency Necessary Sufficient Differential survival Extinct Integrated pest management Rate of accumulation of sediment Biogeography Lineage Homology Resistance to biocides Fitness