Modes of nutrition
What is the difference between autotrophs and heterotrophs?
Autotrophs synthesize their own organic molecules (food) whereas heterotrophs obtain organic molecules (food) from other organisms
All food chains start with...
All food chains start with a producer
The energy is transferred from producers to....
primary consumers
How many stages does a typical food chain (like the one shown in the guide) have?
Three stages.
What is a community?
A community is a group of populations living together and interacting with each other in an area.
Classify the following organisms according to their modes of nutrition (be as specific as possible): Galapagos Hawk, Passionflower, Bread mould.
Galapagos Hawk: Heterotroph, consumer.
Passionflower: Autotroph, producer.
Bread mould: Heterotroph, saprotroph.
Give three examples of producers...
Oak trees, maize plants, lagae, blue-green bacteria (cyanobacteria).
Do primary consumers absorb all of the energy in the food that they eat?
No, part of the energy is lost
Describe the first stage of the food chain shown in the guide.
1. Producers convert light energy into chemical energy of sugars and other organic compounds. This energy trapped by the producers eventually leaves them in one of three ways..
What are trophic relationships?
Trophic relationships involve one population of organisms feeding from another population.
What is the difference between saprotrophs and detritivores? give examples of both types or organisms.
Saprotrophs live on or in dead organic matter, secreting enzymes into it and absorbing the products of digestion. Example: Mushrooms, Bread mould.
Detritivores: ingest dead organic matter. Example: dung bettles and earthworms.
In almost all communities, the producers make organic matter by photosynthesis...What is the name of the other process used by producers to make organic matter? (check your notebooks)
Chemosynthesis
Heterotrophs are classified into four main groups according to their feeding pattern... three groups are included in the "energy flow through consumers" diagram... which group wasn't included? (check your notebooks)
Scavengers
Describe the second stage of the food chain shown in the guide.
Primary consumers eat producers and so obtain energy from them. The energy that they do not take into their tissues leaves them in one of three ways...
What is a trophic level? give three examples of trophic levels.
A trophic level is the position of an organism in the food chain.
Examples of trophic levels: producer, primary consumer, secondary consumer.
Is an organism that synthesizes its own organic molecules from simple organic substances an autotroph? why or why not? give an example.
It is not an autotroph because autotrophs synthesize their own organic molecules from simple inorganic substances, not organic but inorganic substances. For example plants synthesize glucose (C6H12O6), an organic molecule, from water (H20) and carbon dioxide (CO2), two inorganic compounds (pure substances).
What are the three ways in which energy leaves producers? (look at the flow chart)
1. Cell respiration.
2. Death of a producer without being eaten by a consumer.
3. Death of a producer because of being eaten by a consumer.
What are the three ways in which energy leaves consumers? (look at the flow chart)
1. Undigested organic matter (feces)
2. Cell respiration
3. Death of a consumer
Describe the third stage of the food chain shown in the guide.
Secondary consumers eat primary consumers and so obtain energy from them. The energy they do not take into their tissues leaves then in one of three ways...
What is the difference between a food chain and a food web?
A food chain shows only some of the trophic relationships in a community.
The complex network of trophic relationships in a community is shown in full in a complex diagram called food web.
Toenail fungus (tinea unguium), nematodes and tapeworms have something in common, they are parasitic, heterotrophic organisms that are not included in most food webs....
Explain reasonably why parasites tend to be excluded from most food webs.
Size-based trophic cascades do not allow for the presence of parasites in food web models because parasites are smaller than their food (hosts) and their incorporation into food web models generates loop errors.
Photosynthesis is a chemical process by which plants make their own food using energy from the sun.
The glucose produced in photosynthesis travels through the plant in the form of soluble sugars and provides energy to plant cells during respiration.
Plants respire at all times of the day and night because their cells need a constant source of energy to stay alive. The result of cellular respiration is that the plant absorbs glucose and oxygen, releases carbon dioxide and water, and releases energy. This energy is responsible for the plant's growth and other metabolic processes necessary for its survival.
According to this paragraph, why is energy released during cellular respiration? when does cellular respiration take place: during the day or at night?
Energy is released during cell respiration because autotrophs need this energy for growth and other metabolic processes necessary for their survival.
Cellular respiration takes place at all times (day and night).
Indicate a similarity and a difference between the energy flow through producers and consumers
-Energy flow through producers starts with light being the initial energy source, whereas energy flow through consumers starts with energy in organic matter eaten by primary consumers as the initial energy source.
-Both describe cell respiration as a source of energy loss.
Do heterotrophs or autotrophs lose more energy because of cell respiration? explain your answer.
Heterotrophs lose more energy because of cell respiration since they need energy to move in order to get their food, whereas autotrophs don't.
What trophic level do dung beetles, earthworms, bread mould and mushrooms belong to?
What happens to the energy that passes to these organisms?
Detritivores and saprotrophs.
The energy that passes to detritivores and saprotrophs is eventually released by cell respiration and lost as heat.