C4.2 Transfer of energy and matter Flashcards
What is an ecosystem composed of?
An ecosystem is composed of all the organisms in an area together with their abiotic environment.
What is a system? (in biology)
A system is a set of interacting or independent components.
What are the two types of systems?
- Open system
- Closed system
What is an open system?
Open system: where energy can enter or exist, but chemical resources cannot be removed or replaced.
What is a closed system?
Closed system: where energy cannot enter or exit, but chemical resources cannot be removed or replaced.
What is the initial source of energy in an ecosystem?
Sun light is the initial source of energy that sustains most ecosystems, as it is needed to produce glucose in photosynthesis.
What organisms use light as an energy source?
Plants, eukaryotic algae and cyanobacteria carry out photosynthesis and are referred to as producers or autotrophs.
What are heterotrophs?
Heterotrophs use the sunlight indirectly and are therefore still dependent on it.
How are organisms supplied with energy when they in a cave?
Organism must be adapted to life in a cave. Streams entering the cave bring dead organic matter which supplies a source of energy. Some caves (e.g. Movile Cave in Romania) do not receive any influx. energy is produced by archaebacteria through chemical reactions with sulphides, methane or other as substrates.
How are organisms supplied with energy when they in a deep sea?
In marine and freshwater ecosystems light must pass through water to reach producers. Transmission is not 100% and only shorter wavelengths will penetrate further in pure water which is why the sea often appears blue. The source of energy in deep sea often originates from bacteria which can use sulphides as a source of energy.
What is the flow of chemical energy through food chains?
Energy enters as light, flows as nutrients through the food chains and usually leaves as heat.
How are nutrients recycled in food chains?
Nutrients can cycle through successive food chains of consumers, decomposers and autotrophs. E.g. recycled nutrients include carbon, nitrogen and phosphorus.
What is the recycling of nutrients a good example of?
The recycling of nutrients is a good example of an interaction between biotic and abiotic factors within an environment. Nutrients are absorbed from the environment, used by living organisms and then returned to the environment. This process can be conceptualized as a cycle.
What is the purpose of a food chain?
A food chain shows the flow of energy through a sequence of organism, each of which feeds on the previous one. (arrows indicate direction of energy flow)
What are the different levels (trophic [feeding] level) of food chain?
- Primary producers
- Primary consumers
- Secondary consumers
- Tertiary consumers
- Quaternary consumers
How do producers obtain energy?
Most producers absorb sunlight using chlorophyll and other photosynthetic pigments. The light energy is converted to chemical energy, which is used to make carbohydrates, lipids and all the other carbon compounds that are required.
How do consumer obtain energy?
Consumers obtain energy from the carbon compounds in the organisms on which they feed. Primary consumers feed on producers (=herbivores); secondary consumers feed on primary consumers (=carnivores); tertiary consumers feed on secondary consumers, and so on. No consumers feed on the last organism in a food chain.
How do decomposers feature in a food chain?
Decomposers, fungi and many bacteria, obtain their energy and raw materials from the waste (e.g. faeces) and remains (e.g. dead bodies) of other organisms.
What does a food web represent?
A food web represents the complexity of trophic (feeding) relationships by showing interacting and interconnecting food chains and the many consumers there are.
How are decomposers supplied with energy?
Decomposers are supplied with energy from carbon compounds in dead organic matter such as faeces, shed exoskeletons of an insect or reptile, dead plant material such as fallen leaves.
How do some decomposers obtain their energy?
Decomposers such as saprotrophs secrete digestive enzymes into dead organic matter and digest it externally by absorbing the products of digestion such as sugars and amino acids.
How do saprotrophs break down complex insoluble carbon compounds?
Saprotrophs also break down complex insoluble carbon compounds into soluble ones, and by doing so recycling dead matter which otherwise would build up over the years. Decomposers are the waste disposers and recyclers.
What is an autotrophs?
Autotrophs= organisms that use external energy sources to synthesize organic compounds from inorganic substances (CO2, HCO3- as carbon sources). Energy in the form of sunlight is required for carbon fixation and for building macromolecules.
What is an heterotrophs?
Heterotrophs = synthesize organic compounds by taking in and digesting carbon compounds