Evolution of species
– where do species come from?
Think about the term
species, there is nothing called a specie, species is singular or plural, species
has come about b/c of ppl like Linnaeus who want to try and organize the
Older son’s bedroom – messy and dirty, this organization has led us to
in biological sciences to place animals and plants in similar groups, taxonomic
groups, there is still variation among groups.
It doesn’t take scientists to
perceive scientists among different things; primitive groups can do this as
was an evolutionary biologist who studied birds at Harvard
and in 1927, he led scientists to New Guinea, went to
talked to tribes to find different names of birds, came up with about 137
names for different birds.
So they then went out to collect birds and found out
that they came up with 138 names, so these untrained primitive ppl had only
confused 1 species or scientists did so, so this is indicative that all of us can
see the differences in living forms.
The term species has gone thru its own
kind of evolutionary process when we think back to time of Aristotle,
was then and it was held in common by ppl, but we have
already learned not the believe this, it is a static unified immutable form that is
defined by a place and lives in real/ideal/eternal world.
So, needless to say
this went away.
Now we look at
– the morpho
species, this is where we thank Linnaeus, this concept was used by L to put
together his thing in the 1750s, looking at physical shape or w/e and grouping
it, this process is ok except for situations where we have a lot of
When the variation among species is greater than variation
between species, we have a problem.
Most scientists use this today more than
any other kind.
The third one is proposed by Mayr in 1942.
– things are changing, ppl are challenging issues, it isn’t as well
accepted today as it was b/c there are clear deviations, but it is a genetically
distinct group of natural populations that share a common gene pool and are
reproductively isolated from other such similar groups.
They key here is
was defined where he said that the biological
species is reproductively isolated, etc.
This is important because there could
be some species that are similar in terms of color so it may be hard to separate
them, the physiology or ecology or behavior could be similar, but they are
reproductively isolated, a cessation or termination of gene flow helps
determine different species.
this means that a species is
reproductive compatible, even if they are located geographically apart from
refers to situations or encounters that occur within
You may have a bird feeder at home, and a white throated sparrow
is on it and another one comes, the original one bites at the other one.