The New Year is nearly upon us. This time of year we think
of birth, potential, new chances to accomplish goals. The fresh start is
symbolized by the New Year’s baby entering as the old man of the past year
exits stage right.
 |
|
Say
hello to the dancing baby, perhaps the world’s original viral
video
and internet meme. If you remember when the baby first
showed
up, you have seen at least 18 New Years and probably
watched
Ally McBeal.
|
Unfortunately, it’s not so easy. Do you volunteer to track
every naked mole rat to see which one lives the longest? How will we account
for the hundreds of thousands, or even millions, of species we haven’t discovered as of
yet? Maybe we will just have to use examples for those individuals and species
we happen to have data for – that, and maybe some speculation.
A researcher in 1999 proposed a hypothesis that
species body mass directly relates to longevity, ie. the bigger the animal, the
longer it lives. There are myriad examples that don’t seem to follow his rule,
and his hypothesis has met with substantial resistance, but the paper has been
cited more than 1500 times so somebody’s buying it. More recent evidence from
his group suggests that metabolic rate may be as telling as overall body size.
It’s a live fast, die young hypothesis.
 |
|
One
of these images is of Misao Okawa, the oldest living human
as
of late 2014. The other image is of Miley Cyrus and some of
her
backup dancers. I don’t see Misao, so she must still be
working
on her moves (Miley is the one in the middle).
|
Humans are amateurs when it comes to longevity. Jonathan, a Seychelles
giant tortoise (Disochelys hololissa)
is said to have seen 182 New Years. This is an estimate; a picture of Jonathan
in 1882 shows him to be adult sized, and this takes about 50 years. So they
guess he was born about 1832.
Bowhead whales (Balaena
mysticetus) are second in size only to Blue whales, and individuals of this
species are known to live for 210 years or more, making it the oldest living
mammal species. Believe it or not, we can tell this by examining their ears
after they die. They build a specific number of layers of ear wax each year, so
we can just count the rings, exactly like with a tree – only yuckier.
A new study shows that bowhead whales have altered gene
expression that may account for their longevity, especially in terms of fat
metabolism and insulin signaling. The same study also shows that bowheads have
parallel changes in gene expression that are seen in other species that live
longer than one would expect – like the naked mole rat and Brandt’s bat.
 |
|
The
quahog clam isn’t really that big, so it defies the hypothesis
about
size and longevity. The bottom image is a micrograph of
a
quahog shell. You can count the layers to determine how
many
growing seasons it has lived through, not necessarily
how
many years. A new study examined the layers to estimate
ocean
conditions over the last 400 years.
|
The oldest living individual organism THAT WE KNOW OF is a
bristlecone pine tree in the White mountains of California. It's known to have
seen at least 5064 Rose Bowl Parades. People can visit its grove to wish it a
happy birthday, but you’ll have to guess which tree is the oldest – only one
man knows and he isn’t telling.
In truth, the idea of what is old is not so
easy to discern. As humans, we have a prejudiced notion of what “old” means. We
are born, we live, we die. The person who remains vertical for the most days
wins. But many organisms just don’t play by our rules. As a result, they can “live”
for hundreds of thousands of years.
 |
|
This
isn’t the oldest Bristlecone Pine – or maybe it is. The Forest
Service
won’t tell anyone which of the pines in this California
locale
is actually the oldest. The unnamed tree is 5064 years
old,
and shares its forest with another pine named Methuselah,
who
clocks in at 4847 years old.
|
Samples of bacteria were “life suspended” until brought out
in a Siberian ice core. Once thawed they began to divide. Are those bacteria
several minutes old or 500,000 years old? They wouldn’t be growing and dividing
except for the ice coring process. Maybe global warming will bring billions of
old species back to life.
Let’s look at another way to circumvent the traditional idea
of long life. Quaking Aspen trees (Populus
tremuloides) live as colonies of clones. In the Pando clone of Utah, great
stands of these trees cover more than 100 acres and constitute the heaviest
single organism on Earth – over 6000 tons.
They all stem from one progenitor tree and they are all connected
by one root system; roots sent out in a direction will turn upward and give
rise to new trunks. Do we count the newest trunk to sprout and the first trunk
that may have fallen over 80,000 to 1 million years ago as the same organism
and the same life?
 |
|
When
injured, starved or bored, the immortal jellyfish will revert
from
adult form to juvenile form and just grow up again. Can you
imagine
an infinite number of adolescent periods? Imagine
the
parents!
|
In typical jellyfish species, juvenile jellyfish live as
polyps, then become bell-shaped medusae as adults – then die. However, the
immortal jellyfish can revert from medusa to polyp and then grow up again. It can
theoretically do this indefinitely, making the jellyfish ostensibly able to
live forever. In practice, most die from disease or predation, but the
possibility of infinite life is there.
One moral of our story – don’t worry about how many New
Years Days you may or may not get to see – your number isn’t going to mean
anything to anyone else. While studying old things may extend our lives in the
future, be sure that you make of the most of the New Year you are being given
now.
Contributed by Mark E. Lasbury, MS, MSEd, PhD
No comments:
Post a Comment