Chapter 4 Flashcards
Energy sources used in biological systems
energy allows matter to combine into different complex structures. It is essential for systems to work and cannot be recycled, it must be supplied continuously.
What are the main sources of earths energy
Sun energy (radiant energy) and geothermal activity.
What is geothermal activity
heat generated from the earths core which escapes to generate geothermal activity on the earths surface and in the ocean
Abiotic factors of hot springs and geysers
lack of sunlight, extreme pressures, high temperatures and acidity. Organisms survive by using simple inorganic chemical compounds such as iron and sulfur as their source of matter and energy
What are autotrophs
an organism capable of making its own food from inorganic substances using light and chemical energy.
Another name for autotrophs
Producers, include Green plants, algae and certain bacteria.
How do producers transform the suns energy
through photosynthesis. Plant cells have specialised organelles that are called chloroplasts that contain chlorophyll. Chlorophyll can absorb most wavelengths of light (except green). Only 10% of the trapped light goes into bonds. Energy is released when bonds are broken.
What are heterotrophs
members of the community that cannot synthesise their own organic compounds from inorganic materials
What are two examples of glucose polymers and what do they do
Cellulose (used to build the cell wall), and starch (used as an energy store for plants during periods of reduced sunlight)
What is gross primary productivity
GPP is the total organic matter in an ecosystem made via photosynthesis
What is Net primary productivity
NPP is the amount of organic matter available to herbivores
How is NPP calculated
GPP - What the plants use themselves
Primary productivity in different ecosystems
Not all producers can make the same amount of plant mass. Temperature can affect the rate at which chemical reaction can occur. Production of organic materials from the glucose made in photosynthesises is greater in some seasons compared to others. Oceans primary producers is not as efficient as terrestrial ecosystems because light does not penetrate deep water and nutrients are not freely available.
What is photosynthetic efficiency
How well producers convert their energy during photosynthesis. This depends on the availability of raw materials and sunlight.
How do herbivores extract energy from producers
consumers cannot carry out photosynthesis and thus cannot make their own energy. All animals must obtain their energy from the food they eat. Herbivores consume large amounts of plant material. They extract energy from the plant bonds through a process called cellular respiration.
What is the use for energy in animals
To carry out work. Foraging for food, avoiding predators, long treks keeping warm. Bodily functions, building/repairing tissue and production of gametes in preproduction.
What are the levels in a generalised food chain
Sunlight – producer – primary consumers (herbivores) – secondary consumers (second order consumers) – tertiary consumers (third-order consumers) – top carnivore
What is the role of detritivores in an ecosystem
Feed on dead or decaying organic remains and waste
What are the three types of consumers
Primary consumers - herbivores, feed directly on producers (plants)
Secondary consumers - carnivores, feed on primary consumers (meat)
top consumers feed on secondary consumers.
What is trophic efficiency
The percentage of the energy at one trophic level that ends up at the next trophic level.
What is the 10% rule
Only 10% of the energy at one trophic level is passed onto the next level. The remaining 90% is lost to its surroundings as 80% heat and 10 % chemical energy waste.
what is a food chain
one organism occupying a trophic level is consumed by the next organism in a higher trophic level, creating a chain whereby energy and matter are passed to progressively higher levels
What is a food web
Food web is a diagram that shows how different organisms feed on each other, thereby transferring energy through an ecosystem; interconnecting food chains in an ecosystem.
Pyramid of number
Shows numbers of organisms at each level, usually a drop at each level and can be inverted. E.g. when one large producer supports lots of consumers
Pyramid of biomass
Total mass of organisms measured at each level. Can be at a particular time or over a year. Usually pyramid. e.g when photo synthesizers are small with short life span.
Pyramid of Energy
A representation that shows the rate at which energy is transferred from one trophic level to another in a given area of a ecosystem
How are nutrients returned to soil
Nutrients essential for plant growth are taken from the soil by a network of plant roots. Micro organisms in the soil and on the surface contribute to the decay of plant matter such as leaf litter. Nutrients also Exeter the soil in rainfall. An obstacle in the nutrient cycle is ow quickly nutrients can be returned to the soil from the decomposition of dead organic matter
Carbon cycle
Autotrophs take in carbon dioxide from the atmosphere and carbon dioxide is released through respiration and combustion. Remains of organisms for fossil fuels under high pressure and long periods of time.
What are carbon sources. Give 3 examples
the origin of materials deposited in the sink. emissions from burning fossil fuels, forest fires, and respiration.
What are carbon sinks. Name 3
a reservoir of material or energy. Eg, Ocean, plants and soil
Nitrogen cycle
Nitrogen is essential for living things to make proteins essential for plant structure and function. Nitrogen is converted to nitrates by specialised bacteria. Nitrogen is returned to atmosphere by volcanic activity and bacterial conversion of nitrates to nitrogen.
how do plants get nitrogen
Plants cannot absorb nitrogen directly from the atmosphere, most plants can only absorb the dissolved form of nitrates. Fixers, nitrifiers and denitrifies are specialised bacteria that live in root organs called nodules. In exchange plants have a ready source of nitrogen.
What is nitrogen fixation
Process when free nitrogen is fixed to form ammonium and nitrate ions so that living things can use it
What are ammonifiers and what do they convert
Bacteria and fungi, convert waste into ammonia
What are nitrifiers and what do they convert
Bacteria, convert ammonia into nitrites and nitrites into nitrates
What are denitrifiers and what do they convert
Bacteria, nitrates into nitrogen
What are nitrogen fixers and what do they convert
Nitrogen into ammonium ions
Phosphorus cycle
Phosphorus gets buried in rocks by volcanic activity and earthquakes. Weathering releases phosphates to soil and water entering the food chain through plants. Can be returned to abiotic reservoirs as calcium phosphates in bone, shells hard parts of aquatic animal.
Biological magnification
The concentration of non-biodegradable substances such as DDT and mercury can be increased as they get passed from one trophic level to the next on a food chain. May not affect organisms lower in the food chain but can be disastrous to the top of the food chain. For example, reproduction rates could decline and death rates could rise.
What is humus
the organic matter found in soil. Stores nutrients, contributes to soil texture and water holding capacity
what are the two criteria a region must meet to qualify as a biodiversity hotspot
Must have a high percentage of plant life found nowhere else on the planet.
It must have 30% or less of its original natural vegetation. (must be threatened)
human impact on nitrogen and phosphorus cycle
too much fertiliser in soil, soil cant absorb, water washes excess nutrients into river systems. algae use nutrients which leads to eutrophication
human impact on carbon cycle
Urbanisation, deforestation, Factory emissions, car emissions
