(Upload on June 2 2023) [ 日本語 | English ]

Ecology (生態学)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

A model should be as simple as possible. But no simpler. (Einstein)
The derivation of word 'ecology'
Ecology (Oecology, Oekologie) = Eco + logy = Oikos (=household or at home) + Logos (logics)
Cf. economy: Ecology surveys energy flow and economics surveys money flow; viz. "Economics" deals with functional housekeeping, and "Ecology" deals with environmental housekeeping.
The totality or pattern of relations between organisms and their environment
If there are 100 ecologists, there are 100 kinds of definitions.
  1. The study of life on organisms (= environmental biology)
  2. General physiology about all organisms (narrow sense)
  3. The science of population (Clements)
  4. The scientific natural history - science of living things' economy and society (Elton 1927)
  5. The science dealing with the structure of nature or ecosystem, and Its relation to other sciences and its relevance to human civilization (Odum 1971)
  6. Study of the inter-relationships between organisms and their environments (Pianka 1978)

Classification (分類)

Principles and concepts pertaining to the ecosystem

Scale or level

Synecology: Community ecology, ecosystem ecology, production ecology, etc.
Autoecology: Population ecology, genecology, sociobiology, etc.


Animal ecology, plant ecology, fungal ecology, bacterial ecology, etc.

Study area

Ocean ecology, terrestrial ecology, alpine ecology, wetland ecology, etc.
[Lectures: environmental conservation, environmental sicences, HUSTEP]

Hierarchy (階層)

The focus of ecology is on the levels of organization from organisms to ecosystems (or nature).
Table. Levels of organization spectrum. Ecology focuses on the top-and portion of the spectrum; viz. the levels of organization from organisms to ecosystems (modified from Odum 1971 & Krebs 2000). Any more level aids in the study of another level, but never completely explains the phenomena occurring at that level.
    ⇓ nature                 ⇔ ⇅                           ⇑
    ⇓ landscapes             ⇔ ⇅                           ⇑
    ⇓ ecosystems (biosystem) ⇔ ⇅     ecosystem (biosystem) ⇑
    ⇓ communities (biome)    ⇔ ⇅                           ⇑
    ⇓ species                   ⇅                           ⇑
    ⇓ populations            ⇔ ⇅ energy  population system ⇑
    ⇓ organisms (individual) ⇔ ⇅         organismic system ⇑	
    ⇓ organs                 ⇔ ⇅         organ system      ⇑
    ⇓ cells                  ⇔ ⇅         cell system       ⇑
    ⇓ subcellular organelles ⇔ ⇅                           ⇑
    ⇓ genes                  ⇔ ⇅ matter  genetic system    ⇑
    ⇓ molecules              ⇔ ⇅                           ⇑

Animal ecology (動物生態学)

A study of the relationships of animals to their environments
Estimation of population density (個体数推定)

Territory (縄張り)

Any defended area by an organism or a group of similar organisms (Noble 1939)

Purposes: mating, nesting, roosting, feeding, edt.

Home range (s.s., 行動圏)
not associated with aggressive behaviour, as seen in territory (parts of the home range may be defended)

Group (群れ)

Summary as general use:
Herd: a group of herbivorous animals in a species living and feeding together

Ex. Elephants, deer and moose, giraffes (also used tower), hippo, whales, antelope. Sea urchins

Pride: lions, peacoks (also used muster and ostentation)
Pack: dogs, including coyotes, wolves and hounds, weasels

Clowder: cats (kindle for kittens) - not so common

Litter: kittens, uppies and pigles (at one time)

Troop: monkeys, apes
Flock: brids, including geese. livestock such as goats and sheep

Murder: crows and ravens.   Parliament: owls.   Gang: turkeys.
Flight: swallows.   Gaggle: geese.

Pod: dolphins, whales, pelicans, seals, walruses
Army: frogs, ants
School (shoal): fish
Herd behavior: the behavior of individuals in a group acting collectively without centralized direction ☛ Economics

Hierarchy (順位)


Ecochemicals (生態相関物質)

1959 Butenandt AFJ (1903-1995): C16H30O extracted from Bombyx mori

CH3(CH2)2CH=CHCH=CH(CH2)8CH2OH, named bombykol →
firstly-discovered sexual pheromone

Urban ecology (都市生態学)

Structure and dynamics of urban environments

urban ecosystem - bioecological approach
urbanization(some impact) - bad case: self-domestication
→ indicator of urbanization → consider the merit and demerit of urban