#ecology
170 materials
Ecology: Biology of Interaction. IV-06. Classification of Relationships Between Populations
The well-known American ecologist Eugene Odum proposed classifying relations between species (or populations) by their effects on one another. He distinguished three types of effects: positive (+), negative (−), and neutral (0). However, correctly defining positive and negative effects is …
Ecology: Biology of Interaction. IV-05. The Lotka-Volterra Model
In 1925, the well-known Italian mathematician Vito Volterra, while speaking over lunch with his future son-in-law (an ichthyologist), became interested in fish population dynamics. In particular, he learned that reduced fishing during World War I increased the share of predatory …
Ecology: Biology of Interaction. IV-04. Exponential and Logistic Population Growth
In the logistic model, the variable K is introduced: environmental carrying capacity, the equilibrium population size at which all available resources are consumed. Growth in the logistic model is described by dN/dt = r × N × (K−N)/K. For historical …
Ecology: the Science of Interactions. IV-03. Demographic Tables, Pyramids, and Survival Curves
Demographic tables provide material for constructing survival curves. Such a method of graphical representation of the dependence of the proportion of individuals remaining alive on their age was proposed by Robert Pearl in the 1920s. He distinguished three main types …
Ecology: Biology of Interaction. IV-02. Population Characteristics
Demographic characteristics of populations can be divided into two groups: static and dynamic. Static population characteristics (note: static, not statistical!) can be determined for a specific moment in time; an example is population size. Ho...
Ecology: Biology of Interactions. IV-01. Populations and Their Properties
The concept of «population» — is one of the most important in biology. As is the case with key terms, it is frequently used with different meanings. According to Troyan, three approaches to defining the concept of «population» are possible: …
Ecology: Biology of Interactions. III-11. Trophic Links and Levels
Autotrophs obtain biogenic elements and the necessary energy from the environment and create organic substances. The organic substances of autotrophs are consumed by some heterotrophs, these heterotrophs -- by others, and so on until the organic matter synthesized by autotrophs …
Ecology: Biology of Interactions. III-12. Ecological Efficiencies
The following measures of efficiency in energy consumption and processing can be distinguished: exploitation efficiency E1=Iexploiter/Pprey; assimilation efficiency E2=A/I; net production efficiency E3=P/A; gross production efficiency E4=P/I=E2×E3; ecological efficiency E5=Pexploiter/Ppre...
Ecology: The Biology of Interactions. III-14. (Supplement) School Problems on Ecological Pyramids
Did you know that hippopotamuses come ashore at night to graze? Apparently, in the imagination of the problem-book author and Wikipedia editors, frog tadpoles do something similar. Otherwise, these predominantly herbivorous aquatic larvae of tailless amphibians would be unable to …
Ecology: Biology of Interactions. III-13. Ecological Pyramids
Charles Elton proposed a way of graphically expressing relationships between trophic levels, which has become almost a symbol of ecology as a science. This refers to ecological pyramids. When constructing ecological pyramids, measures of abundance of representatives of different trophic …
Ecology: Biology of Interactions. III-15. (Supplement) Flora, Fauna, Consortia
Flora is the set of plant species associated with a given geographic space. Flora composition is determined both by present conditions and by geological history. Vegetation is the spatial organization of plant cover; fauna is the corresponding set of animal …
Ecology: Biology of Interactions. III-16. (Supplement) Ecosystem Efficiency and Energy Subsidies
Ecosystems can be supported by energy expenditures from outside. To prevent weeds from outcompeting wheat in a wheat field, humans add external energy inputs.
Ecology: Biology of Interactions. III-17. (Supplement) Biomes and Human Culture
Humans evolved as a species with extraordinarily plastic behaviour, capable of occupying diverse ecological niches. In very broad terms, the following types of traditional human lifestyles can be distinguished. Appropriative economy: hunting, fishing, gathering. This highly diverse mode of human …
Ecology: Biology of Interactions. III-10. Nature and Characteristics of Assemblages
{ "title": "", "summary": "", "body": "Probably, the group still represents a real ecological unit. The functioning of the group consists of the activity of its constituent individuals, but it is more than its sum. The efficiency of the group …
Ecology: Biology of Interactions. III-09. Trends in Successions
In a typical succession sequence (e.g., in an artificial microcosm or during colonization of a new habitat in primary autotrophic succession), fast-growing species dominate first, then are replaced by slower but more competitive species.
Ecology: biology of interactions. III-08. Succession. Basic concepts
The main cause of successions is the absence of equilibrium between production and respiration in the ecosystem, that is, an imbalance of ecological balance. This leads to a change in the stock of organic matter in the ecosystem and, ultimately, …
Ecology: Biology of Interactions. III-07. Productivity of Different Biomes
Net primary production of land per year — 110–120 billion tons of dry organic matter, and of the ocean — 50–60 billion tons. Approximately, one can say that the ocean provides about 1/3 of our planet's production while occupying approximately …
Ecology: Biology of Interactions. III-06. Ecosystem Production and Its Measurement
Biomass — the total mass of all organisms of the entire community or a separate population, measured in units of wet or dry mass per unit of area or volume of the environment. The biomass includes the bodies of organisms …
Ecology: Biology of Interactions. III-05. Ecological Balance
Since autotrophs and heterotrophs are inextricably linked, the most important characteristic of the biosphere is the ratio between their main functions: the creation and destruction of organic matter. This ratio is called the ecological balance. A fundamental property of the …
Ecology: Biology of Interactions. III-04. Classification of Biomes
A biome is a large type of biogeocenosis characterized by a similar nature of vegetation and occupying certain regions of the planet. Biomes are regulated by macroclimate and primarily by the amount of precipitation and temperature