AskDefine | Define excavate

Dictionary Definition

excavate

Verb

1 lay bare through digging; "Schliemann excavated Troy" [syn: unearth]
2 find by digging in the ground; "I dug up an old box in the garden" [syn: dig up, turn up]
3 form by hollowing; "Carnegie had a lake excavated for Princeton University's rowing team"; "excavate a cavity"
4 remove the inner part or the core of; "the mining company wants to excavate the hillsite" [syn: dig, hollow]

User Contributed Dictionary

English

Verb

  1. To make a hole in (something); to hollow.
  2. To remove part of (something) by scooping or digging it out.
  3. To uncover (something) by removing its covering.

Related terms

Translations

to make a hole in (something); to hollow
  • Hungarian: kiás, kiváj
to remove part of (something) by scooping or digging it out
  • Hungarian: elhord, kiemel, kikotor, kimélyít, alámos
to uncover (something) by removing its covering
  • Hungarian: felás, feltár

Extensive Definition

The excavates are a major assemblage of protists, often known as Excavata. The phylogenetic category Excavata contains a variety of free-living and symbiotic forms, and includes some important parasites of humans. Many excavates lack 'classical' mitochondria - these organisms are often referred to as 'amitochondriate', although, most, perhaps all, retain a mitochondrial organelle in greatly modified form. Others have mitochondria with tubular, discoidal, or in some cases, flat cristae. Most excavates have two, four, or more flagella and many have a conspicuous ventral feeding groove with a characteristic ultrastructure, supported by microtubules. However, various groups that lack these traits may be considered excavates based on genetic evidence (primarily phylogenetic trees of molecular sequences). Most excavates fall into one of four groups, which may be treated as phyla: Of these, the Percolozoa (Heterolobosea) and Euglenozoa appear to be particularly close relatives, and are united by the presence of discoid cristae within the mitochondria. Most jakobids have tubular cristae, like most other protists, while the metamonads are unusual in having lost classical mitochondria - instead they have 'hydrogenosomes', 'mitosomes' or uncharacterised organelles. Excavate relationships are still uncertain; it is possible that they are not a monophyletic group.
Certain excavates are often considered among the most primitive eukaryotes, based partly on their placement in many evolutionary trees. This could encourage proposals that excavates are a paraphyletic grade that includes the ancestors of other living eukaryotes. However, the placement of certain excavates as 'early branches' may be an analysis artifact caused by long branch attraction, as has been seen with some other groups, for example, microsporidia.
The monophyly of the excavates is far from clear, although it seems like there are several clades within the excavates which are monophyletic.

References

excavate in Catalan: Excavat
excavate in German: Excavata
excavate in Spanish: Excavata
excavate in Irish: Excavata
excavate in Japanese: エクスカバータ
excavate in Polish: Excavata
excavate in Serbian: Excavata

Synonyms, Antonyms and Related Words

avulse, bore, bring to light, bring up, burrow, clear, countersink, cut out, deepen, delve, depress, deracinate, dig, dig out, dig up, dike, disclose, disentangle, disinter, dive, draw, draw out, dredge, dredge up, drill, drive, eradicate, evolve, evulse, excise, exhume, expose, exsect, extract, extricate, ferret out, fish up, furrow, get out, gouge, gouge out, groove, grub, grub up, hollow out, lay bare, lower, mine, pick out, pluck out, pluck up, pull, pull out, pull up, quarry, rake out, remove, reveal, rip out, root out, root up, sap, scoop, scoop out, scrabble, scrape, scratch, shovel, sink, spade, take out, tear out, trench, trough, tunnel, turn up, uncover, unearth, unravel, uproot, weed out, withdraw, worm out, wrest out
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