Charles Darwin wrote about it 150 years ago: animals don’t pick their
mates by pure chance – it’s a process that is deliberate and involves
numerous factors. After decades of examining his work, experts agree
that he pretty much scored a scientific bullseye, but a very big
question is, "What have we learned since then?" asks a Texas A&M
University biologist who has studied Darwin’s theories.
Adam Jones, an evolutional biologist who has studied Darwin’s work
for years, says that Darwin’s beliefs about the choice of mates and
sexual selection being beyond mere chance have been proven correct, as
stated in Darwin’s landmark book The Descent of Man, and Selection in
Relation to Sex.
Bottom line: It’s no accident that certain peahens submit to
gloriously-colored male peacocks, that lions get the females of their
choice or that humans spend hours primping to catch the perfect spouses –
it’s a condition that is ingrained into all creatures and a conscious
"choice" is made between the two so the romantic fireworks can begin.
Jones says Darwin set the standard for original thinking about animal
reproduction and was first scientist to propose plausible mechanisms of
evolution, and from there he took it one step further – he confirmed
that animals’ mating choices can drive evolutionary change.
"He noticed that birds, especially, seemed to be a bit picky about
who they mated with," Jones explains. "He discovered that birds –
especially females – had preferences and that they did not just choose a
mate randomly. He believed this is due to beauty of the plumage, that
females usually selected the most colorful males.
"That was an important first step, and it’s given us models to work
from to try to answer other big questions."
Those include determining methods to find out the actual criteria
used in choosing a mate, what methods work and which do not, and the
passing of genes on to the next generation, a field of study Jones says
gained popularity in the 1970s and 1980s.
"Another big recent advance was the development of molecular markers,
which allow us to perform paternity testing," Jones adds.
"These markers can be applied to animal populations, and they give us
a definitive record of who is mating with whom and what offspring
resulted from the mating events. And also, what is the driving force
behind sexual selection? We have an unprecedented ability to document
mating patterns but we still don’t completely understand why some
populations experience strong sexual selection and others don’t."
Jones notes that other key questions Darwin’s work uncovered but has
not yet answered include the role of population characteristics and the
environment and how they work together to produce strong sexual
selection, and also what determines whether or not female choice will
evolve in a particular species.
And perhaps the biggest question of all: How does all of this pertain
"Darwin concluded that sexual selection existed in the animal world
and that humans definitely followed a similar process," Jones confirms.
"But he realized he had to explain it first as it related to animals.
Darwin thought that sexual selection was an important process in
humans, both for males and females. But how much has sexual selection
acted on males versus females in humans? Today, while we are celebrating
the 200th year of the birth of Charles Darwin, we know sexual selection
occurs and is very important but there are still many unanswered
questions about precisely why and how it works, especially in humans."
Source : Texas