Definition of Ecology n n 1866 Ernst Haeckel

Definition of Ecology n n 1866 Ernst Haeckel: the comprehensive science of the relationship of the organism to the environment 1927 Charles Elton: Scientific natural history 1963 E. P. Odum: The study of the structure and function of nature 1972 C. J. Krebs: The scientific study of the interactions that determine the distribution and abundance of organisms

Ecological spectrum Biosphere, Landscape, Ecosystem, Community, Population, Organism, Organ system, Organ, Tissue, Cell, Subcellular organelles, Molecules Branches of Ecology Chemical, Molecular, Physiological, Behavioral, Population, Community, Ecosystem, Landscape, Evolutionary, Theoretical, Conservation and management,

Journals: Behavioral Ecology, Biological Conservation, Chemical Ecology, Conservation Biology, Conservation Ecology, Ecological Application, Ecological Modeling, Ecological Monograph, Ecologist, Ecology, Environmental Management, Evolutionary Ecology, Functional Ecology, Journal of Animal Ecology, Journal of Applied Ecology, Journal of Wildlife Management, Landscape Ecology, Molecular Ecology, Oecologia, Oikos, Trends in Evolution and Ecology, etc.

Methods of studying ecology n To understand, describe, explain, predict and control n Scale n Lab experiment, field experiment, natural trajectory experiment, natural snapshot experiment, mathematical model

Ecology of forest birds n 5 warbler sp. of similar ecological requirement n Feeding zones n In the presence or absence of other species n Competition and partitioning

Energy budget of bumblebee n How to keep warm in cold environment? n Energy gain for feeding – energy loss from flying, feeding and keeping warm n Lab and field studies n Number and kinds of flower visited, sugar content of flower n Energy loss at different temperature

Brown trout v. s. Native Galaxias n Fish → Mayfly nymph → algae n Activity pattern (lab and field exp. ) n Habitat preference (natural exp. ) n Community effect (field exp. )

n Trophic cascade – effects flowing down from one trophic level to the next and the next n Energy flow n Primary production: trout >> Galax n Secondary production: trout >> Galax

Succession of old fields n Natural trajectory vs. natural snapshot n Correlation vs. mechanism n n within field comparison indicated introduced sp. ↑and prairie sp. ↓ as N↑ Field experiment n sp. composition and N supply

Nutrients in the rain forest canopy n Epiphytes mats ~ ½ to 4 x of the nutrient content of the foliage of the canopy trees n Photosynthesis, migratory birds, bats

Fox-rabies (math model) n Assumptions: no recovery or immune, no migration, random contact n Biology: life span 2 yrs. , 1 cub/yr, latent phase 28 days, die 5 days after becoming infectious

N=S+L+I d. S/dt = (b-d)S -αSI d. L/dt = αSI - d. L - βL d. I/dt = βL - d. I - γI α - contact rate β - reaction rate γ - rabies-induced mortality

Merits of model n Summarizing current knowledge n Approximation and simplification n Hypotheses testing n Exploring scenarios and situations n Caution in evaluation and prediction

Factors affecting the abundance and distribution of species n Historical factors n n evolution and speciation continental drift geological and climatic changes Abiotic factors n chemical and physical environment

n Biotic factors n competition, predation, mutualism, etc. n Dispersal n Behavioral factors n Human factors

Darwinian evolution by natural selection n individual variation n variation is heritable n differential reproductive rate n the interaction between the characteristics of individual and the environment

Fitness n a measure of biological success n # of gene or genome put into the next generation n the proportionate contribution that an individual makes to future generation

The fittest individual n those that leave the greatest # of descendants n those that transport more gene to the next generation

Example n Model: an annual, only one gene, asexual reproduction, reproduce only once in life time. n 5 genotypes: A, B, C, D, and E n G, S, F = proportion of energy devoted to growth, survival (against predator), and fecundity

# of seed Genotypes 10 A 10 B 10 C 10 D 10 E Total Spring/Summer 2 large 2 seeds 9 small 1 seeds 2 small 4 seeds 4 medium 5 seeds 5 med-small 4 seeds Fall Survival 4 9 8 20 20 61 G: F: S in A=6: 1: 1, B=1: 1: 6, C=1: 6: 1, D=1: 1: 1, E=1: 1: 2

Genotype frequency before after one generation A 10/50=0. 2 4/61=0. 06 B 0. 2 9/61=0. 15 C 0. 2 8/61=0. 13 D 0. 2 20/61=0. 33 E 0. 2 20/61=0. 33 Fitness = # of gene/genome put into the next generation Fitness of D&E = 20/10 = 2 Fitness of C = 8/10 = 0. 8 Fitness of B = 9/10 = 0. 9 Fitness of A = 4/10 = 0. 4

Questions n Is the population biologically successful? n Are those genotypes equally successful? n What if increase herbivory?

Within species variation n Perennial Achillea lanulosa, transplant and reciprocal transplant n Natural selection by pollution n n Industrial melanism Natural selection by predation