alternation of life phases
- , less correctly alternation of generations. Having distinct sporophytic (diploid), e.g. stems, roots, leaves, cones, etc., and gametophytic (haploid), e.g. tissue within the seeds of cycads and all other seed plants, phases in the life cycle.
Expanded glossary of Cycad terms . 2014.
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Alternation of generations — (also known as alternation of phases or metagenesis) is a term primarily used in describing the life cycle of plants (taken here to mean the Archaeplastida). A multicellular sporophyte, which is diploid with 2N paired chromosomes (i.e. N pairs),… … Wikipedia
alternation of generations — Biol. the alternation in an organism s life cycle of dissimilar reproductive forms, esp. the alternation of sexual with asexual reproduction. [1855 60] * * * In biology, alternation of a sexual phase (gametophyte) and a nonsexual phase… … Universalium
plant development — Introduction a multiphasic process in which two distinct forms succeed each other in alternating generations. One form, created by the union of sexual cells (gametes (gamete)), contains two sets of similar chromosomes (diploid). At sexual… … Universalium
alternationof generations — alternation of generations n. The regular alternation of forms or of mode of reproduction in the life cycle of an organism, such as the alternation between diploid and haploid phases, or between sexual and asexual reproductive cycles. Also called … Universalium
plant — plantable, adj. plantless, adj. plantlike, adj. /plant, plahnt/, n. 1. any member of the kingdom Plantae, comprising multicellular organisms that typically produce their own food from inorganic matter by the process of photosynthesis and that… … Universalium
Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… … Universalium
climate change — Introduction periodic modification of Earth s climate brought about as a result of changes in the atmosphere as well as interactions between the atmosphere and various other geologic, chemical, biological, and geographic factors within the Earth … Universalium
Empedocles — M.R.Wright INTRODUCTION Empedocles was a native of Acragas (Agrigento) in Sicily, a Doric colony founded on the south coast of the island in the sixth century BC, which soon grew to rival Syracuse in its prosperity. A line of temples, many of… … History of philosophy
Meiosis — Not to be confused with miosis, mitosis, or myositis. For the figure of speech, see meiosis (figure of speech). Events involving meiosis, showing chromosomal crossover Meiosis (pronounced /maɪˈoʊsɨs/ … Wikipedia
Red algae — Taxobox color = #taxobox color|Plantae name = Red algae image width = 240px domain = Eukaryota unranked phylum = Archaeplastida phylum = Rhodophyta phylum authority = Wettstein, 1922 subdivision ranks = Class subdivision = *Rhodophyceae(There… … Wikipedia