Ethology, which looks at animal
behavior and its evolutionary basis
and development, is a major
component in the modern study
of organisms. Back in 1837, British
entomologist George Newport
discovered that moths and bees
could raise the temperature of their
thorax by quivering their muscles.
From the 1970s onward, German-
American entomologist Bernd
Heinrich and others uncovered
more thermoregulatory adaptations
that have helped insects thrive.
As heterotherms, they are able
to maintain different temperatures
in different parts of the body.
Modern research now combines
laboratory experiments, field
observation, and new technology
such as infrared thermography
to understand insect behavior
in ever more detail.Field observations are a key tool in
ethological research. In the 1940s,
British ornithologist David Lack
investigated the factors controlling
the number of eggs birds laid
(clutch size). His food limitation
hypothesis states that the number
of eggs laid by a species has
evolved to match the food available.
Evolutionary pressure has created
a correlation between clutch size
and food availability.
Austrian zoologist Konrad
Lorenz and Dutch biologist Nikolaas
Tinbergen also studied animals in
the wild to help understand their
behavior. Lorenz’s 1949 work Man
Meets Dog explains the loyalty
of a pet dog to its owner in terms
of canines’ instinctive loyalty
to their pack leader in the wild.
Tinbergen’s field experiments
showed how gull chicks, which tapa red spot on a parent’s beak when
they want food, will tap colored
marks painted on a model beak.Human traits
As well as these short-term studies,
British primatologist and ethologist
Jane Goodall conducted field
observations over a longer period,
studying chimpanzees in Tanzania
from 1960 to 1975. Her findings
challenged the view that human
behavior is totally unique in the
animal world, and indicated that
chimps are behaviorally closer
to people than had generally been
assumed. She noted, for example,
that chimps display a whole range
of facial expressions and other body
language to indicate their mood, are
toolmakers and users, often behave
cooperatively, and sometimes go
into battle against rival groups. ■THE VARIETY OF LIFE
2005
The first gene mapping
confirms that humans
share 97–99 percent of
their DNA with the other
great apes.101
Jane Goodall sets up
a camp in Tanzania to
research chimpanzees in
the wild, discovering many
traits shared by humans.1960
1981
Insect Thermoregulation
by Bernd Heinrich
explains how insects
are able to control their
own temperature.1947
David Lack publishes
an article on variations
in bird clutch size as
an evolutionary
adaptation.In Man Meets
Dog, Konrad Lorenz
describes the instinctive
behavior of animals and
its evolutionary origins.1949 2007
In the US, the Human
Microbiome Project is
launched, to map all the
microbes associated with
a healthy human body.US_100-101_Ch_4_The_variety_of_life_Intro.indd 101 12/11/18 6:24 PM