Microbiology and Immunology

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Marine microbiology

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The resistance to Margulis’ work in microbiology may

perhaps be explained by its implications for the more theoret-

ical aspects of evolutionary theory. Evolutionary theorists,

particularly in the English-speaking countries, have always

put a particular emphasis on the notion that competition for

scarce resources leads to the survival of the most well-adapted

representatives of a species by natural selection, favoring

adaptive genetic mutations. According to Margulis, natural

selection as traditionally defined cannot account for the “cre-

ative novelty” to be found in evolutionary history. She argues

instead that the primary mechanism driving biological change

is symbiosis, while competition plays a secondary role.

Margulis doesn’t limit her concept of symbiosis to the

origin of plant and animal cells. She subscribes to the Gaia

hypothesis first formulated by James E. Lovelock, British

inventor and chemist. The Gaia theory (named for the Greek

goddess of Earth) essentially states that all life, as well as the

oceans, the atmosphere, and Earth itself are parts of a single,

all-encompassing symbiosis and may fruitfully be considered

as elements of a single organism.

Margulis has authored more than one hundred and thirty

scientific articles and ten books, several of which are written

with her son Dorion. She has also served on more than two

dozen committees, including the American Association for the

Advancement of Science, the MacArthur Foundation

Fellowship Nominating Committee, and the editorial boards

of several scientific journals. Margulis is co-director of

NASA’s Planetary Biology Internship Program and, in 1983,

was elected to the National Academy of Sciences.

See alsoCell cycle (eukaryotic), genetic regulation of; Cell

cycle (prokaryotic), genetic regulation of; Evolution and evo-

lutionary mechanisms; Evolutionary origin of bacteria and

viruses; Microbial genetics; Microbial symbiosis

MMarine microbiologyARINE MICROBIOLOGY

Marine microbiology refers to the study of the microorgan-

ismsthat inhabit saltwater. Until the past two to three decades,

the oceans were regarded as being almost devoid of microor-

ganisms. Now, the importance of microorganisms such as bac-

teria to the ocean ecosystem and to life on Earth is

increasingly being recognized.

Microorganisms such as bacteria that live in the ocean

inhabit a harsh environment. Ocean temperatures are generally

very cold—approximately 37.4° F (about 3° C) on average—

and this temperature tends to remain the cold except in shal-

low areas. About 75% of the oceans of the world are below

Light microscopic view of marine plankton.

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