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
