Kew’s Herbarium is home to one of the largest collections
Of dried plant specimens in the world
Over the past two centuries
taxonomists have organized
and catalogued over 7 million specimens
The original purpose in collecting all these together
Was figuring out what they could be used for
And if you could cultivate them
Where were the best places to cultivate them outside their native range
So you had tea from China
bananas from Malaysia
coffee from Africa
and oil producing trees from Brazil
you could say that it was a collection sorts
in the 18th century
Swedish botanist Carl Linnaeus
Developed the binomial system of naming
So each species had a two-part of name
a Larger category which we now called genus
And one referred to the species
That was really a breakthrough
Because that allowed people very quickly and accurately
To tell each other which species they were talking about
In the 19th century
Charles Darwin published his revolutionary book
On the Origin of Species
He had observed that different plants had similarities to each other
And he realized that all of them must share a common ancestor
The idea of classification became stronger
And Kew in fact developed its own system of morphological classification
Entirely based on what you could see with a naked eye
And a little bit that you could see with a microscope
The plant tree began to take form
Chapter four 1980s
our most recent development in understanding the family tree
came with the introduction of DNA technology in the 1980s
By being able to look at the molecule of plants
we can now understand the evolution of plants over time
and trace in incredible detail
the diversity back to its simplest origins
What’s incredible is that 90 percent of the family that has been
previously defined based on morphological characters were verified by the DNA work
500 million years ago,
it was just various groups of algae
red
green
brown
the green algae
started to first make their way onto the land
developing into more complex structures
like the liverworts
hornworts
or mosses
100 million years later we started to see things such as
club mosses
ferns
and horsetails
and then 50 million years later
plants with seeds were organized into cones came into existence
such as conifer cycads
and spruces
the world was a green place
lots and lots of green
a few brown cones
but color wasn't there
everything was just very photosynthetic
very nice
roughly about 140 million years ago
the flowering plants appeared
and really that’s still a bit of a mystery
350 thousand species in total
incredibly complex and diverse
the lilies
orchids
grasses
palms
gingers
magnolias
cacti
peas
and beans
potatoes
roses
mints
flowers really change the world
they made possible an incredible diversity
of other kinds of lifestyles for other organisms
they feed us, clothe us
provide us with medicines
products to build our homes out of it etc.
the plant family tree gives us a frame work for asking
the really important question about how our eco system funtion
It’s those connections that tell us
most of what we want to know about evolution of life
of not just plant but the other things that depend upon plants
which is everything
the evolutionary tree is a great achievement
you can see it as a tool for the rest of science
the rest of humanity
the process now is 95% complete
so the story is pretty well told now I would say