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Ecology, Biology 216. Todd Livdahl. Requirements. Essays (3) 20% Lab exercises 20% Quizzes (3) 30% Final Exam (comp) 20%. Essays. Practical ecological problem Population study Species interaction (2 spp or more). Lab Exercises. Interpret ecological data
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Ecology, Biology 216 Todd Livdahl
Requirements • Essays (3) 20% • Lab exercises 20% • Quizzes (3) 30% • Final Exam (comp) 20%
Essays • Practical ecological problem • Population study • Species interaction (2 spp or more)
Lab Exercises • Interpret ecological data • Clarify relationship between field observations and central concepts • Develop skills in computation and analysis
Quizzes and Final • 3 Quizzes, equal weight • Full class in length • Concept-driven • Qualitative
Substitution Final = 2 x (quiz) If Final/2 > (lowest quiz), then Final/2 will be substituted for the lowest quiz score Example: Quizzes-- 25 27 19 (out of 30) Final-- 44 (out of 60), 44/2 > 19 lowest quiz score (19) is replaced by (22) NO MAKEUP QUIZZES
First Essay Due Jan. 28 Description of problem Justification as a problem Solution strategies possible or solution strategies attempted Problems arising from solutions 3-4 pages should suffice
Borneo Mosquitoes Malaria Wasps Caterpillars Roof Thatching
The Borneo Cat Crisis Housefly control Cats Rats Geckos Houseflies
The Coconut Leaf-mining Beetle Crisis, Fiji 1850-1880 Early development, plantations 1880-1900 Intensive cultivation and shipping 1900-1920 Gradual increase in impact of beetle 1920 Outbreaks threaten Fiji economy
Natural Coconut Community Mite 4 Mite 3 Mite 2 Ants Lizards Ants Mite 1 Birds Beetle: Adult Egg Larva Pupa Coconut
Intensive Cultivation: Mite 5 Mite 4 Mite 3 Mite 2 Ants Lizards Ants Mite 1 Birds Beetle: Adult Egg Larva Pupa Coconut
Container-breeding Mosquitoes Adults Pupae Eggs Larvae Container habitat
Natural examples Treeholes Bromeliads Pitcher plants Bamboo stems Leaf axils Crab holes Snail shells Snow-melt pools Water-filled hoof prints Domestic examples (short list) Bird baths Cemetery urns Discarded junk Bottle caps to Bath tubs Downspouts, eave troughs Cisterns Trash barrels Tires Container Habitats
Aedes albopictus and the New Globalism Distribution: 1983: tropical and temperate Asia, Pacific Islands 1984, 1985: Memphis, Tennessee Houston, Texas-- the most abundant mosquito in a pile of used tires First discovery of Aedes albopictus in Western Hemisphere
Aedes albopictus since 1985 Numerous US localities South America, esp. Brazil Central America, Mexico Europe (Italy, Albania) Caribbean Bermuda
3 From countries in the range of albopictus From countries outside albopictus range 2 1 0 1970 1975 1980 1985 Used Tires Imported (millions) Used Tire Importation Year
Long-range Prospects for Invasion Depend on: Adaptations to physical challenges Success in dealing with native community • Competition with native species • Other interactions with native species (predation, hatch inhibition, parasitism)
100 U.S. Beijing Asian 80 Korea Tokyo Kyoto 60 Nagasaki Difference (%H, Long - %H, Short days) Shanghai 40 20 0 0 10 20 30 40 50 Latitude Origin from temperate Asia KEY ADAPTATION: Winter Diapause
Potential interactions with resident species North: Competition with treehole mosquitoes in treeholes and tires South: Competition with Aedes aegypti in open tire habitats Competition with treehole mosquitoes in forested tires and treeholes Predation Parasitism
Topics, 2nd & 3rd Lecture 2nd Lecture Origins of Ecology Influence of Evolution Determining Inheritance 3rd Lecture Reasons to study Evolution Criteria for Natural Selection Forms of Selection
A sample of calculations involved in predicting changes in allele frequencies. The initial frequency of the a allele (p) is 0.4. Genotype aa ab bb Total Number of zygotes 30 20 50 100 at time 0 Survival fraction 0.5 0.8 0.9 Number of adults 0.5x30 = 15 16 45 76 Number of successful 10 5 2 gametes per adult Number of 10x15=150 80 90 320 successful gametes produced Fitness 0.5x10/2=2.5 2.0 0.9 New allele p=(150+80/2)/320=0.59 q=0.41 frequencies Next fraction 0.592^2=0.35 2x0.59x0.41=0.48 0.402^2=0.17 1 of zygotes Number of 0.35*320/2=56.4 77.2 26.4 147.8 zygotes at time 1
Selection against allele b Figure 1. Changes in the frequency of allele a through time. Selection in this case is against allele b. For both cases, Waa = 1 and Wbb=0.5. For curve 1, Wab=0.5; for curve 2, Wab=1.
Warwickshire, England Costa Rica U.S.
Inheritance: aa: blue ab: orange bb: orange OR: aa: blue ab: blue bb: orange Mainland Orange environment Population is all orange p = 0 Dispersal from Mainland to Island: fixed fraction of individuals on island (I) have been born on the mainland Island Blue environment Blue individuals (initially rare) survive at higher rate
Changes in the frequency of allele a through time for different fractions of immigrants to an island population. Selection in this case is against a dominant allele (b). I denotes the fraction of immigrant individuals arriving into the population with each generation. The initial frequency of the a allele in the island population is 0.2; mainland frequency=0. Fitness values are: Waa=1, Wab=0.5, Wbb=0.5.
Changes in the frequency of allele a through time for different fractions of immigrants to an island population. Selection in this case is against a recessive allele (b). I denotes the fraction of immigrant individuals arriving into the population with each generation. The initial frequency of the a allele in the island population is 0.2; mainland frequency=0. Fitness values are: Waa=1, Wab=1, Wbb=0.5.
Inheritance: aa: wingless ab: winged bb: winged OR: aa: wingless ab: wingless bb: winged Genotypes have same fitness Mainland Population is all winged p = 0 Dispersal from Mainland to Island: fixed fraction of individuals on island (I) have been born on the mainland (all winged, all bb) Island Low initial fraction wingless (aa) Some fraction of winged individuals disperse away from the island
Low I High I Low I High I
Genetic Drift N=10 N=20
N=20 N=100 Drift N=1000 Chance deviations in frequency result in loss of genetic variation, especially in small populations
Measuring Genetic Variation Gel electrophoresis Alleles: Pgm 1 2 3 Genotypes: Etc… 12 22 23 24 12 Do this for many individuals Do this for many loci Heterozygotes Heterozygosity: fraction heterozygous/locus
Genetic Variation Finnish Spittlebugs
Oropendula Oropendula egg Giant Cowbird mimetic non-mimetic Cowbird eggs
Number of nestling Oropendula in nests With CowbirdsWithout Cowbirds With Bot-fly parasites 57 382 Without Bot-flies 619 42
Fledgling success of oropendulas in discriminator and nondiscriminator colonies relates to the presence or absence of cowbirds: