The Accountant Nov-Dec 2016

ENVIRONMENT
ways birds (and other animals, plants, and
landscapes) support and improve human
life is “ecosystem services.” understanding
these services, and quantifying their dollar
value, has been a growing priority for
scientists worried about the unprecedented
loss of biodiversity we’re now seeing—by
one popular estimate, some 27,000 plant
and animal species each year, many of
them driven extinct by human activity.
What is the origin of birds?
The origin of birds refers to the initial
stages in the evolution of birds. The
scientific consensus is that birds are a
group of theropod dinosaurs that evolved
during the Mesozoic Era.
A close relationship between birds and
dinosaurs was first proposed in the
nineteenth century after the discovery
of the primitive bird Archaepteryxin
Germany. Birds share many unique
skeletal features with dinosaurs. Moreover,
fossils of more than twenty species
of dinosaur have been collected with
preserved feathers. There are even very
small dinosaurs, such as Microraptor
and Anchiornis, which have long, vaned,
arm and leg feathers forming wings. The
Jurassic basal avialan Pedopenna also
shows these long foot feathers. Witmer
in 2009 concluded that this evidence
is sufficient to demonstrate that avian
evolution went through a four-winged
stage.
Fossil evidence also demonstrates that
birds and dinosaurs shared features such
as hollow, pneumatized bones, gastroliths
in the digestive system, nest-building and
brooding behaviors. The ground-breaking
discovery of fossilized Tyrannosaurus soft
tissue allowed a molecular comparison of
cellular anatomy and protein sequencing
of collagen tissue, both of which
demonstrated that T. rex and birds are
more closely related to each other than
either is to Alligator. A second molecular
study robustly supported the relationship
of birds to dinosaurs, though it did not
place birds within Theropoda, as expected.
This study utilized eight additional
collagen sequences extracted from a femur
of Brachylophosaurus Canadensis, a
hadrosaur. A study comparing embryonic,
juvenile and adult archosaur skulls
concluded that bird skulls are derived from
those of theropod dinosaurs by progenesis,
a type of paedomorphic heterochrony,
which resulted in retention of juvenile
characteristics of their ancestors.
The origin of birds has historically
been a contentious topic within
evolutionary biology. However, only a
few scientists still debate the dinosaurian
origin of birds, suggesting descent from
other types of archosaurian reptiles.
Among the consensus that supports
dinosaurian ancestry, the exact sequence
of evolutionary events that gave rise to the
early birds within maniraptoran theropods
is hotly disputed. The origin of bird flight
is a separate but related question for which
there are also several proposed answers
(wiki)
Bird watching
Bird watching is a pass time that many
people in developed countries have
indulged in for years; today more and more
people in Africa have taken it up I know
people who will always ensure there is
food in their backyards for birds. But what
exactly excites people about this favorite
pass time? For me, it is their beautiful
singing, their blend of colours, and their
flight, feeding their young and flocking
together, how about you? Following are a
few reasons about.com gives to explain the
pleasures of bird watching….
Seeing birds by feeding
The most obvious benefit of feeding birds
is simply the enjoyment their company
can bring us. While birds will naturally
visit any backyard, adding feeders and
different food stations will attract more
species, from hummingbirds and tanagers
to sparrows, chickadees, woodpeckers and
other unique species, and many backyard
birders keep “yard lists” to track the
different species they see right at their
doorsteps. The colors, songs and behaviors
that birds bring with them can all be
enjoyed by dedicated backyard birders,
but there is much more to appreciate by
feeding birds.
More Benefits of Feeding
Birds
Depending on the number of feeders
you have, the types of foods you offer
and the birds that take advantage of your
generosity, there are many benefits of bird
feeding you can enjoy.
Education: Feeding birds can be a
fascinating educational activity for all ages.
By changing feeder styles and food types
you can learn more about the birds that
visit, and just observing the birds will help
you learn about behaviors, identifications,
personalities and other aspects of your
local avifauna and how birds change
season by season.
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