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Glossary: G is for ... gene, global warming, gymnosperm.
by Ariadne Unst

Glossary of G...

Gaia Hypothesis
For most practical purposes, the Earth may be regarded as a single living organism. Its surface is part of life itself.
Its inhabitants (trees, animals, viruses, etc.) may be viewed as the organs of the organism.
Proposed by James Lovelock.
Less controversially: (1) life depends on the physical world and (2) the physical world is influenced by living organisms.

Abnormal growth on a plant produced by irritation or injury.

gamete (n.)
A haploid reproductive cell.

gene (n.)
The smallest transmittable unit of genetic material consistently associated with a single primary genetic effect.

gene pool (n.)
All of the genes found in the individuals of the population of a particular species.

genet (n.)
A single sexually produced individual.

genotype (n.)
A specific combination of genes that determines a character.

genus (n.)
A group of plants or animals below a family and above a species.
A group of related species.
In the scientific designation for an organism, the genus name is capitalized and immediately precedes the species name.
From Latin for "race" or "kind."

geology (n.)
The study of the rocks of the Earth's crust.

geometric growth (n.)
Growth where the change in size or quantity (per unit of time) is some fraction of the previous size or quantity; specifically it dependends on population size. Also called exponential growth. Contrast with arithmetic growth.

germination (n.)
The start of vegetative growth of a plant from a seed.

germinative capacity (n.)
Percentage of seeds that germinate during the normal period of germination.

germ plasm (n.)
The part of the protoplasm that contains the chromosomes and genes. Within an individual or group, the collective materials that are the physical basis for inheritance.

glabrous (adj.)
Having a surface without hair or down.

glade (n.)
An open space in a forest.

Whitened with a bloom.

global warming (n.)
World-wide rise in temperature.
Measured as 1ºC in the 20th century.

grassland (n.)
An ecosystem dominated by species of grass. (Found where average precipitation is insufficient to support growth of shrublands or forest.) "Grass evolved relatively late, probably in Eocene times, about sixty million years ago" [ Jane Scott].

greenhouse gasses (n.)
Carbon dioxide, methane and other gasses whose increased presence in the world's atmosphere causes long-wave radiation (heat) from the earth's surface to be retained in the atmosphere more than previously. It appears that this is leading to global warming.

ground water (n.)
Water that has sunk into the ground where it flows slowly through the aquifer.

guild (n.)
A group of species that is competing for resources.

gynoecium (n.)
The female home of the flower consisting of one or more pistils. The apex (stigma) exudes a sticky liquid to which pollen sticks. The enlarged base (ovary) contains chambers which produce between a single and several thousands female gametes. The narrow portion between them (missing in some flowers) is the style.
Inside the carolla (of sepals) and the calyx (of petals) and the androecium (of stamens).

gymnosperm (n.)
[From Latin, "naked seed"]. A plant with exposed seeds, such as in conifers whose seeds develop in cones. Rocks dated at 350 million years old have been found to contain fossil gymnosperm. Compare with angiosperm.