Good morning my name is Mark Patterson and I'm the curator of the Cruickshank
Botanic Garden indeed we're in part of the Botanic Garden today with a range of
sounds around us. You'll hear the birds in a moment you'll also hear a lot of
younger voices so this is a Botanic Garden that is primarily for research,
teaching but also public engagement and that involves school groups of all ages
learning about the flora and indeed the seasons that are so obvious within a
Botanic Garden and particularly in this context the most northern University
Botanic Garden here in Aberdeen. I'm also here, and I'll introduce my colleague Dr.
Tyler Stevenson in a moment with one of our leading scientists who specializes
in looking at the biological rhythms that are paramount for life on Earth. In
my context of course as somebody who's a trained gardener and is managing a
botanic garden collection we're here on the 20th the December, a day before
winter solstice, a day before we have our shortest day our longest evening two
days away from the days beginning to get longer once again and flora is an
indicative type of of biology on this planet showing how light levels are such
a important factor for growth. Looking around the Botanic Garden today we
do have a few snowdrops already showing first bloom but we know generally
speaking the growing season won't be for another 12 weeks. So as we make our way
through just a smidge of the garden here I'll be able to introduce you to
Tyler Stevenson and he will be able to explain his work with much more care and
attention than I can but suffice to say that his work is looking at, and Tyler
your work is looking at, how different environmental factors promote, change,
alter how life evolves in its lifecycle but particularly breeding cycle exactly
and when we look in the environment for a number of different cues that we could
use to time our physiology and behavior and when we look across organisms from
plants to animals to humans the most reliable consistent predictive
environmental cue is the annual change in day length. So right now we're gonna be
having the winter solstice up in Aberdeen we're gonna have about 6 hours
and 30 minutes of daylight and this is rapidly going to change as we enter the
spring period. In plants, animals and humans we use this rapid change in day
length to coordinate a number of different physiological behavioral and
cognitive processes and this is important because you wouldn't want to
use any environmental cue such as temperature or rainfall because these
are cues that are going to be highly variable day to day. I know precisely
when the sun's gonna rise tomorrow. I know precisely when the Sun is going
to set tomorrow and I know that we're going to add two to four minutes every
single day. You don't have that same type of reliability when it comes to
precipitation or temperature so it's the annual change in day length that I find
is one of the most important environmental cues that we need to study.
I would also perhaps suggest that as a serious positive knowing that biology has
broadly across the planet evolved to match day length or indeed levels of
darkness it is the one great factor that will not change with climate change
occurring and knowing that that may have other negative impacts on how life evovles
and continues to develop across this planet.
Exactly. So one of the biggest challenges for plants and animal species is to coordinate this
mismatch that we have right now. We have a reliable day length cue but an
unreliable temperature cue. So animals that are going to rely for I'm primarily
on the temperature queue are going to have a phenomenal mismatch and it's that
day length queue that is going to be that anchor that all species are going
to need to integrate or to detect in order to accommodate the changes that are
gonna come with climate change. We see that in the garden here. I've mentioned
we already have some snowdrops in flower. We might associate that
time of the year but generally after Christmas not before and I think it's
less likely to do light levels on this occasion it's because we are
getting warmer soil temperatures and lasting longer.
So is that a variant within?
Exactly. So they need to be able to integrate all environmental cues but
it's day length that is the primary predictive cue and all other cues are supplementary cues.
Fascinating. Thank you.