Lecture Outline
 
Evolution & Ecology
Biology 3133
Instructor: C. Ray Chandler

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This course outline corresponds to the outline you will see during lecture. The course topics and their organizational relationships are shown in black. Readings from the textbook (Biology, 7th ed by Campbell and Reece), as well as helpful figures and tables, are shown in red. The take-home message or theme of each topic is given in blue.


I. INTRODUCTION
A. Course Policies
1. instructor
2. text and readings
3. tests and grading
4. schedule
B. Course Content (pp. 2-27)
1. definitions - evolution is the study of genetic change in populations and ecology is the study of the interaction between organisms and their environment
2. why study evolution and ecology? - evolution and ecology unify the biological sciences and form the basis for understanding many current environmental, health, and social issues.
a. biological significance
b. practical significance
3. how do we study evolution and ecology? - evolution and ecology are sciences that explore testable hypotheses about all levels of the biological hierarchy
a. methods
b. levels of analysis
C. Examples (pp. 535, 267, 466)
1. antibiotic-resistant bacteria - natural selection can work over time spans detectable by humans and can affect human health
2. sickle cell allele (Fig. 23.13) - natural selection plays a role in the occurrence and treatment of some human diseases
 
II. THE SOURCE OF GENETIC VARIATION
A. Cell Division (pp. 218-224; 238-249)
1. mitosis (Figs. 12.6, 13.9) - mitosis produces genetically identical daughter cells and is involved in asexual reproduction, growth, and repair
2. meiosis (Figs. 13.8, 13.9) - meiosis reduces chromosome number by half and is associated with sexual life cycles
B. Meiosis, Sex, and Genetic Variation (pp. 238-249)
1. a sexual life cycle (Fig. 13.5, 13.6) - sexual life cycles involve alternation among meiosis, mitosis, and fertilization
2. terminology - to understand the role of meiosis in these cycles, you must know some important terminology
3. how meiosis works (Figs. 13.7, 13.8, 13.9, 13.10) - meiosis involves replication (copying) of DNA followed by two rounds of cell division
4. meiosis creates variation (Fig. 13.1, 23.1) - meiosis (sexual reproduction) creates gentically variable individuals
C. Genetic Variation and Inheritance (pp. 251-270)
1. Mendel and particulate inheritance (Fig. 14.4) - Mendel discovered that each individual carries two alternative forms for each gene, and that each form (allele) is passed from generation to generation by simple rules of probability
2. monohybrid crosses (Figs. 14.3, 14.4, 14.5, 14.6, 14.7) - Mendel developed rules to understand inheritance of a single trait (one locus), including expected phenotypic ratios in offspring
3. dihybrid crosses (Fig. 14.8) - Mendel developed rules to understand inheritance for two traits (two loci), including expected phenotypic ratios in offspring
4. complications - but, several factors can alter the simple rules of mendelian inheritance by complicating the relationship between genotype and phenotype
a. incomplete dominance (Fig. 14.10)
b. codominance
c. multiple alleles (Table 14.2)
d. pleiotropy
e. epistasis (Fig. 14.11)
f. polygenic inheritance (Fig. 14.12)
5. genes versus environment (Fig. 14.13) - furthermore, an individual's phenotype depends on both genes and environment
D. Chromosomal Basis for Inheritance (pp. 274-290)
1. inheritance has a chromosomal basis (Fig. 15.2) - because genes are carried by chromosomes, Mendel's laws have their physical basis in the behavior of chromosomes during cell division
2. linked genes - genes on the same chromosome are linked and often inherited as a unit, violating the simple rules of mendelian inheritance
a. detecting linkage (Figs. 15.5)
b. linkage maps (Fig. 15.7, 15.8)
3. sex-linked genes (Figs. 15.10, 15.11) - genes on the sex chromosomes are sex-linked and also have an unusual pattern of inheritance
4. chromosomal alterations - an abnormal number or structure of chromosomes can result in a number of problems or disorders
a. problems in chromosome number (Fig. 15.12, 15.15)
b. problems in chromosome structure (Fig. 15.14)
E. Population Genetics (pp. 454-458)
1. the gene pool - the gene pool is the sum total of all alleles in a population at a given time
a. allele frequencies
b. genotype frequencies
2. Hardy-Weinberg theorem (Fig. 23.5) - the frequencies of alleles and genotypes in the gene pool will not change as a result of the shuffling caused by meiosis and sexual reproduction
 
III. POPULATION GROWTH
A. Characteristics of Populations (pp. 1136-1139)
B. Basic Population Growth (pp. 1143-1147)
1. exponential growth (Fig. 52.9, 52.10) - populations have the potential to grow without limits (exponentially) if placed in environments with unlimited food, space, shelter, etc.
2. logistic growth (Figs. 52.11, 52.12, 52.13) - however, in most real-world situations, the environment limits growth and population size levels off at a carrying capacity (logistic growth)
C. Factors Limiting Population Growth (pp. 1148-1152)
1. density-dependent factors (Figs. 52.14, 52.15) - the limits on population growth can vary with density of the population (e.g., food availability)
2. density-independent factors (Fig. 52.14) - or the limits can exert their effects independent of population density (e.g., harsh weather)
3. population regulation (Fig. 52.14) - ultimately, both types of factors interact to determine population size
 
IV. POPULATION CHANGE
A. Background (pp. 438-441)
1. a young, unchanging world - historically, popular opinion held that the earth was only a few thousand years old and was inhabited by unchanging forms of life
2. catastrophism - work with fossils lead to the idea that life has changed through time, but only due to unusual events (catastrophes)
3. uniformitarianism - geologists provided evidence that in reality the same processes operating today have operated in the past
4. gradualism - furthermore, evidence suggested that these processes have worked gradually over large spans of time
B. Darwin (pp. 441-443)
1. a brief history (Fig. 22.2, 22.5) - Darwin, an English biologist, was influenced by observations of variation in organisms and wrote The Origin of Species in 1859
2. the reality of evolution - he drew on several lines of evidence to convince most people that evolution had occurred
a. distribution (Fig. 22.17)
b. fossils (Fig. 22.18)
c. comparative anatomy (Fig. 22.14)
d. modern evidence (Fig. 22.12, 22.13, Fig. 22.16)
3. a mechanism for evolution - even more importantly, he provided a mechanism, natural selection, for how evolution occurs
4. evolution as a theory - evolution is a well-established explanatory framework in biology (i.e., a scientific theory)
C. Selection (pp. 462-479)
1. natural selection - individuals with alleles that make them better able to survive and reproduce tend to pass these alleles to future generations in a process called natural selection
a. types of selection (Fig. 23.12)
1. directional (Fig. 23.12)
2. stabilizing
3. disruptive (Fig. 23.12)
b. raw material
c. is there enough variation?
2. sexual selection (Fig. 23.15) - sexual selection favors individuals with traits that enhance mating success
a. definitions
1. intrasexual
2. intersexual
b. causes
3. the unit of selection - in general, selection favors traits that benefit individuals, not groups
4. limits to selection - however, selection does not shape perfect organisms because of several constraints
D. Other Factors Causing Evolution (pp. 459-462)
1. assumptions of Hardy-Weinberg - the Hardy-Weinberg theorem assumes infinitely large populations, no migration, no mutation, random mating, and no selection; violation of these assumptions results in evolution
2. genetic drift (Figs. 23.7, 23.8) - in small populations, allele frequencies can change by chance alone
3. gene flow (migration) - movement of individuals between populations causes a change in allele frequencies
4. mutation - mutations represent an immediate change in allele frequencies in a population
5. nonrandom mating - selective mating tends to change genotype frequencies in a population
6. selection - selection favors certain alleles, thus increasing their frequency in a population
 
V. POPULATIONS AND THEIR ENVIRONMENT
A. A Simple Ecological Question
B. Factors Limiting Distribution (pp. 832-834; 1080-1092)
1. dispersal (Fig. 50.7) - organisms can fail to occur in an area because they cannot (or have not) reached the site
2. abiotic factors (Fig. 40.12) - if organisms can reach an area, they still may not occur there because of unfavorable abiotic factors such as temperature and moisture
3. biotic factors (Fig. 50.8) - finally, organisms can be limited by the occurrence or activity of other living things
C. Biotic Interactions (pp. 1159-1171)
1. types of biotic interactions - biotic interactions can be classified by whether the participants benefit (+) or suffer (-) from the interaction
2. competition - competition is a (-,-) interaction; both species experience reduced fitness
a. definitions
b. basic model
c. outcome in nature (Figs. 53.2, 53.3, 53.4)
3. predation - predation, broadly defined, is a (+,-) interaction; one species benefits, one pays a cost
a. definitions
b. basic model (Figs. 52.21)
c. predation as a selective force (Figs. 53.5, 53.6, 53.7, 53.8)
4. mutualism (Fig. 53.9) - mutualism is a case of mutual benefit (+,+)
5. commensalism (Fig. 53.10) - commensalism is a (+, 0) interaction; one species benefits and one is unaffected
D. Life Histories (pp. 1139-1143; 1152-1156)
1. what is life history? - organisms have particular patterns of survival and reproduction (life history) to deal with the challenges posed by the environment
2. demography - life histories are studied by analyzing age-specific birth and death rates, the science of demography
a. life tables (Table 52.1, 52.2)
b. the human example (Fig. 52.22, 52.25)
3. evolution of life histories - organisms evolve predictable life histories in response to particular environments
a. age at first reproduction
b. number/size of young per breeding attempt (Figs. 52.7, 52.8)
c. number of reproductive events (Fig. 52.6)
d. life span
 
VI. ORIGIN OF DIVERSITY
A. Key Concepts (pp. 472-473)
B. Evolution of Diversity (pp. 473-487, 491-495)
1. speciation - one species can split into two by the process of speciation
a. isolating mechanisms (Fig. 24.4)
1. prezygotic
2. postzygotic
b. modes of speciation (Fig. 24.5)
1. allopatric (Fig. 24.6, 24.7)
2. sympatric (Fig. 24.8, 24.9)
2. macroevolution - ultimately, entirely new families, orders, etc. can evolve and we call this macroevolution
a. a brief history of life (Table 26.1)
b. reconstructing the history of life
1. the fossil record (Figs. 25.3, 25.4)
2. phylogeny (Figs. 25.8, 25.9, 25.10, 25.11)
c. processes (Figs. 24.14, 24.15, 24.16, 24.17, 24.18, 24.19, 24.20)
C. Ecology of Diversity (pp. 1165-1180)
1. patterns - some areas have predictably greater diversity of living things than other areas
a. latitude (Fig. 53.23)
b. elevation
c. continental vs. insular
2. explanations - but, there are several possible explanations for why one area has more species than another area
a. spatial heterogeneity
b. competition (Fig. 53.3, 53.4)
c. predation (Fig. 53.16, 53.17)
d. disturbance (Fig. 53.21, 53.22)
e. productivity
f. time/stability
 
VII. ECOSYSTEMS
A. Components of an Ecosystem
B. Energy (pp. 1184-1194)
1. the role of photosynthesis - most life on earth depends on photosynthesis to capture energy from the sun
2. productivity (Fig. 54.4, 54.5) - solar energy is captured by plants (gross primary productivity), turned into plant biomass (net primary productivity), and passed on other organisms (secondary productivity)
3. food chains - energy moves through an ecosystem as organisms from one trophic level consume those from another level
a. structure (Figs. 54.2)
b. function (Figs. 54.10, 54.11, 54.12, 54.13)
4. example of a human-controlled food chain (Fig. 54.14) - we can manipulate food chains to maximize the energy available to humans
C. Matter (pp. 1195-1206)
1. carbon (Fig. 54.17, 54.24, 54.25) - carbon cycles globally among the atmosphere, soil, ocean, and living things
2. oxygen (Fig. 54.17, 54.26, 54.27, 54.28) - respiration and photosynthesis are important biotic processes in the oxygen cycle
3. nitrogen (Fig. 54.17) - nitrogen is abundant in the atmosphere but only a few processes can make it available to living things
4. sulfur (Fig. 54.21, 54.22) - sulfur cycles globally with major inputs from both humans and natual sources
5. phosphorous (Fig. 54.17) - phosphorous cycles locally and living things can play an important role in its movement
 

 
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