Discussion Forum–Anthropology 1(need high quality assignment!!)

the discussion question :

How do you see Sexual Selection playing out in Modern Humans?  Where/how do you see the concepts of competition/display and choice in the biological traits or behaviors of humans?

Be sure you have read all of the instructions and etiquette guidelines under the General Information section of this course.

(please watch 3 of the films and also use chapter 2 chapter 3 ppt ‘s context to answer the question )

need at least 300 words 

Required Viewing: These films will be testable material as well as required viewing to answer the weekly discussion board question.

Evolution

What is Natural Selection?

Sexual Selection Explained

The Development of Evolutionary Theory

Anthropology 1: Fall 2016

 Religion and science concern different aspects of
the human experience, and they are not
inherently mutually exclusive categories

.

 Belief in God does not exclude the possibility of
biological

evolution

; acknowledgement of
evolutionary processes doesn’t preclude the
existence of God.

 Evolutionary theories are not rejected by all
religions or by most forms of Christianity.

 A substantial majority of Americans (about 7 in 10)
believe the scientific Theory of Evolution is
compatible with a belief in God – one does not
preclude the other.
◦ “Evolution and Creationism in Public Education” People For the American Way Foundation

 Evolution is the most fundamental of all biological
processes, but one of the most misunderstood.

 Humans evolved from a species that lived some 6-8
million years ago (mya), not monkeys or chimpanzees.

 Humans do share a recent common ancestor with other
primates

 Evolution takes time; hence, the appearance of a new
species is rarely witnessed

 The theory has been tested and subjected to
verification through accumulated evidence (and has
not been disproved)

 The theory of evolution has been supported by a
mounting body of genetic evidence.

 The theory has stood the test of time.

 The theory continues to grow.

 Evolutionary principles were developed in
western Europe, made possible by scientific
thinking dating to the 16th century.

 Western science, however, borrowed ideas from
Arab, Indian, and Chinese cultures where notions
of biological evolution had already developed.

 By the 19th century, evolution wasn’t a new
concept, but Natural Selection was a new theory

 The notion that species,
once created, can never
change

 An idea diametrically
opposed to theories of
biological evolution.

 To challenge the idea
was to challenge the
Argument from Design
(life engineered by a
purposeful God).

 Came with the discovery of the New World,
introducing new ideas and challenging
fundamental views about the planet.

 Exposure to new plants and animals
increased awareness of biological diversity.

 Brave new thinkers began to challenge long held
church doctrine and belief

◦ Aristotle taught that the sun and planets existed in a
series of concentric spheres that revolved around the
sun.

◦ Copernicus challenged the idea that the earth was the
center of the universe.

◦ Galileo’s work supported the idea that the universe was
a place of motion.

 John Ray, developed the concept of species.

 Groups of plants and animals could be
differentiated from other groups by their ability
to mate with one another and produce offspring.

 He placed such groups of reproductively isolated
organisms into a single category, which he called
the species.

 Carolus Linnaeus, a Swedish naturalist who
developed a method of classifying plants and
animals.

 In Systema Naturae, first published in 1735, he
standardized Ray’s use of genus and species
terminology and established the system of binomial
nomenclature.

 He added two more categories: class and order.

 Linnaeus’ four-level system became the basis for
taxonomy.

 Erasmus Darwin, Charles Darwin’s grandfather

 Physician, poet, and leading member of an
intellectual community in England

 In a poem, expressed the view that life had
originated in the seas and all species descended
from a common ancestor.

 Charles read his grandfather’s writings, but how
much he was influenced by them is unknown.

 Jean-Baptiste Lamarck developed a theory to
explain the evolutionary process, known as the
Inheritance of Acquired Characteristics.

◦ An example is the giraffe: having stripped the leaves
from the lower branches of a tree, the animal tries to
reach leaves on upper branches.

◦ The neck becomes slightly longer.

◦ The longer neck is passed on to offspring.

 Individual changes, transmits that change to
offspring

 An opponent to Lamarck,
Cuvier explained the fossil
record as the result of a
succession of catastrophes
followed by new creation
events.

 The view that the earth’s
geological landscape is the
result of violent cataclysmic
events.

 A lawyer, geologist, and, Charles Darwin’s
friend and mentor.

 Before meeting Darwin in 1836, Lyell had
earned acceptance in Europe’s most
prestigious scientific circles, thanks to his
praised Principles of Geology, published during
the years 1830–1833.

 The theory that the earth’s features are the
result of long-term natural processes that
continue to operate in the present as they did in
the past.

 Not a new idea, proposed by James Hutton, but
actually explained by Lyell, this theory opposed
catastrophism and contributed strongly to the
concept of immense geological time.

 Inspired both Charles Darwin and Alfred Wallace
in their separate discoveries of natural selection.

 Was arguing for limits of human population
growth, not concerned with how species change.

 Available resources set the limits for human
population growth

 This idea was extended to all organisms by
Darwin and Wallace.

Thomas Malthus and Principles of
Population

 Ideas were formed while
serving as a naturalist on
the 5-year voyage of the
HMS Beagle.

 Darwin saw the importance
of biological variation
within a species.

 Recognized that sexual
reproduction increased
variation, but did not yet
know why.

 The idea that in each generation more offspring
are born than survive to adulthood, coupled with
the notions of competition for resources and
biological diversity led to the theory of evolution.

 He wrote,“ It at once struck me that under these
circumstances favorable variations would tend to
be preserved, and unfavorable ones to be
destroyed.”

 Suggested species descended from other
species and new species were influenced
by environmental factors.

 Presented joint paper, coauthored with
Darwin, on evolution and natural
selection to the Linnean Society of
London

 Darwin published “On the origin of Species by
Means of Natural Selection, or the Preservation of
Favoured Races in the Struggle for Life” in 1959 in
a rush to the press to beat Wallace publishing on
Natural Selection first.
◦ Processes of Natural Selection,

are “the key” to understanding

evolution

 Pertaining to natural selection, a measure of
relative reproductive success of individuals.

 Fitness can be measured by an individual’s
genetic contribution to the next generation
compared to that of other individuals.

 The ability to conceive and produce healthy
offspring.

 An animal that gives birth to more young passes
its genes on a faster rate than one that bears few
offspring.

 An important element, however, is also the
number of young raised successfully to the point
where they reproduce, or differential net
reproductive success.

1. All species reproduce faster rate than food
supplies can increase.

2. There is biological variation within all species.

3. In each generation more individuals are
produced than can survive, and because of limited
resources, there is competition among individuals.

4. Individuals possessing favorable variations or
traits (i.e. speed, resistance to disease,
protective coloration) have an advantage over
those who do not.

 They have greater fitness because their
traits increase the likelihood they will survive
and reproduce.

5. The environment will determine if a trait is
beneficial.

◦ Geographical isolation (distance, natural barriers such
as oceans) contributes to the formation of new species
as individuals begin to adapt to different environments.

◦ Selective pressures (differential ecological
circumstances) cause distinct species to develop. The
13 species of Galápagos finches presumably all
descended from a common South American ancestor.

.

Natural Selection cont.

6. Traits are inherited and passed on to the next
generation. Individuals who produce more offspring
are said to have a greater reproductive success, or
fitness.

7. Variations accumulate over long periods of time,
so later generations may be distinct from ancestral
ones.

8. As populations respond to pressures over time,
they may become distinct species, descended from
a common ancestor.

1. A trait must be inherited if natural selection is
to act on it.

2. Natural selection can’t occur without
population variation in inherited
characteristics.

3. Fitness is a relative measure that changes as
the environment changes.

4. Natural selection can only act on traits that
affect reproduction.

 Our aggressive methods to fight microbes
will lead to modified micro-organisms that
have evolved to resist therapies such as
antibiotics.
 Use of antibiotics to treat bacterial infections weed

out vulnerable microbes, but leave less vulnerable
to reproduce. Less vulnerable cause more serious
forms of disease than the organisms that were
eliminated.

Example: HINI Flu viruses are the result of
viruses “evolving” or changing in form.

 Medical researchers try to predict which of
several strains will pose the most serious
threat and try to develop a vaccine that
targets that specific “evolving” strain.

 If future physicians and researchers don’t
understand evolution, there is little hope
they can forestall potential medical crises
as the pace of change in pathogens
exceeds that of the antibiotics designed to
defeat them.

T H E B I O L O G I C A L B A S I S O F L I F E

CHAPTER 3
ANTH 1 FALL 2016

THE CELL

• Cells are the basic units of life in all living
organisms.

• From single celled bacteria to us!

• An adult human has of perhaps as many as
1 trillion cells, all working together and
serving their unique purpose

CELLS

CELLS

• Life on earth can be traced back 3.7 billion years

to single celled organisms, such as bacteria and

blue-green algae.

• Eukaryotic cells, cells with a nucleus, appeared 1.2

billion years ago.

• A three-dimensional structure composed of carbohydrates,

lipids (fats), nucleic acids, and proteins

CELLS

• Somatic cells – cellular components of body

tissues, such as muscle, bone, skin, nerve, heart,

and brain

• Gametes – sex cells involved in reproduction and

not important as structural components of the

body

• Egg cells produced in female ovaries

• Sperm cells produced n male testes

• Zygote – union of sex cells to form the potential of

developing into a new individual; in this way gametes

transmit genetic information from parent to offspring.

CELL NUCLEUS

• A discrete unit surrounded by a thin membrane, called

the nuclear membrane.

• Inside are two kinds of nucleic acids,

DNA(deoxyribonucleic acid) and RNA (ribonucleic acid)

• Molecules that contain genetic

information that controls the cell’s

function.

CYTOPLASM

• Surrounds the nucleus

• Contains organelles involved in various activities, such

as breaking down nutrients and converting them to

other substances, storing and releasing energy,

releasing waste,

• This is where the manufacturing proteins of proteins or

protein synthesis occurs.

ORGANELLES

• Mitochondria – oval structures enclosed within a folded

membrane, containing their own distinct DNA, called

mitochondrial DNA (mtDNA), produce energy

• Ribosomes – roughly symmetrical and partly composed of

RNA; essential in protein synthesis

DNA STRUCTURE
• Cellular function and an organism’s inheritance

depends on the structure and function of DNA.

• DNA is composed of two chains of nucleotides,

comprising a double strand or double helix.

• A nucleotide consists of a sugar, a phosphate, and

one of four nitrogenous bases.

DNA STRUCTURE
• Nucleotides form long chains.

• The two chains are held together by bonds formed on
their bases with their complement on the other chain.
• Adenine (A) is the complement of Thymine(T)

• Guanine(G) is the complement of Cytosine(C)

• These two bases are said to be complementary because one

requires the other to form a complete DNA base and can only

bond A/T and G/C.

PART OF A DNA MOLECULE

ENZYMES

• Specialized proteins that initiate and direct

chemical reactions in

the body

.

• Replication begins when enzymes break the bonds

between bases throughout the DNA molecule,

separating two previously joined strands of

nucleotides and leaving their bases exposed.

DNA REPLICATION

THE DNA REPLICATION PROCESS

1. Enzymes break the bonds between the DNA

molecule.

2. Two nucleotide chains serve as templates for the

formation of a new strand of nucleotides.

3. Unattached nucleotides pair with the appropriate

complementary nucleotide.

PROTEIN SYNTHESIS: AMINO ACIDS

• Small molecules that are the components of

proteins.

• Amino acids are the building blocks of protein.

• Proteins differ according to number of amino acids

and the sequence in which they are arranged

PROTEINS

• Complex, three dimensional molecules that

function through their ability to bind to other

molecules

• The protein hemoglobin, found in red blood cells, is

able to bind to oxygen, which carries it throughout

the body

HORMONES

• Substances (usually proteins) that are produced by

specialized cells and travel to other parts of the

body, where they influence chemical reactions and

regulate various cellular functions.

PROTEIN SYNTHESIS

• Ribosomes help convert the genetic message from

the DNA into proteins.

• Messenger RNA (mRNA) carries the genetic

message from the cell nucleus to the ribosome.

• Transfer RNA (tRNA),found in the cytoplasm, binds to

one specific amino acid.

RNA AND DNA

RNA differs from DNA in three important ways:

1. It’s usually single-stranded. (This is true of

the forms we discuss, but it’s not true for

all.)

2. It contains a different type of sugar.

3. It contains the base uracil as a substitute

for the DNA base thymine. (Uracil is

attracted to adenine, just as thymine is.)

MESSENGER RNA (MRNA)

• A form of RNA that’s assembled on a sequence of

DNA bases.

• It carries the DNA code to the ribosome during

protein

synthesis.

TRANSFER RNA (TRNA)

• The type of RNA that binds to amino acids and

transports them to the ribosome during protein

synthesis.

PROTEIN SYNTHESIS:

TRANSCRIPTION

• The process of coding a genetic message for a

particular protein.

• A portion of the DNA unwinds and serves as a

template for the formation of a mRNA strand.

TRANSCRIPTION

• The two DNA strands have partly separated.

• Free messenger RNA (mRNA) nucleotides

have been drawn to the template strand,

and a strand of mRNA is being made.

• Note that the mRNA strand will exactly

complement the DNA template strand,

except that uracil (U) replaces thymine (T).

TRANSCRIPTION

PROTEIN SYNTHESIS:
TRANSLATION

• The mRNA travels through the nuclear
membrane to the ribosome.

• tRNAs arrive at the ribosome carrying their
specific amino acids.

• The base triplets on the tRNA match up with the
codons on the mRNA.

• As each tRNA line up in the sequence of mRNA
codons their amino acids link to form a protein.

WHAT IS A GENE?

• A gene is the entire sequence of DNA bases
responsible for the synthesis of a protein.

• A mutation occurs when the sequence of
bases in a gene is altered.

• Mutations may interfere with the ability to
produce vital protein and may lead to a
new variety within the species, hence,
evolution.

GENETICS

• The study of gene structure and action, and the

patterns of inheritance of traits from parent to

offspring.

• Genetic mechanisms are the foundation for

evolutionary change.

REGULATORY GENES

• Genes that code for the production of proteins that

can bind to DNA and modify the action of genes.

• Many are active only during certain stages of

development.

HOMEOBOX GENES (HOX GENES)

• An evolutionarily ancient family of regulatory genes

(highly conserved) that determines the

development of the overall organism i.e.. body

shape size and the unique body tissue such as

organs.

VERTEBRAE AND HOX GENES

• The cervical vertebrae (a) have characteristics
that differentiate them from the thoracic vertebrae
(b) attached to the ribs, and the lumbar vertebrae
(c) of the lower back.

• Hox genes determine the overall pattern of each
type of vertebra and of each individual vertebra.

CELL DIVISION

• Cell division results in production of new cells.

• During cell division:
• Cells are involved with normal cellular and metabolic

processes.

• The cell’s DNA becomes tightly coiled.

• DNA is visible under a microscope as chromosomes.

CHROMOSOMES

• Scanning electron
micrograph of
human
chromosomes
during cell division.

• Note that these

chromosomes are

composed of two
strands, or two DNA
molecules.

CHROMOSOME STRUCTURE

• A chromosome is composed of DNA and
associated proteins.

• During normal cell functions, chromosomes exist
as single-stranded structures.

• During cell division, chromosomes consist of two
strands of DNA joined at the centromere.

• Since the DNA molecules have replicated, one
strand of a chromosome is an exact copy of the
other.

CHROMOSOMES AND GENETICS

• Each species is characterized by a specific
number of chromosomes.
• Humans have 46 chromosomes.

• 23 from each parent

• Chromosome pairs are called homologus:
• They carry genetic information that influences the

same traits.

• They are not genetically identical.

TYPES OF CHROMOSOMES

• Autosomes – govern all physical characteristics except
sex determination.

• Sex chromosomes – X and Y chromosome.

• Mammal females have two X chromosomes.

• Mammal males have one X and one Y chromosome.

MITOSIS

• Mitosis is cell division in somatic cells.

• Mitosis occurs during growth and repair/ replacement
of tissues.

• The result of mitosis is two identical daughter cells that

are genetically identical to the original

cell.

STEPS IN MITOSIS

1. The 46 chromosomes line up in

the center of the

cell.

2. The chromosomes are pulled apart at the
centromere.

3. The strands separate and move

to opposite ends of

the dividing cell.

4. The cell membrane pinches in and two new cells
exist.

MITOSIS

• The cell is involved

in metabolic

activities.

• DNA replication

occurs, but

chromosomes are

not

visible.

MITOSIS

• The nuclear

membrane

disappears, and

double-stranded

chromosomes are
visible.

MITOSIS

• The chromosomes

align themselves at

the center of the
cell.

MITOSIS
• The chromosomes

split at the

centromere, and

the strands

separate and move

to opposite ends of
the dividing cell.

MITOSIS

• The cell membrane

pinches in as the

cell continues to

divide.

• The chromosomes

begin to uncoil (not

shown here).

MITOSIS

• After mitosis is

complete, there

are two identical

daughter cells.

• The nuclear

membrane is

present, and

chromosomes are

no longer visible.

MEIOSIS

• Cell division in specialized cells in ovaries and testes.

• Meiosis involves two divisions and results in four

daughter cells, each containing only half the original

number of chromosomes.

• These cells can develop into gametes.

MEIOSIS

RECOMBINATION

• Sometimes called crossing over; the sharing of some

genetic material between partner chromosomes

during meiosis.

EVOLUTIONARY
SIGNIFICANCE OF MEIOSIS

• Meiosis and sexual reproduction are highly important
evolutionary innovations.

• Meiosis increases genetic variation at a faster rate
than mutation.

• Offspring in sexually reproducing species represent the

combination of genetic information from two parents.

PROBLEMS WITH MEIOSIS

• In order for fetal development to occur normally, the

meiotic process needs to be exact

• If chromosomes or chromosome strands do not

separate during either of the two divisions, serious

problems can develop

• Failure to separate is called nondisjunction

POLYMERASE CHAIN REACTION
(PCR)

• Allows scientists to make of copies of DNA
samples which can then be analyzed.

• Scientists use PCR to:

• Examine nucleotide sequences in
Neandertal fossils and Egyptian mummies

• Identify individuals in the case of remains,
crime or family relation.

DNA FINGERPRINTS

• Eight DNA fingerprints,

one of which is from a

blood sample left at

an actual crime scene.

• The other seven are

from suspects.

• By comparing the

banding patterns, it is

easy to identify the

guilty person.

RECOMBINANT DNA TECHNOLOGY

• A process in which genes from the cell of one

species are transferred to somatic cells or gametes

of another species.

• Production of human gene products such as insulin

• Genetic manipulation

CLONES

• Organisms that are genetically identical to another

organism.

• The term may also be used in referring to

genetically identical DNA segments, molecules,

and cells.

HUMAN GENOME PROJECT

• Effort begun in 1990 to sequence the entire human

genome, which consists of some 3 billion bases

comprising approximately 25,000 to 30,000 genes.

• The goal was achieved in 2003.

• Scientists are still several years away from identifying

the functions of many of the proteins produced by

these genes.