Life is studied at the atomic and molecular scale in molecular
biology, biochemistry, and molecular genetics. At the level of
the cell, it is studied in cell biology and at multicellular scales,
it is examined in physiology, anatomy, and histology. Developmental
biology studies life at the level of the development or ontogeny
of an individual organism.
Moving up the scale towards more than one organism, genetics considers
how heredity works between parent and offspring. Ethology considers
group behavior of more than one individual. Population genetics
looks at the level of an entire population, and systematics considers
the multi-species scale of lineages. Interdependent populations
and their habitats are examined in ecology and evolutionary biology.
A speculative new field is astrobiology (or xenobiology) which
examines the possibility of life beyond the Earth.
History of the Word Biology
Formed by combining the Greek bios, meaning 'life', and logos,
meaning ‘reasoned account’, the word "biology" in
its modern sense seems to have been introduced independently
by Gottfried Reinhold Treviranus (Biologie oder Philosophie der
lebenden Natur, 1802) and by Jean-Baptiste Lamarck (Hydrogéologie,
1802). The word itself is sometimes said to have been coined
in 1800 by Karl Friedrich Burdach, but it appears in the title
of Volume 3 of Michael Christoph Hanov's Philosophiae naturalis
sive physicae dogmaticae: Geologia, biologia, phytologia generalis
et dendrologia, published in 1766.