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
1
Biological systems. Ecology as the science of biological systems
Textbook: pp. 4–8
GoalExplain the concept of a biological system and the hierarchy of levels of life, and list the tasks of ecology as a science.
New words
biological system (biosystem) · biologik sistema (biosistema)hierarchy · iyerarxiyaecology · ekologiyabiosphere · biosfera
Explanation
A biological system is a living whole made of interacting parts that can regulate itself and adapt to its environment: a cell, an organism and a forest all qualify. The levels of life form a hierarchy: molecule → cell → tissue → organ → organism → population → biogeocenosis (ecosystem) → biosphere, and each higher level contains the lower ones. A higher level has emergent properties that lower levels lack: a single fox does not form a food chain, but a population and a community do. The term ecology was introduced in 1866 by E. Haeckel (oikos – house, logos – science); it studies how organisms relate to one another and to their environment. Today ecology also covers populations, communities, ecosystems and the biosphere. Its tasks include finding the laws of how factors act, developing rational use of resources, creating biological pest control and waste-free technologies, keeping ecosystems stable and building an ecological culture.
Worked examples
A single stingray on the sea floor (organism) → a group of stingrays (population) → a community of fish, algae and plankton (biocenosis) → this community together with water, light and temperature (ecosystem) → all living layers of Earth (biosphere). Each next level contains the previous one.
A camel-thorn root takes up water from the soil: organ level; the vacuole of its cells holds water: cell level; camel-thorn plants form the plant cover of a whole desert: population/community level. One phenomenon can be viewed at different levels.
Class activity
Prepare 8 cards in class (molecule … biosphere). In pairs, arrange them in the right order, give one example of your own for each level and name the science that studies it (cytology, histology, ecology, etc.). When observing in the schoolyard, do not touch unfamiliar plants or mushrooms.
Practice
1
Define a biological system in your own words.
A living whole of interacting parts that can regulate itself and adapt to its environment.
2
Arrange from smallest to largest: biosphere, organism, tissue, population, cell, organ, ecosystem.
Cell → tissue → organ → organism → population → ecosystem → biosphere.
3
To which levels do «birch leaves» and «a birch forest» belong?
Leaves – organ level; a birch forest – biogeocenosis (ecosystem) level.
4
Why is it wrong to understand ecology only as «protecting nature»?
Ecology is first of all a science that studies the laws of relations between organisms and environment; nature protection is a practical task built on that knowledge.