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Angiosperms -- that is, flowering plants -- only evolved relatively recently on an evolutionary timescale, about 125 millions years ago. So for most of the history of life on earth there have been no flowering plants. Thus it seems highly likely that if angiosperms were to suddenly disappear, life on earth would continue. There might be a massive disruption ...


7

The stinging hairs (trichomes) of the common North American nettle (Urtica dioica) are sharp, pointed cells. These nucleated cells are embedded in a base of smaller epidermal cells. The shaft of the trichome is composed of silica. Upon touch, the tip breaks off, leaving a sharp tip similar to a hypodermic needle. The hollow trichome penetrates the skin, and ...


5

(This isn't an answer, but hopefully it will help get it past the experimental design into just solving the equation.) Where did you get that α0 was not determined from their data? On p. 10 (256), they state, "The prevailing direction of effective pollen dispersal within neighbourhoods (a0) that gave the best fit of the model was 91 degrees from north ...


2

It depends on the plant. All angiosperms (as far as I know) will produce flowers even in the absence of pollinators, the question is whether or not the plant will bear fruit. Some species are wind-pollinated and do not require insects for pollination at all. They will bear fruit just fine without insect intervention Other species are self-compatible and ...


2

It is a Hoya Carnosa Krinkle Kurl flower. It is native to Australia and East Asia. Hoya Carnosa links to wikipedia and Krinkle Kurl links to plant rescue in case you want to read more on it.


2

Germination of the pollen tube begins when the pollen grain becomes hydrated on the tip of the stigma. The pollen grain absorbs water and also exchanges signals with the stigma. Microchannels form between the pollen grain and the tip of the stigma papillae and water is transferred from the stigma to the pollen grain (Taylor 1997). cAMP, which is produced by ...


2

No, it would not be accurate to label them clones, and the organism still goes through sexual reproduction even if they are selfed. Selfed offspring would get two copies of the "same" chromosome (when selfed within the same prothallus), when the parent might have two chromosomes of different origins, and there will also be recombination during meiosis ...


1

In ferns (and seed plants) the dominant, largest stage of life is the diploid sporophyte. Within the sporophyte, meiosis occurs producing haploid spores. These spores are dispersed and grow into the small haploid gametophyte, AKA the prothallium. The gametophyte produces haploid gametes - both egg and sperm coming from the same individual, usually. The sperm ...


1

You can try http://timetree.org/ to get the divergence time if you already have the names of the taxa.


1

Maybe you could get some information from the Angiosperm Phylogeny Group: http://www.mobot.org/MOBOT/research/APweb/ They even have a tree where model organisms are highlighted: http://www.mobot.org/MOBOT/research/APweb/trees/modeltreemap.html


1

If you know the species name, you can search TreeBase to find previously published phylogenetic trees which will point you towards close relatives to your species. Depending on how obscure your taxon is, though, you might not find much.



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