1. The right answer is B
In ecology, the biotic factors represent all the interactions of the living on the living in an ecosystem. Opposable to abiotic factors, they constitute a part of the ecological factors of this ecosystem. These are food resources, trophic predation, cooperation, competition, parasitism, etc.
2. The right answer is C.
A keystone species is a species that has a disproportionate effect on its environment in terms of numbers or biomass.
Some species affect many other organisms in an ecosystem.
When a keystone species disappears, an ecosystem can be significantly degraded and possibly relatively fast, making it a species of heritage interest. It is not necessarily a large species, or a species with significant numbers or productivity, but a species that structures its ecosystem or ensures its ecological balance.
3. The right answer is C
The competition exists when:
* Individuals of the same species or different species, search for and exploit the same resource present in limited quantities
* The resources are not limited but the competing organisms are harming (a shelter, a nesting site ...)
4. The right answer is B.
Biomass is the total mass of living matter present at a given trophic level in an ecosystem. It can also relate to a given population in a community. Biological productivity is the increase, the accumulation of biomass according to a given time. A productive ecosystem is not necessarily rich in biomass. Note that the higher the trophic levels, the lower the number of individuals and the biomass. There is, for example, a lot more phytoplankton than big predators like the shark in the oceans. The presence of species at the top of the food web is generally a sign of good health of the ecosystem: for simplicity, the ecosystem is quite productive for ensure the survival of the most resource-intensive species.
5. The right answer is B.
(The rest is used for metabolic processes or lost as heat. )
In an ecosystem, a light energy flow ensures primary production in chlorophyll plants. These are the food source available to herbivorous consumers (themselves a nutritional resource for carnivores). There is therefore a circulation of organic matter which, starting from the green plants, crosses the consecutive links of the ecosystem. This organic material is potential chemical energy that is transferred from producers to consumers.
Because of the nutritional loss that occurs at each stage of consumption, the energy flow gradually decreases, and this is why we often represent the network of ecosystem transfers in the form of a pyramid, whose base corresponds to the producers and the eventual super-predator peak that is fed by one or more levels of consumers interposed between primary producers and him. This is to say the precarious situation of superpredation.
6. The right answer is B. consumer.
The term "heterotroph" refers to an organism that is unable to synthesize its own components and thus uses sources of exogenous organic matter. This mode of nutrition is characteristic of all living beings that are neither chlorophyllous plants, nor cyanobacteria, nor certain bacterial species capable of photosynthesis or chemosynthesis, these being autotrophic. In other words, animals, fungi, some plants, protozoa and most prokaryotes are heterotrophic.
7. The right answer is B.
A population with a population is a phenomenon where populations fluctuate (increase and decrease) over a predictable period of time.
Are keystone species. A number of factors influence demographic changes, such as food availability, predators, disease, and climate.
8. The right answer is B. Lichen.
Pioneer species is a forms of life that colonize or recolonize an ecological area.
Lichens are composites resulting from a symbiosis between at least one heterotrophic fungus called mycobiont, representing 90% of all, and microscopic cells with chlorophyll (green algae or cyanobacteria autotrophic for carbon) called "photobionts".
9. The right answer is A.
An industrial disaster is linked to an accident in one of the phases of industrial production, in the mining or during the transportation of this production, in particular the transport of oil, which caused many oil spills. The damage is persistent (nuclear radiation takes several years to disappear, there are still residues of black tides in the oceans that go asphixier aquatic fauna and flora, and the pollution has caused a permanent global warming ...).
10. The right answer is D.
The fox is a predator for chickens, it is also the most common in our campaigns. He has always been around poultry houses, hoping for easy processes. Because face to him, the chicks is hardly more likely to escape. It is not uncommon to find all the fowl devoured by the fox, even in the middle of the day.
