seed

Tumor

...umors do not invade neighboring tissues and do not seed metastases, but may locally grow to great size. They usually do not return after surgical removal. Depending on tissue of origin, tumors may be: Tumors of epithelial origin. squamous epithelium: squamous cell papilloma , squamous cell carci...

Species

...irely absent. This might be a distinctively shaped seed pod, an extra primary feather, a particular courting behaviour, or a clearly different DNA sequence. Sometimes it is not possible to isolate a single difference between species, and several factors must be taken in combination. This is often the c...

Plant

...s Ophioglossophyta - adderstongue ferns seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gn...

Plant

...s Ophioglossophyta - adderstongue ferns seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gn...

Phloem

...sources, and storage organs are sinks. Developing seed -bearing organs (such as fruit ) are always sinks. Because of this multi-directional flow, coupled with the fact that sap cannot with ease move between adjacent sieve tubes, it is not unusual for sap in adjacent sieve tubes to be flowing in opposite...

Parthenogenesis

...eans the growth and development of an embryo or seed without fertilization by a male . Parthenogenesis occurs naturally in some lower plants (called agamospermy ), invertebrates (e.g. water fleas , aphids ) and some vertebrates (e.g. lizards , salamanders , some fish , and even turkey...

Embryo

...ts : In botany , a plant embryo is part of a seed , consisting of precursor tissues for the leaves, ...yo begins to germinate — grow out from the seed — it is called a seedling . Animals : The embryo of vertebrates is defined as the stage...

Artificial life

...ication in the 1950s with a model train set -- a seed "organism" consisting of a "head" and "tail" boxcar could use the simple rules of the system to consistently create new "organisms" identical to itself, so long as there was a random pool of new boxcars to draw from. Edward F. Moore proposed "Artifi...