Lessons 1–2 · 2 lessons · A. G‘afurov, A. Abdukarimov, J. Tolipova, O. Ishankulov, M. Umaraliyeva, I. Abdurahmonova. Biology Grade 11, 1st edition. Sharq Publishing and Printing Joint-Stock Company, Tashkent, 2018
2
The development, branches and methods of ecology
Textbook: pp. 9–13
GoalDistinguish the stages of development, branches and research methods (field, experiment, modelling) of ecology.
The first ideas on how organisms relate to the environment appear in the works of ancient philosophers and of Eastern scholars such as al-Khwarizmi, Beruni, Ibn Sina and Babur. In the 19th century A. Humboldt studied how environmental factors act on plants, in 1866 Haeckel introduced the term ecology, in 1935 A. Tansley coined «ecosystem» and V. N. Sukachev developed the concept of the biogeocenosis. Ecology is divided by what it studies: autecology – a single organism and its environment; demecology – population numbers and structure; synecology – communities of different species; biogeocenology – ecosystems; global ecology – the biosphere. There are also applied branches: landscape, industrial, social and mathematical ecology. Methods fall into three groups: the field method (observing, counting and ringing birds in nature), the experimental method (changing one factor in the laboratory; an aquarium is a model of a freshwater body) and mathematical modelling (calculating system properties on a computer to predict future changes).
Worked examples
«The number of females in a colony of marmots on a mountain slope rose over two years» is a demecology question (population size). «How one marmot prepares for hibernation» – autecology. «The community of marmots, predators and grasses» – synecology.
A researcher wants to know how soil moisture affects plant growth. With the field method she records moisture together with other factors (temperature, light) acting jointly in a natural plot; with the experimental method she grows the same plant at equal temperature and light, changing only the amount of watering – so only the effect of moisture shows.
Class activity
Mark off 1 m² in the schoolyard or garden with string, count the plant species in it and note them down – a small example of the field method. Do not dig the soil or touch unfamiliar plants and insects; use tools only with your teacher.
Practice
1
What is the difference between autecology and synecology?
Autecology studies one organism and its environment; synecology studies a community of different species.
2
Which method does bird ringing belong to and why?
The field method: birds’ migration and numbers are followed in natural conditions.
3
Why is it hard to study one factor alone in nature?
Because all factors act together as a complex; therefore a model is built for experiments (for example, an aquarium).
4
State the contribution of Tansley and Sukachev to ecology.
Tansley introduced «ecosystem» in 1935; Sukachev developed the concept of the biogeocenosis.