Download Cultural Anthropology Chapter 2 Professor Solis

AP Biology
CHAPTER 1& 2
PROFESSOR SOLIS
The Scientific Method



Relies on empirical
knowledge (experiment or
observation)
Develop an hypothesis
(provisional explanation)
Identify a research question
and then gather
information to answer it.
The Development of Evolutionary Theory


Throughout the Middle Ages the
European worldview was that
all aspects of nature (and their
relationship to one another)
never changed.
 Life forms couldn’t and
didn’t change
This is known as the belief in
the “Fixity of the Species”
The Scientific Revolution


What transformed centuries old belief in a static world, to
belief in one that is in continuous motion?
Age of exploration allowed for the growing interest in human diversity

Other traditional beliefs were being called into question…
 Copernicus and Galileo challenge Aristotle’s
geo centric view of the world by the helio
centric view – challenges the Catholic Church
(dominant ruling body during the Middle
Ages and the Renaissance)
Age of the Naturalists

John Ray (16th century - British).
Began with the classification of
plants. Discovered that certain
species of plants share
characteristics of other species of
plants. Groups of plants and
animals could be differentiated
from other groups by their ability
to mate with one another. Coined
the term “species”.
 Reproductively Isolated:
Pertaining to groups of
organisms that, mainly
because of genetic
differences, are prevented
from mating and producing
offspring with members of
other groups.
Age of the Naturalists
contd.

Carolus Linnaeus(18th century – Sweden).
Best known for developing a classification of
plants and animals, Systema Naturae
(Systems of Nature) first published in 1735.
Built upon Ray’s system of classification, but
added humans to the classification of
animals. By doing so, he recognized humans
as being part of the natural world, and
thereby subject to the same laws of nature.
This was a profound breakthrough during
this time. (believed in fixity of species)
 Established, “binomial nomenclature” –
convention of using genus and species
names to refer to a species (Homo
sapiens)
 Established, “taxonomy”: The branch of
science concerned with the rules of
classifying organisms on the basis of
evolutionary relationships.
Age of the Naturalists
contd.

Comte de Buffon (Georges Louis
Leclerc 18th century - French).
Buffon did not believe in the
perfection of nature, nor even
that nature had a purpose, but
he did recognize the
relationship between the
external environment and living
forms. Wrote Natural History
published in 1749. (culture can
be influenced by environmental
conditions)
Age of the Naturalists
contd.


Erasmus Darwin (18th century –
British). Laid the foundation for
his grandson Charles Darwin’s
work on natural selection.
Erasmus expressed these ideas
and commented on human
evolution.
Jean Baptiste-Lamarck (18th
century – French). Believed that
species change was influence by
environmental changes. He is
best known for the theory of the
inheritance of acquired
characteristics. But he didn’t
get it quite right!
Age of the Naturalists
contd.

Georges Cuvier (18th century –
French). Vertebrate
paleontologist. Adamantly
insisted on the fixation of the
species. Cuvier explained the
fossil record as the result of a
succession of catastrophes
followed by new creation
events. (proposed the concept
of catastrophism)
Age of the Naturalists
contd.


Charles Lyell (18th & 19th century – British). Considered the
founder of modern geology.
Observed that the geologic processes that are observed in
the present: earthquakes, volcanic eruptions, floods, water
erosion, etc.; are the same as those that have occurred in the
past. These processes create the geologic landscape we see
today. Principles of Geology 1830-1833.
 Uniformitarianism: The theory that the earth’s features are
the result of long term processes that continue to operate
in the present as they did in the past. Opposed
catastrophism and contributed strongly to the concept of
immense global geologic time.
 i.e. aspects of the earth are variable, but the processes
are constant
 Proposed the earth to be far older than anyone had
previously suspected. (4.54 billion years)
Age of the Naturalists
contd.

Thomas Malthus (18th century
– British). 1798 – Essay on the
Principle of Population.
Malthus pointed out that if not
kept in check by limited food
supplies, human populations
could double in size every 25
years. That is, population size
increases exponentially, while
food supplies remain relatively
stable.
Age of the Naturalists
contd.

Charles Darwin (19th century – British) Principle of
natural selection. Did not suggest human evolution.
Restricted his theory to plants and animals. “Survival
of the Fittest” – those with characteristics best suited
to their environment have the best chance of
surviving, producing offspring and populating that
geographical region. Those less suited, will not be
able to procure resources and will die out.
 Set sail on HMS Beagle December 17, 1831.
 Travels to South America, observes giant tortoises,
finches, and fossils of large extinct mammals
 Evolution was originally termed, “transmutation”
– the change of one species to another. (original
proponents were anti-Christian – no doubt giving
rise to opposition persistent today)
Darwin contd.



Set sail on HMS Beagle December 17, 1831.
Travels to South America, observes giant tortoises, finches,
and fossils of large extinct mammals
Evolution was originally termed, “transmutation” – the change
of one species to another. (original proponents were antiChristian – no doubt giving rise to opposition persistent today)
Natural Selection
Darwin realizes the key to evolution is
“natural selection”.


What is Evolution?
A change in the genetic structure
of a population. The term is also
frequently used to refer to the
appearance of a new species
Natural Selection
1.
2.
3.
4.
All species are capable of
producing offspring at a faster rate
than food supplies increase.
There is biological variation within
all species
Each generation produces more
offspring than can survive; there is
competition among individuals.
Individuals who have favorable
traits or variations have an
advantage over those who don’t.
(i.e. fitness)
Natural Selection
5.
6.
7.
The environmental context
determines whether a trait is
favorable.
Traits are inherited and passed on
to the next generation.
Over long periods of geologic
time, successful variations
accumulate in a population, so that
later generations may be distinct
from ancestral ones. In time, a new
species may occur
Natural Selection
8.
Geographical isolation also
contributes to the formation of
new species. As species
become geographically
isolated, they begin to adapt
to different environments. Over
time, populations respond to
selective pressures.
Selective pressures: Forces in
the environment that influence
reproductive success in
individuals.
Natural Selection in Action

Peppered Moths of
Britain
Natural Selection in Action

Resistant strains of disease
causing microorganisms in
humans
1940’s – introduction of
antibiotics
 Bacteria possesses genetic
variability
 Bacteria produces new
generation every few
hours

Natural Selection in Action

1.
2.
3.
4.
Fundamentals of Evolutionary
Change:
A trait must be inherited if
evolution is to act on it.
Natural selection can’t occur
without population variation in
inherited characteristics
Fitness is a relative measure that
changes as the environment
changes.
Natural selection can act only on
traits that affect reproduction.
 Fertility is important- more
births = more genes passed on.
Constraints on 19th Century Evolutionary
Theory

Darwin argued for the concept of evolution – in
general –
 He
didn’t know the exact mechanisms of change
 He didn’t know the source of variation
 He believed inheritance was a blending process by
parents to offspring
Constraints on 19th Century Evolutionary
Theory

20th Century:
Gregor Mendel’s (Austrian
monk) and Darwin’s theory of
natural selection come together
 1953 – Watson and Crick –
discover DNA
 New discoveries: sequencing of
the human genome
 Entire genetic makeup of an
individual or species

Opposition to Evolution Today

Debate over Evolution continues….
Religion and science concern
different aspects of the human
experience
There aren’t simple answers to
complex questions


As biological organisms we are subject to evolution, variation, and
adaptation
Physical Anthropology is in part human biology seen from an
evolutionary perspective
 Macro evolution – large scale changes that happen over
successive generations
 Micro evolution – small genetic changes that occur within a
species