BIOSPHERE: Life supporting zone where the 3 zones meet, interact & make life possible
Lower atmosphere - found to contain windblown organisms, seeds, and spores.
BIOTIC or living components include plants, fungi, animals and microbes living on Earth.
Constant interaction between the abiotic & biotic components of the biosphere results in the transfer of food and energy, making it a stable and dynamic SYSTEM.
A population is a group of living organisms of the same kind living in the same place at the same time.
All of the populations in the same habitat interact and form a community.
A niche is the role and position of an organism (species) in the community. No two species can occupy exactly the same niche.
The community of living things interacts with the non-living world around it to form the ecosystem.
Ecosystems is a complex interaction of living and non-living processes e.g. as small as a puddle or as huge as the Earth.
Habitats that have similar climate and plants are called biomes.
------------------------------------ACTIVITY------------------------------------
PROCEDURE:
- Locate a small patch of land to examine.
- Use a string to form a circle to mark our study area.
- Record observations about your ecosystem. Include all living and non-living things.
- Record temperatures and other abiotic factors in your ecosystem.
- Turn over a small patch of the turf or vegetation. Observe what's beneath the surface. Replace whatever vegetation you have dug to the original state.
DISCUSSION:
- Consider the variety of living and non-living things in your ecosystem. Which was the largest population?
- How are the survival needs being met in your ecosystem? Air? Food? Water? Sunlight?
---------------------------------------------------------------------------------
Living things cannot exist alone, there must be a relationship between them. Living things are adapted to the environment where they live.
ECOLOGY is the study of how living things interact with each other and with their environment.
ECOSYSTEM consists of a community of living organisms interacting with each other and their environment to form a self-sustaining unit. The environment consists of non-living (abiotic) part and living (biotic) part.
Factors of that affect the ecosystem:
Light
- Affects many living organisms, not just plants.
Temperature
- Affects physiological activities of all living organisms
Water
- Essential for life
- Organisms may have specially adapted features for survival in places with a lot of or very little water.
Oxygen
- Most organisms are aerobes.
Salinity
- Important factor for aquatic organisms
- Also a factor for other organisms
pH
- May be influenced by photosynthetic activity of aquatic plants (freshwater)
Acids pH : 1 - 6.9
Alkali pH : 7.1 - 14.0
Water (neutral) : pH 7.0
--------------------BIOTIC FACTORS----------------------
1. Symbiosis
- a long-term relationship between two different species "living together". The relationship varies in population, can be mutualism, commensalism & parasitism.
Mutualism
- Each population benefits. The interaction is necessary for the survival and growth of each species
+ / + relationship
Commensalism
- One population benefit; the other is unaffected
+ / O relationship
Parasitism
- One population benefits (parasite) while the other is harmed (host). The interaction is necessary for the survival of the parasite.
+ / - relationship
2. Competition
- Both population compete with each other for limited resources in the same ecosystem; both species are adversely affected by the relationship.
Interspecific (a form of symbiosis) or
Intraspecific (same species) competition
- / - relationship
3. Predation
- One population feeds on the other. The interaction is necessary for the survival of the predator.
+ / - relationship
FOOD CHAIN
- A series of organisms through which energy is transferred in material form.
- Carbon compounds move through the flood chains.
- All the energy in an ecosystem comes from the SUN.
By studying food chain, we can follow the basic mechanism of transfer of food energy and nutrients through various components of nature.
Food chain helps us understand the movement of toxic substances in an ecosystem and the problems of their biological transfer of food along with toxins substances.
- Energy flows in one-direction (non-cyclical) and it is either utilised or lost into the surroundings but cannot be recycled.
Unidirectional flow of energy
- The amount of available energy in food web decreases with each successive leve.
Food consumed = growth + respiration + heat + egesta (faeces) + excreta (urine)
Only about 10% of the energy is stored as new tissues and is available for transfer to next feeding level.
90% of the energy is lost because some food may not be eaten, or passes through the body without being digested and a lot of the energy is used in respiration.
The shorter the food chain, the greater is the available food energy.
Decomposers are detritivores that recycle organic matter back to inorganic nutrients (carbon, nitrates) in ecosystems. E.g. fungi, bacteria
Detritus feeder acquire nutrients from dead animals/plants or animal waste products. E.g. certain beetles, earthworm, termites, bacteria, fungi.
Cycling of Nutrients in an Ecosystem
Carbon Cycle and Nitrogen Cycle
Ecological Pyramids
- Pyramids of numbers
- indicate the relative numbers of individuals at each level
- the dry mass of all the organisms at each trophic level may be estimated
- the total energy utilized at each trophic level
- atmospheric CO2 is 0.03% (main source) important component of all living organisms.
- only plants can take in CO2 & convert it to organic compounds
- carbon compounds move through the food chains
- CO2 is returned to the atmosphere through respiration decay activities also release CO2
- Carbon may be trapped in limestone and fossil fuels
No comments:
Post a Comment