Transcript Lab 1 - CLAS Users

ANT 3514 – Intro to Bio Anth
Lab
Megan Hosford
[email protected]
B329 and B301
MWR (2:00-3:15)
ANT 3415C Lab Policies
Rules for Turlington B304
NO food or drinks allowed in the room.
NO cell phones or pagers during lab session – these must be turned off.
Handle and treat all teaching materials in the room with utmost care and respect. Bone and fossil casts are breakable
(and expensive)!
COURSE WEBSITE
www.clas.ufl.edu/users/krigbaum/3514
Attendance
Lab sessions are MANDITORY. Attendance will be taken at the beginning of each session. If you plan on missing a lab,
you must notify your TA at the beginning of the week and you must have a legitimate reason. The TA will place you into
another appropriate session for that week. There will be no lab make-up opportunities except under the following
situations: (1) serious sickness/injury with official doctor/infirmary letter to Prof. Krigbaum; (2) military or athletic excuses
with official documents; (3) other emergencies (talk to your TA or the Prof. Krigbaum for approval).
Grading
There will be 6 lab sessions (20 points each) and 3 lab quizzes (2 in-class and 1 take-home, 10 points each). The three
lab quizzes will be given BEFORE exams. Lab homework is due at the beginning of next week’s lab. Lab questions will be
drawn from reading materials as well as those based on materials provided during lab hours and lecture. You may turn in
the answers of a lab you missed, but answers for in-lab questions will NOT be credited.
Lab 1
Principles of Evolution
Part 1: Natural
Selection
Evolution
The change in gene frequency over time.
Natural Selection –
The mechanism that determines:
1. which characteristics (physical or behavioral) are
best suited to the environment
2. will persist in succeeding generations, given a
stable environment
3. advantageous characters become numerous in
future populations at the expense of less
favorable characteristics
Measuring ‘fitness’
► Natural
selection acts on genetic variation
so that the genes for ‘fit’ phenotypes
increase in a population.
Who is the most fit?
1. A professional athlete (7-digit income) who is in good
health, single, and has no children.
2. A single parent (minimum wage income) who is in fair
health and struggling to raise 2 children.
3. A foster parent (modest income) who is in good health
and parenting an adopted child.
Lamarkian vs. Darwinian Evolution
(LOOK AT QU 1-3)
Lamark (~1800)
►
►
►
►
►
Variation exists b/c of environment, in response to a specific
demand
An individual’s efforts affected its physical structure  inherited
Individual level
Goal – oriented
Directionality
Darwin (1859)
•Variation naturally exists
•Offspring inherent characteristics from parents
•Depending on environment, some characteristics more
beneficial than others
•Population level
•Not goal – oriented
•No directionality
Darwin’s War
Randomized gene pool
► Each person maintains a population of 10 individuals
► In this environment, higher-ranking cards are being
selected for, aces represent the suite of characteristics
best suited for this current environment
► Play war, randomly select competition – keep ‘fit’ cards,
replace ‘unfit’ ones
► At the end of 10 rounds (generations), see how final
population is different from your original population
► Record population demography prior to each round
(Round 1 is your original hand)
► Hand in data sheet, I will email class population results
►
Lab 1, Part 2:
Cell Biology and
Genetics
DNA Structure
Deoxyribonucleic acid
Main component of chromosomes
Double-stranded molecule
Contains genetic codes
Synthesizes protein
Made of two chains of nuclieotides—
sugar, phosphate, base (A,T,C,G)
LOOK AT QUESTION 7
Terminology
Gene
Chromosome
autosome & sex chromosome
Allele
Diploid & haploid
Cell Division
Mitosissomatic cell DNA replication
simple cell division (1 into 2)
exact replication of the original DNA
Cell Division
Meiosissex cell DNA replication in ovary & testis
2 divisions (1 into 4)
random assortment
recombination (cross-over)
gamete
Mendelian Genetics
Gregor Mendel (1822-1884)
Dominance vs. Recessiveness
Homozygous vs. Heterozygous
Medelian traits
Principle of Segregation
Principle of Independent Assortment
(LOOK AT QUESTION 11)
Principle of Segregation: Genes (alleles) occur
in pairs (because chromosomes occur in pairs).
During gamete production, the members of
each gene pair separate, so that each gamete
contains one member of each pair. During
fertilization, the full number of chromosomes is
restored, and members of gene or allele pairs
are reunited.
Principle of Independent Assortment: The
distribution of one pair of alleles into gametes
does not influence the distribution of another
pair. The genes controlling different traits are
inherited independently of one another.
LOOK AT QUESTION 8
Lab 1, Part 3:
Forces of Evolution
Evolution – change in gene frequency over time
 acts on a population
Forces of Evolution - factors that produce and
redistribute variation:
1. Natural Selection
2. Gene Flow
3. Genetic Drift
4. Mutation
(Recombination)
(LOOK AT QUESTION 13)
Gene Flow
The exchange of genes between populations
- migrations (group or individual-level)
Inherent mechanism within human and non-human
species
- Social
taboos against incest
- Fundamental basis for sex-specific patterns of philopatry
& migration
Genetic Drift
(LOOK AT QUESTION 15)
Changes in allele frequencies due to:
► Random factors
► Small population size
• Founder effect – prevents gene flow 
genetic bottleneck
- colonization
- disasters
Examples:
- Cheetahs – decreased reproductive potential
- Taiwanese macaques – geographic isolation
Mutation
► Changes
of alleles, A
a
► Mutation rates are usually low in big pop’
► Natural selection determines the frequency
of the mutated allele
► Basic creative force in evolution—the ONLY
way to produce new genetic variation
► LOOK
AT QUESTION 14
Types of Selection
► 1.
Stabilizing:
when environment is stable, maintains
genotypic and phenotypic status quo
► 2. Directional:
responses to environmental change and
productive shifts in composition of a population’s
gene pool and collective phenotypes
LOOK AT QUESTION 9 and 16!
Hardy-Weinberg Theorem
► Predicts
the distribution of genotypes in
subsequent generations of a population
► p2+2pq+q2=1,
where
p2 : % homozygous dominant
2pq : % heterozygous
q2 : % homozygous recessive
LOOK AT QUESTION 17
Hardy-Weinberg Theorem
Assumptions:
►A
large population
► Random mating
► Equal numbers of males and females
► Absence of natural selection
► No mutation, genetic drift or gene flow
► No migration in or out
What will happen if H-W Theorem holds?
Species Concepts
► Biological
Species Concept – a group of individuals
capable of producing fertile offspring
 Based on gene flow and reproductive isolation
 Limitations?
Doesn’t allow for hybrids (e.g. baboons)
Reproductive behavior can’t be traced through the fossil record
• Ecological
Species Concept – a group of organisms
exploiting a single niche
- Stresses
the role of natural selection
- Limitations?
Does a niche define a species, or does a species define a niche?
No easy answer – not necessarily mutually exclusive!
READ QUESTION 18 AND
LISTEN CAREFULLY ABOUT
THE NEXT THREE SLIDES
Speciation
► The
process by which a new species evolves
from a prior species
► The
most basic process in macroevolution
Speciation
► Anagenesis: one species evolves into another
A
B
► Cladogenesis: ancestral species evolves into
branches of descendent species
A
B
A’
Models of Speciation
► Gradualism:
New species evolves by gradual changes from the
original one
► Punctuating
equilibrium:
Not unidirectional