No.
These examples have all been changes within a species.
You may be wondering how species give rise to different species.
This puzzle is much harder to understand because, unlike the examples
above, we cannot observe species evolving from one to another.
The time scales are usually far too long.
Usually.
There are various ways to define a "species" (and we will come to that in a later lesson). One way to define a species is as a group of plants or animals that are reproductively isolated from another group. That means a species cannot breed outside its own species. If we accept that as a definition then we can "create" a new species and it is particularly easy to do with plants.
Lets consider polyploidy in plants.
Polyploidy means "lots of chromosomes" and colchicine
is a chemical that interferes with the number of chromosomes passed
to the next generation. So, colchicine can cause polyploidy.
The primrose is a common garden plant in the Genus Primula.
There are many species of primrose but two are relevant to this
story - Primula verticillata and Primula florbunda.
Both have 18 chromosomes each and by crossing them you can produce
a hybrid plant that also has 18 chromosomes. These hybrid Primula
are infertile. (Most hybrids are infertility. The mule, a cross
between a horse and an ass, is a good example of an infertile hybrid.) Plants, unlike
animals, can often be "forced" through this infertility
by adding colchicine. The colchicine allows unusual numbers of
chromosomes to be passed along as gametes. When colchicine was
used on the Primula hybrids they produced "healthy"
gametes and were able to be crossed amongst themselves to produce
a new polyploid Primula with 36 chromosomes. This new species
is called Primula kewensis and it cannot breed with either
of its parent species (Primula verticillata or Primula
florbunda) but it is very capable of producing healthy offspring
from its own kind.
This fits our definition of a new species.
This "trick", of using colchicine to move a hybrid through
its infertility and create a new species with a different number
of chromosomes, is now a common agriculture and horticulture technique
for creating new artificial species.
But does polyploidy happen in nature?
Yes, it does.
Colchicine helps the experimenter and moves evolution along quickly
but there are natural agents in the environment that will produce
polyploids and fertile hybrids. (As a matter of fact, colchicine
is extracted from some species of plants!)
Many families of wild flowers are composed of species that consist
of simple multiples of a basic number of chromosomes.
By looking at the number of chromosomes in groups of related species,
it is possible to guess which originated from polyploid hybridisation.
We can then recreate the event in the laboratory.
For example, the mint Galeopis tetrahit has a set of chromosomes that appear to be the addition of the chromosomes from two other mints Galeopis pubescens and Galeopis speciosa. When these two species were crossed the "new" species created is able to breed successfully with the wild Galeopis tetrhit.
It is estimated that 70-80% of angiosperms (plants with hard seeds) are the product of natural polyploid evolution.
Polyploidy is common amongst plants but usually not involved in
the speciation of animals. However, there is plenty of evidence
of speciation amongst animals and one particularly common and
easy to study group of animals lend themselves very well to studies
in evolution because they have so many species.
Take a guess as to which of these groups of animals have the
most species.