zoo-, zoa-, zo-, -zoic, -zoid, -zoite, -zoal, -zonal, -zooid, -zoon, -zoa, -zoan +

Attracted more or less equally to humans and to some other kinds of animal host; said, for example, of certain kinds of mosquitoes.

1. Living in the earliest geological era.
2. The time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms were the earliest forms of life.
3. Formed in the earlier of two divisions of the Precambrian era.
4. Noting or pertaining to the earlier half of the Precambrian Era, from about 5 billion to 2.5 billion years ago, during which the earliest datable rocks were formed and from which the oldest known fossil forms, blue-green algae and bacteria, have been recovered.

One of the individual members of a compound ascidian which are members of the Ascidiacea: sea-squirts or sedentary tunicates, either solitary or in colonies, having a degenerate nervous system, an atrium opening dorsally near the mouth and numerous gill-slits forming a basket-work. The whole organism is enclosed in a test or outer skin made of material resembling cellulose.

An independent polyp capable of feeding itself.

A polyp is described as a cylindrical organism with a thin body-wall consisting of two single layers of cells, the ectoderm and the endoderm separated by a gelatinous noncellular layer or mesogloea.

At one end there may be a mouth which is usually surrounded by tentacles. Polyps may be single (e.g, Hydra) or colonial (e.g. the coral-forming organisms). The latter are formed by repeatd budding from a parent polyp.

In such colonies a tube or coenosarc links the body-cavities of all the individuals with one another. There may be many different kinds of polyp in a colony, each specialized for some different function; such as, feeding, reproduction, protecting, etc.

1. Devoid of living organisms.
2. Without life; specifically, designating or of the Early Precambrian (Archean) era, before life appeared on earth.
3. Non living; without life.

The scientific study of inanimate nature.

Absence of living spermatozoa in the semen.

Moss animals.

Animals that attach themselves to hard substrates or algae in marine, brackish, and freshwater.

Belonging to the most recent division of geological time, including the tertiary, or "Age of Mammals", and the Quaternary, or "Age of Man".

Noting or pertaining to the present era, beginning 65 million years ago and characterized by the ascendancy of mammals.

1. Of, relating to, or being within any of the cavities of the body.
2. Inhabiting any of the cavities of the body; applied to certain parasitic protozoa, chiefly gregarines (order of Protozoa, allied to the Rhizopoda, and parasitic in other animals, as in the earthworm, lobster, etc.).

1. The youngest, or most recent, of the eras or major subdivisions of geologic time; extending from the end of the Mesozoic Era to the present.
2. The most recent era of geologic time, beginning about 65 million years ago, during which modern plants and animals evolved.

In biology, a reference to some plants that protect themselves from herbivorous animals by the production of noxious chemical substances (allelochemics).

1. Protozoa that can be cultivated in fecal matter, but do not necessarily live in feces within the intestine.
2. Protozoa which are found in fecal matter outside the body, but which do not inhabit the intestine.