Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
otvety_po_ekologii_i_ust_2012 (2).docx
Скачиваний:
1
Добавлен:
01.07.2025
Размер:
124.04 Кб
Скачать

Variant – 21

  1. Rate of a growth population

Rate of a growth community is a change of the community number in unit of time. Rate of a growth community can be positive, zero and negative. It depends on parameters of birth rate, death rate and migration (immigrations and emigrations). The rise (profit) of number occurs in the result of the birth rate and immigration of species, and reduction (loss) of number is in the result of the death rate and emigration of species.

There are absolute and specific growth rates of community.

Absolute (general) growth rate is expressed by the relation:

dN/dt,

where dN is a change of the community number for a time interval dt.

Specific growth rate is a relation of growth rate to initial number (N):

dN/(Ndt).

In the absence of limiting factors of environment specific growth rate is equal to size r which characterizing properties of the community and it is called specific (congenital) growth rate of the community or biotic potential of a kind:

r == dN/(Ndt) или dN/dt = rN.

  1. Commensalism and Amensalism

Types of communications and mutual relations between organisms

Alive organisms are definitely connected to each other.

Types of relations between organisms. Influence of one species on another can be positive, negative and neutral. Thus different combinations of types of influence are possible. There are neutralism, mutualism, commensalism, predatoriness, parasitism, a competition, amensalism.

Commensalism

A symbiotic relationship in which one organism derives benefit while causing little or no harm to the other.

Amensalism

Definition of Amensalism : between two species involves one impeding or restricting the success of the other without being affected positively or negatively by the presence of the other. It is a type of symbiosis. Usually this occurs when one organism exudes a chemical compound as part of its normal metabolism that is detrimental to another organism.<br><br> The bread mold Penicillium is a common example of this; penicillium secrete penicillin, a chemical that kills bacteria. A second example is the black walnut tree, which secrete juglone, a chemical that harms or kills some species of neighboring plants, from its roots.

A symbiotic relationship in which one organism is harmed or inhibited and the other is unaffected.

  1. Global Warming

Global warming refers to an unequivocal and continuing rise in the average temperature of Earth's climate system. Since 1971, 90% of the warming has occurred in the oceans. Despite the oceans' dominant role in energy storage, the term "global warming" is also used to refer to increases in average temperature of the air and sea at Earth's surface. Since the early 20th century, the global air and sea surface temperature has increased about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980. Each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850.

Future climate change and associated impacts will vary from region to region around the globe. The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well as a probable expansion of subtropical deserts. Warming is expected to be strongest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice. Other likely effects of the warming include more frequent extreme weather events including heat waves, droughts and heavy rainfall; ocean acidification; and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and the loss of habitat from inundation.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]