Fossils of isolated land plant spores (Heckman et al, 2001) suggest land plants may have been around as long as 475 million years ago; Fossils of land plant spores within plant fragments (Wellman et al., 2003) date back to 425 million years ago ( these were found in Oman and appear to be liverwort-like, although elaters are noticeably absent!)
The noun PUPILLARY REFLEX has 1 sense: 1. reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller. Familiarity information: PUPILLARY REFLEX used as a noun is very rare. Dictionary entry details.
Your pupils tend to dilate, or widen, when eyeing somebody that you find particularly attractive.â¦ Read more Read more. Pupil dilation, what's also referred to as mydriasis, happens when one of two muscle groups become activated, namely the iris sphincter (yes, that's what it's called) and the iris dilator.