Topic: Autecology - the ecology of single species

Lecture 2

Section objectives:

1. Ecological factors: abiotic, biotic, anthropogenic

2. Limiting factors: critical factors and tolerance limits. Liebig 's law of the minimum and Shelford's principle of tolerance limits

3. Biotic and abiotic interactions

1. Ecological factors:

Abiotic factors - the nonliving components of an ecosystem.

Biotic factors - the living components of an ecosystem.

Anthropogenic factors – factors that are caused by human activities.

Ecological factors
Abiotic	Biotic	Anthropogenic
Meteorological: climatic; temperature, humidity, pressure, wind	Zoogenic: animals relationships	Economical: using natural resources for survival
Geophysical: radiation, relief, magnetic	Phytogenic: plants relationships	Technogenic: using machines and complex technical equipment to reach definite purposes
Chemical: components of atmosphere, water, soil chemistry and structure, acidity	Microorganismic: microorganisms relationships

physical factors interact with one another: Example: Rains → Flood → Change the chemical soil composition.

Biotic factors also interact in many ways:

Possible interactions between Organisms in a community
Kind of interaction	Organism 1	Organism 2
Competition [interspecific = between species, intraspecific = between individuals of one species]	harmed	harmed
Predation[predator-prey system: herbivory (rabbit-grass; giraffe-trees), carnivory (wolf-deer, fox-hare), omnivory (bear-elk, or fruits)]	benefited	harmed
Symbiosis:the relationship between different species living in close association with one another:
Parasitism [a parasite secures its nourishment by living on or inside another organism called the host – helminthes; fleas, lice]	harmed	benefited
Allelopathy [the type of interaction in which one organism release allelochemicals that harm another organism – flowers with strong smell kills other: tulip-narcissus, rose-pink, lily of the valley, lilac]	benefited	harmed
Commensalism [interaction that benefit one participant and have no effect on the other – remoras and sharks; leguminous-nitrogen fixing bacteria]	benefited	unaffected
Protocooperation [is a noncompulsory interaction which can also benefit both participants – fungus + algae = lichen]	benefited	benefited
Mutualism = obligate symbiosis [both participants benefit, but this interaction is essential to the survival or reproduction of both participant – pollination of some flowers by insects, birds, or bats; termites and internal protozoa]	benefited	benefited

Most obvious are Predation and Competition - antagonistic relationships

2. Limiting factors: critical limiting factor and tolerance limits

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