Bio Prelim Notes

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Bio Prelim Notes

Environment: It’s our surroundings or external factors and forces (conditions) that affect and organism or group of organisms.
Ecology: The study of interactions that take place between organisms and their environment.
Abiotic: Non-living factors
Biotic: Living factors
Ecosystem: Is an interaction between living and non-living factors in an environment.

Abiotic Factors
Biotic Factors
Soil Ph
Soil Humidity
Soil Temperature
Air Temperature
Population Density
Wind Speed
Sunlight intensity

Soil Nutrients

Factors determining the distribution and abundance of a species:

Abiotic factors
Water (availability) and ions concentration
Varies from deserts to swamps. Some soils are rich and others are poor
Readily available
Light intensity
Readily available
Intensity &wave length varies with the depth of water
Varies – depending on season and latitude/ altitude
Less variation in oceans, decreases with depth
Gases O2 & CO2
No shortage of gases, availability decreases with altitude
Oxygen availability is low and gas solubility decreases with an increase in temperature
Viscosity – density
Less than water
Buoyancy – floating
Little support from air
Supports body weight
Turbidity – cloudiness of water

Water pH affects efficiency of enzymes which control photosynthesis & respiration
Salinity (amount of salt) = less
Photosynthesis = fewer plants & animals

Quadrants: used to estimate the abundance of organisms in an area

Animal abundance = number of captured x number of recaptured divided by the number of tagged in recapture.

Difference between Aquatic and Terrestrial

Aquatic 65%
Terrestrial 35%
Lots of buoyancy in water. Dense. Supports organisms
No buoyancy
Temperature variation
Low variation
High variation range
Availability of Gases
Low: must rely on dissolved gases 0.5%
20% oxygen
Water ions
Higher via dissolved salts/ions
No ions unless dissolved or in solid salt form
Light penetration
Low: decreasing with depth
Very high: readily available
High: increasing with depth
Low: decreases with height
High viscosity
Low viscosity

Adaptation: An adaption is a feature or characteristics which helps the organism survive in its environment.
Structural – concerned with the anatomy of the organism (size, shape, appearance or parts of the body)
Physiological – involved with the internal functioning of the body’s metabolism
Behavioural – concerned with how an organism behaves

Example (animal): Echidna, spikes on its back for protection (structural), not nocturnal however they go out when its cooler in the day (behavioural), they lay 1 egg which hatches after 10 days (physiological).

Example (plant): Rainforest leaves, drip tips also grooved leaves, and this is to absorb as much sunlight as possible on the dark understory.

Ecological Pyramids
Diagram that shows the relative amount of energy or organisms contained within each trophic level of a food chain.

Cellular respiration: process that takes place in the cells during which energy is released and used by cells for activities.

Photosynthesis: biochemical process by which plants manufacture their food (glucose C6H12O6), it requires chlorophyll and sunlight to occur and takes place in the upper cuticle in the plastids.

Cell: smallest structural and functional unit of an organism, it is microscopic and consists of cytoplasm and a nucleus enclosed in a membrane.
Chemicals in cells include:
Chloride ions
Lignin (cellulose)

Cell theory
All living matter is made up of one or more cells
The chemical reactions of a living organism take place within cells
All cells are formed from pre-existing cells and these cells contain the hereditary info.

Carbon compounds include: organic compounds (carbon, hydrogen, oxygen + nitrogen, phosphorus), lipids, carbohydrates (glucose), proteins (amino