Encyclopedia of Biology

cotyledons Leaflike structures (seed leaves) pro- duced by the embryo of flowering plants, the dicots (Magnoliopsida), and the m ...

self-taught. On September 11, 1848, he married Isabel- la MacDonald, daughter of John MacDonald. Croll started his career as a c ...

and “What Determines Molecular Motion? The Funda- mental Problem of Nature” (1872). A famous debate on the nature of deep-sea ci ...

cybernetics The science that studies the methods to control behavior and communication in animals (and machines). cyclic AMP (cA ...

two daughter cells by way of a constriction and drawing in of an actin/myosin ring around the center ofthe cell. cytoplasm The p ...

Dale, Henry Hallett(1875–1968) British Physiolo- gist Sir Henry Hallett Dale was born in London on June 9, 1875, to Charles Jame ...

degree in chemistry in 1920. The same year he was appointed assistant instructor in chemistry at the School of Agriculture and V ...

dehydration reaction(condensation reaction) A chemical reaction in which two organic molecules become linked to each via COVALEN ...

ofother neurons and transmits nerve impulses toward the cell body. A dendrite is also a branch or treelike figure produced on or ...

deoxyribose A five-carbon sugar (C 5 H 10 O 4 ) compo- nent of DNA. Joins with a phosphate group and base toform a deoxyribose n ...

of a secondary plant body, a periderm consisting of cork that serves as a protective packed-cell arrange- ment for woody stems. ...

food web. A detrivore is any organism that obtains most of its nutrients from detritus. deuterostomes One of the two groups of c ...

diatoms SeeALGAE;CHROMISTA. dichotomous Either halving or branching by pairs. dicot(dicotyledon) Amember of a subclass of the an ...

dimorphism The ability of a species to have more than one color or body form, such as differences between sexes. See alsoSEXUAL ...

dismutation SeeDISPROPORTIONATION. dispersion The distribution pattern, or spacing apart, ofindividuals from each other within g ...

docking studies Molecular modeling studies aiming at finding a proper fit between a ligand and its binding site. dodo A large an ...

in1936–39. For his work on vitamin K, Doisy was awarded the Nobel Prize in physiology or medicine for 1943. Later, Doisy improve ...

the italicized symbol(s) for the atom or atoms through which attachment to the metal occurs. double-blind study A clinical study ...

where one of the parents has chromosome 14 and 21 merge. Approximately 4,000 children with a Down’s syn- drome are born in the U ...

aseither large (e.g., Komodo dragon weighs up to 365 pounds) or small (e.g., Island fox in the Channel Islands). Island animal p ...