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Porifera

(Encyclopedia)CE5 A. Canal systems of the three morphological types of sponges B. Internal anatomy of an asconoid sponge, representative of the phylum Porifera Porifera pōrĭfˈərə [key] [Lat.,=pore bearer],...

moss, in botany

(Encyclopedia)CE5 Life cycle of a moss: A germinating spore forms a transitory branching structure on the soil surface, which develops into the conspicuous gametophyte, the familiar moss plant. Eggs and sperm ar...

heredity

(Encyclopedia)heredity, transmission from generation to generation through the process of reproduction in plants and animals of factors which cause the offspring to resemble their parents. That like begets like has...

impotence

(Encyclopedia)impotence imˈpətəns [key], inhibited sexual excitement in a man during sexual activity that, despite an unaffected desire for sex, results in inability to attain or maintain a penile erection. Know...

sea star

(Encyclopedia)sea star, also called starfish, echinoderm of the class Asteroidae, common in tide pools. Sea stars vary in size from under 1⁄2 in. (1.3 cm) to over 3 ft (90 cm) in diameter. They are commonly dull ...

Nemertinea

(Encyclopedia)CE5 A. Ribbon worm, representative of the phylum Nemertinea B. Internal anatomy of a ribbon worm Nemertinea nĕmərtĭnˈēə [key], phylum of elongated, often flattened, marine Worms, sometimes c...

Brachiopoda

(Encyclopedia)CE5 Internal anatomy of a lamp shell, Magellania, representative of the phylum Brachiopoda Brachiopoda brākēŏpˈədə [key], phylum of shelled sessile or sedentary marine animals, commonly know...

reproduction

(Encyclopedia)CE5 Examples of asexual reproduction reproduction, capacity of all living systems to give rise to new systems similar to themselves. The term reproduction may refer to this power of self-duplicati...

adaptation

(Encyclopedia)adaptation, in biology, has several meanings. It can mean the adjustment of living matter to environmental conditions and to other living things either in an organism's lifetime (physiological adaptat...

gene

(Encyclopedia)gene, the structural unit of inheritance in living organisms. A gene is, in essence, a segment of DNA that has a particular purpose, i.e., that codes for (contains the chemical information necessary f...