Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

BIO 110
Monday, January 5, 2015
CHAPTER ONE


Science only attempts to show things we can see, hear, etc
...
5%)
3) Hydrogen (9
...
1%) of 15 other elements are also found in the body



Electron shells
-electrons move around the nucleus in designated areas called electron shells
-an atom can have as many as 7 electron shells in total
*First electron shell capacity: 2 electrons
*Second electron shell capacity: 8 electrons



Unstable atoms: hydrogen and nitrogen



Stable atoms: helium and neon



Ions are charged atoms



Atom that loses one or more electrons become positively charged, while an atom that

acquires electrons becomes negatively charged


Ionic bonds

-One atom transfers one or more electrons completely to another
-the result is two oppositely charged ions
-the 2 oppositely charged ions attract each other, forming a compound


Covalent bonds (sharing of electrons)

-an atom of hydrogen has one electron in 1st shell; one more electron is needed to fill the shell
-the nuclei of 2 hydrogen atoms come closer together and share the 2 electrons, which circle
around both of them; the new H2 makeup is more stable
-2 pairs of electrons are shared between 2 oxygen atoms

Tuesday, January 6, 2015
CHAPTER TWO CONTINUED


Nucleic Acids (in DNA)

-polymers
-nucleotide: made up of a sugar-phosphate backbone (a phosphate group and a sugar
molecule) and 1 of 4 nitrogen-containing bases (adenine, thymine, guanine, cytosine)
-strand of DNA (DNA is a double-helix, a corkscrew type shape)
In DNA, adenine always pairs with thymine, and guanine always pairs with cytosine, so if
you have one strand, you can build the other strand (one is template; other is complementary
strand)


Ribonucleic acid (RNA)

-RNA structure: There are 3 important structural differences between RNA and DNA
...

2) RNA has only one sugar-phosphate backbone, while DNA has two
...


-RNA function: RNA acts as a middleman molecule
...

-DNA to RNA to protein (central dogma of molecular biology)


Lipids (not a polymer)

-typical features of lipids:
1) Nonpolar molecules that do not dissolve in water
2) Greasy to the touch
3) Can be significant source of energy storage
-3 types of lipids:
1) Fats (function: long-term energy storage, cushioning, and insulation)
2) Sterols (function: regulate growth and development; generally hormones)
3) Phospholipids (function: for cellular membranes)
-Fats store such large amounts of energy, a strong taste preference for fats over other energy
sources has evolved in animals
...

-Straight fatty acids can be packed together tightly
...
\
-Saturated fats can pack nicely into ?
-In unsaturated fats, at least one carbon in the hydrocarbon chain is bound to just one
hydrogen, causing the fatty acid to have a crooked shape
...
As a result, unsaturated fats on their
own (such as olive oil) are liquid at room temp
...
This
can improve a food’s taste, texture, and shelf-life
...

*unsaturated fatty acid- cis form
*partially hydrogenated trans fatty acid- trans form) – avoid them
*Hydrogenation converts some double bonds to single bonds, but it adds hydrogens in the
less healthful “trans” position, which changes the orientation of the double bond
...

-Sterols
-Cholesterol
*important component of cell membranes in animals
*dietary cholesterol can attach to and thicken vessel walls and may cause serious health
problems
*sterols are ball based on a structure featuring four fused carbon rings
-Steroid hormones
*regulate sexual development, maturation, and sex cell production
*estrogen influences memory and mood
*testosterone stimulates muscle growth
-Phospholipids
-Phospholipids align so that their hydrophilic heads extend toward the water, while their
hydrophobic tails are directed away from the water
...


CHAPTER THREE


Cell Theory:

1) All living organisms are made up of cells
...


3) Everything an organism does begins and is done at the cellular level
...
Eukaryotes (has a true nucleus)
-Karyon- Greek= kernel (referring to the nucleus)
-Pro- Greek= before
-Eu- Greek= true
-The Prokaryote basic structure—google pictures
-similar:
*both have ribosomes (make proteins)
*cytoplasm
*plasma membrane
*DNA
*some have cell wall
-different:
*euks—have nucleus
*euks—have organelles that are bounded by membranes
*euks—are about 10 times larger than proks
*proks are all single-cell; euks can be single-celled or multi-cellular
-another name for prokaryotes: bacteria
-eukaryotes are everybody who is not a bacterium
-structure not found in plant cells: centriole
-structures not found in animal cells: chloroplast, cell wall, vacuole
 Molecules within the plasma membrane (fluid-mosaic model)
-extracellular fluid, carbs, plasma membrane, lipids, surface proteins, transmembrane protein,
intracellular fluid
-function of plasma membrane molecules:
*carbohydrate chains: provide a “fingerprint” for the cell, so it can be recognized by other
cells
*cholesterol: helps the membrane retain its flexibility
*receptor proteins: bind to external chemicals in order to regulate processes w/in the cell
*recognition proteins: provide a “fingerprint” for the cell, so it can by recognized by other
cells

*transport proteins: provides a passageway for molecules to travel into and out of the cell
*enzymatic proteins: accelerate intracellular and extracellular reactions on the plasma
membrane
 2 different methods of transport: passive and active
-passive: occurs when molecules move across a membrane without energy input; molecules
move down their concentration gradients from a high cone to a low cone
Ex: putting die in a beaker and watching it diffuse
-simple diffusion: molecules pass directly through the plasma membrane without the assistance
of another molecule
Ex: CO2 can easily move across a membrane
-facilitated diffusion: molecules move across the plasma membrane with the help of a channel
or carrier molecule
-active: occurs when the movement of molecules into and out of a cell requires the input of
energy; moves against the concentrated gradient from a low concentration to a high
concentration
Ex: in response to eating, the cells lining your stomach use ATP to pump lage numbers of H+
ions into the stomach
-active transport in the stomach increases your ability to digest food


Endomembrane system

-within= “Endo”
-a group of organelles within the plasma membrane that work together


Nucleus

-functions:
1) acts as the genetic control center of the cell
2) stores hereditary information (DNA)
-nucleolus: area of the nucleus, where ribosomal subunits (made here) are assembled
-chromatin/chromosomes: thin fibers of DNA, which carry all hereditary information
-nuclear membrane: two bilayers, covered in pores, that surrounded the nucleus
-RNA gets out through pores
-separate packages are chromosomes; big packages are chromatin


Lysosomes (Lyse= “break”)

-function: act as floating garbage disposals for cells, digesting and recycling cellular waste
products and consumed material
-lysosome acts as the stomach and breaks down pieces used by the cell
-full of digestive enzymes and acid
-membrane to contain all the acid and enzymes
-phagocytosis (phago= to eat; cytosis= cell)


Rough Endoplasmic (Endo= within; plasmic= cytoplasm; reticulum- Latin= “little net”)

Reticulum (Rough ER)
-function: makes and modifies proteins that will be shipped to other locations in the
endomembrane system, the cell surface or outside the cell
...
Ribosomes are protein-making machines
...
121 for review of cell structures***


Not sure if chloroplasts or mitochondria came first

VIDEO (Cloning and Stem Cells)


First clone: Dolly



1997- successful cloning of three bull calves



Egg and sperm contain only half the information needed to reproduce



The zygote contains all the information needed
...




DNA is, for the most part, concentrated in the nucleus
...


VIDEO #2 (stem cells)


A blank cell has the potential to do anything other cells do but not until it has been given

instructions
...


Thursday, January 8, 2015
CHAPTER 14
ECOLOGY
 Eco= oikos= “home”/environment
 Logy= logos= “to study”
 Ecology- scientific study of the interactions between organisms and their environment;
multidisciplinary
-includes biotic and abiotic factors (biotic- living; abiotic- non-living)
 Levels of study:
-Organismal- have to know a little bit about the organism
-Population- group of individuals of same species living in same area
-Community- all organisms living in a particular area
Ex: squirrel
Population: squirrels at Augie
Community: squirrels at Augie plus the humans, grasses, plants, fleas, microbes
-Ecosystem- all organisms in an area and abiotic factors (precipitation, etc); also get into
things such as energy flow and nutrients that cycle
-Biosphere (ecosphere)- entire portion of Earth where living organisms exist and interact
with each other and their environment; global perspective
-pg
...
551
-even if growth rate is constant, population will increase since progeny of each generation are
added to base
-rate= amount/time
-generally cannot occur unchecked—increases change environment, declines follow
-carrying capacity (K): the maximum stable population size that a particular environment can
support over time; illustrated as an S-shaped curve
-pg
...
563)

Reproduction and survival: Big-bang reproducers such as salmon make a single
exceptionally high investment in reproduction, then die shortly afterward
...

Number and size of offspring: Female lizards of the species Uta stans-buriana produce
medium-sized eggs as compromise between a large number of small-sized eggs (with poor
survival of offspring), and few large-sized eggs (with better survival of offspring)
...

 Cohort= group of individuals born during same time interval
-boomers: 1946-1964 born
-Millennials: around the 2000’s?
HUMAN POPULATIONS
1
...

2
...
Growth very rapid since Industrial Revolution (late 1700s; machinery)
-mostly due to decreases in death rates
4
...
1 billion; estimated 8
...
Growth rates very among different countries
...
572
-pg
...
What is the carrying capacity of Earth for humans?
-food/water
-fuels
-wastes

-disease
-ecological footprint: measure of how fast we consume resources and generate waste
compared to how fast nature can absorb our waste and produce new resources
7
...
)
-Ecological niche (profession- what a species does): sum total of an organism’s use of its
resources; its ecological role
Niche features:
-the space an organism requires
-the type and amount of food an organism utilizes
-the timing of an organism’s reproduction
-an organism’s temperature and moisture requirements and other necessary living
Conditions
-the organisms for which it is a food source
-its influence on competitors
Fundamental niche- theoretical (what the organism can use)
Realized niche- actual (what an organism does use)
-Co-evolution: mutual evolutionary influence between 2 different species interacting with
each other and reciprocally influencing each other’s adaptations
Ex: as prey evolve, defensive traits are favored; as predators evolve, traits that overcome
prey’s defenses are favored
Example of co-evolution on page 602
-What types of interactions occur?
Competition: 2 individuals that have the same need; usually only over limited resources;
can be within a population or among populations; negative for all participants (even though

there’s competition with one winner, the fact that it had to compete is still going to be
ultimately harmful)
Competitive exclusion principle: if there are 2 species competing for the same,
limiting resources, one species will be more successful than the other, resulting in the
elimination of the less successful species
Complete competitors cannot co-exist (realized niches are the same)
-When niches overlap
1) When grown alone under a particular set of environmental conditions, each of two
similar Paramecium species thrives
...
606- physical defenses for reducing predation (mechanical defenses, chemical
defenses, warning coloration, camouflage, hiding or escaping, fighting back)
Not necessarily negative
Can have negative feedback effect
-parasitism (form of predation)
Participants:
1) Parasite- gains; can be endoparasite (endo=inside; parasite=host) or
ectoparasite (ecto= outside; parasite= host)
*Parasites are predators that benefit from a symbiotic relationship with their hosts
...

*The most successful parasites kill hosts slowly if at all

*parasites are often host specific, and may need >1 host
Life cycle
*Two-host life cycle of Plasmodium (causes malaria)
Host- mosquito Parasite- plasmodium
Host- human Parasite- Plasmodium (endo)/mosquito (ecto)
-symbiosis (bio- life/living; osis- process; sym- together): close association between 2 or more
species
1) Parasitism
2) Commensalism- rare; one benefits; one unaffected
Ex (pg
...

Ectomycorrhiaze- hyphae press closely against the outer side the the cell waslls of the roots
hairs
...
)
*decomposers- take material and make it even smaller (bacteria, fungi); recyclers
-Decomposers and detritivores break down organic wastes, releasing chemical
components that can then be reused by plants and other primary producers
...

1) Primary producers- Plants convert light energy from the sun into food through
photosynthesis
...

3) Secondary consumers- carnivores are animals that eat herbivores
...




Food chains vs webs



Productivity: amount of energy available to be passed between trophic levels



Biomass: dry weight of organic matter present



Trophic efficiency- ecosystem level:
-not all that is produced is consumed
-of what is consumed, not all converted to biomass (lost as heat, used as energy source, not
all digested)
-varies with specific type of ecosystem; averages ca
...
598
1
...

2
...

Organisms extract energy from carbon bonds and exhale carbon dioxide back into the
atmosphere as a by-product
...
) When large numbers of organisms die, carbon accumulates in the ground
...

4
...

-in atmosphere as N2 (not available to most organisms)
*atmosphere: 78% N2, 21% O2, rest: CO2, etc
...
599
-human inputs:
*(too many) fertilizers: may cause eutrophication (“true feeding”)
Eutrophication: the increase in nutrients in an ecosystem, particularly nitrogen
and phosphorus—often leads to the rapid growth of algae and bacteria in lakes and other
aquatic ecosystems; these organisms then consume much of the oxygen, leading to large dieoffs of animal life
...

“dead zone”= hypoxic zone
Area of gulf affected will ↑ or ↓with water flow/ ppt
**excess N or P fertilizers
*burning fossil fuels/wood:
**releases oxides of N and S (part of living organisms)
Pg
...

Cause: Burning fossil fuels releases sulfur dioxide and nitrogen
dioxide
...

Strategies for solution: Tighter regulation and reduction of sulfur
dioxide and nitrogen dioxide emission


Phosphorus P
-nucleic acids, phospholipids, ATP, etc
...
600- the phosphorus cycle



Water (hydrologic cycle) H2O
-cycles between Earth and atmosphere via:

Evaporation (liquid water to gaseous water), transpiration (movement of water through
plants; move from roots to leaves to atmosphere), and precipitation (water from atmosphere
to Earth)
-on land: may run-off, percolate (through soil, down below surface to be stored), be stored
Aquifer: underground lake or river


Toxins
-not biodegradable; accumulate (can’t easily be broken down by natural means)
-synergistic effects
-biomagnification (compounds can’t be broken down, can accumulate, and be magnified
through feeding relationships)

Monday, January 12, 2015


Ozone (O3

O=O-O)

-good or bad depending upon location
-in lower atm (troposphere)—is “bad”:
*is component of smog
*contributes to global warming (traps heat)
*respiratory problems
-in stratosphere—forms ozone layer: protects Earth from excess UV radiation (“good”)
*UV radiation can lead to: skin cancer, cataracts, negatively affect immune system
function, materials damaged (manufactured products)
-lack of stratospheric ozone= “ozone hole”:
*pg
...

*darkest blue= lowest amount O3
*decrease in # of molecules of O3 (O3→O2)
O=OxO

O2

*more UV reaches Earth
*depletion caused by chlorofluorocarbons (CFCs)
*has the problem been solved?

*does not cause global warming
BIOMES
-major types of ecosystems covering large geographical areas (often described in terms of
vegetation)
-mostly determined by climate: long term weather of an area
*average temperatures and precipitation
*seasonal variations/extremes
-affected globally by solar energy input, movements of Earth, ocean currents
-pg
...

590)
-species composition varies among biomes of the same type
-boundaries are not sharply defined (there are gradual transitions)
*pg
...
30 degrees N and S lat
...
America), pampas (S
...

Africa), steppes (Asia)


Forests
-tropical
*within tropics of cancer and Capricorn
*23
...
g; boreal- northern)
*largest terrestrial biome
*latitudes between temperature forests and tundra
*long, cold, dry winters and short, wet summers
*montane forests at all latitudes
-tundra
*arctic (near North Pole) and alpine (as you’re going up a mountain)
*permafrost
*low precipitation but wet soils
*low growing plants; animals migrate

(STUDY THESE ON THE MAP- forests relative to the map)

AQUATIC BIOMES


Freshwater- < 1% salt
-flowing and standing
-lakes: littoral (close to shore), limnetic (open water away from shore), photic (light), aphotic
(deeper water; below where light can penetrate), benthic zones (floor)
-waters do mix: turnover
-eutrophication



Wetlands and estuaries—when fresh H2O and salt H2O meet
-extremely important:
*pollution abatement (abatement- make it go away or make it less bad) “nature’s
kidneys”
*high diversity/breeding grounds
*water storage
*recreation0



Saltwater (oceans cover ~ 75% Earth)
-intertidal (inter=between) areas—affected by tides
-coral reefs—shallow, photic
-pelagic zone—open ocean, photic at surface; aphotic below
-benthic zone
Abyssal zone

BIODIVERSITY
-total of all the different species currently on Earth


Why important?
-represents all that has come before; once gone, is gone for good
-carries genetic basis for future evolution/adaptation
-resources
Pacific yew tree- ?
-aesthetics, recreation, religious, ethics
...

-species richness: number of species in an area
*About 1
...
630 ex: coral reefs (Philippines), islands (Madagascar)
-extinction is normal/natural—but rates increasing; much of what is being destroyed is
unknown!
-as habitats are destroyed, so are species
*habitat destruction is #1 cause of biodiversity loss

Humans have:
-simplified ecosystems (monoculture)
-overharvested potentially renewable resources
-introduced exotic species (ex: kudzu)
-emitted pollutants/toxins
-deforested vast areas
-pg
...
645- greenhouse effect: energy from the sun passes easily through the atmosphere to
warm earth’s surface
-greenhouse gases—absorb heat, reradiate it to Earth
- is natural effect; necessary for life as we know it
-problem: when greenhouse gases increase, more heat is trapped and less escapes → climate
warms
-greenhouse gases: H2O, CO2, O3, CH4, CFCs, others (know these!!!); methane (natural gas);
25 * heat trapped as CO2 traps; N2O nitrous oxide
-most important greenhouse gases: CO2

*sources: fossil fuel burning (coal, oil, gasoline)
Deforestation/land clearing/ burning
*in addition to increasing CO2 levels, Earth’s ability to deal with CO2 is decreasing
*CO2 levels have fluctuated for 1000’s of years; correlation with temperature
-global temperature increasing

IPCC (Intergovernmental Panel on Climate Change) VIDEO
-3 main working groups: physical aspects of climate change, biology (living organisms),
looking at how we’re solving the problem
-the CO2 concentrations have increased by 40%; emissions higher than they’ve been for the
last 8,000 years in history
-affecting agriculture and fresh water sources already
-it’s about inequalities that make people vulnerable to climate change
-the impacts of climate change will become progressively more difficult
-farmers are changing planting times to adapt
-construction of buildings is changing to adapt

Wednesday, January 14, 2015
****See handout with terms
...




Why do cells divide?
1) Repair damage/ replace old cells
2) Growth
3) Reproduction



Eukaryotic Cell Cycle (Figure 6
...
226 (5 steps)
1
...
) DNA synthesis (S) (2nd part of interphase)

Single chromosomes replicate to become sister chromatids
3
...
) Mitosis (1st sub-phase of mitotic phase)
5
...
228) (happening during S phase of interphase)
1) Unwinding- the coiled, double-stranded DNA molecule unwinds and separates into 2
strands
...
(“Enzymes make the
world go round
...




Mitosis Creates duplicate cells (pg
...

-Mitosis
1
...

2
...

3
...

4
...




Interphase (pg
...
(G2)



Mitosis (pg
...
) Prophase
-Nuclear membrane breaks down
...

-Spindle (made up of cytoskeletal fibers) forms
...
) Metaphase
-Sister chromatids line up at the center of the cell
...
) Anaphase (Ana= up/away/separate/cutting up)

-The sister chromatid pairs are pulled apart by the spindle fibers
...

4
...

-The cell beings to pinch in two
...




In animals, they have to pass the G1 checkpoint
...
If a cell doesn’t receive it, the cell exits the cell cycle and goes into G0, a non-dividing
state
...
(figure 6-12)
-breaking contact inhibition= tumor
-break anchorage dependence= metastasis (how cancer is spread); cancer cells divide
indefinitely
-break “rule” of cell death by being immortal (cells are generally essentially programmed to
death-- Every time a cell divides, the telomere gets shorter
...
) For cancer
cells, the telomere gets a little shorter and then grow a little bit, thus the cancer cell can go on
and on
...

-Cancer cells have reduced “stickiness
...
240)
-Interphase: Each chromosome in a homologous pair replicates to form a sister
chromatid
...


-Meiosis 2: In the second division of meiosis, the sister chromatids separate
...

**see pg
...

-Reassortment of homologues- the homologues and sister chromatids distributed to each
daughter cell during meiosis are a random mix of maternal and paternal genetic material;
possible # of different gametes= over 8 million



Why is variation important?
-EVOLUTION



Mutations
-pg
...
) Variation (inheritance itself is necessary for evolution)
2
...
) Permits advantageous traits to be passed to the next generation


What is inheritance?

-The ability to pass on traits
...

DNA “codes” for traits
...
These instructions can result in different versions of the same trait
...
(Crossing=reproduce together)
-Then, Mendel crossed two of the purple-flower offspring
...



Mendel’s Law of Segregation
-Adult Plant

Adult Plant

*True-breeding Purple

*White

*Got two genes from parent

*Got two genes from parent

*Both of genes it inherited

*Got two white genes from its parents

coded for purple

*Make gametes

*Make gametes
Process of fertilization
One purple, one white
(offspring of 2 true-breeding parents)
Heterozygote


Figure 7
...
At fertilization, offspring receive from each parent one allele for each gene
...
) Complete dominance- Mendel’s peas (Heterozygote look like homozygous
dominant
...

Ex: Polydactyly (6 fingers), Achondroplastic dwarfism
2
...
) Co-dominance- each allele is fully expressed
Ex: human blood types
4
...
) Polygenic traits—coded for by more than one gene
Ex: height, skin color
6
...
) Linkage- the tendency for two genes on the same chromosome to be inherited
together (Figure 7-29)
Ex: red hair and freckles
8
...
) Environmental Effects (nature vs
...



Autosomal traits—the genes are located on non-sex chromosomes (autosome= nonsex chromosomes)



Sex-linked traits—the genes are located on sex-chromosomes (X and Y; mainly X)
-Genes on Y:
SRY complex that are involved in being male
-X carries critical genes to survival
One of the X’s in a female turns off at a specific point in development of the
embryo; becomes a Barr body
***see notes again
-Color-Blindness: A sex-link trait is carried on the X chromosome
...

To be color-blind: Male must inherit color-blindness allele from his mother
...

For normal vision, male must inherit normal color-vision allele from his mother
...

-Duchenne- Muscular dystrophy- exclusively a male disease



Nondisjunction- the unequal distribution of chromosomes during meiosis (failure to
separate); the resulting gametes have zero or two copies of a chromosome, rather than
a single copy
...
) Genetic counseling: can look at likelihood
2
...

3
...
) Phenotypic Treatment after birth—need to have baby tested at birth
Friday, January 16, 2015



Human Blood Types
-3 alleles: A, B, and O
A and B are completely dominant to O, so AO=AA and BO=BB (phenotypically
equal)
OO= recessive; the only way to have a blood type “O” is to be OO

A and B are co=dominant, so “AB” is phenotypically equal to A + B (meaning AB
has both A and B carbs on RBC in the full amount)
The carbs on surface act as antigens (which is a substance that causes an immune
response)
...




Genome: an organism’s complete set of DNA; in eukaryotes, this info
...




Chromosome: one or more unique pieces of DNA- circular in prokaryotes, linear in
eukaryotes—that together make up an organism’s genome
...




Non-coding DNA possible functions:
-Functions in gene regulation
*upstream of genes there is a “regulator” sequence
-Many are gene duplications
...
512
1
...
) Transcribe/Elongation
3
...
) Cap and Process (Transcript needs a cap and a tail before it leaves the nucleus
...
14
-tRNA (t stands for transfer) = translator
-codes are in codons (3 letter “words”)

-AUG is “start codon”
-UAA, UAG, and UGA are “stop codons”
-redundant
-universal
-AUG→GCA→UUU
-AUG sets the “reading frame”
-tRNA is a nucleic acid that has an attachment point for a specific amino acid on one
end, and an “anti-codon” that is complementary to the corresponding codon on the
other end
-Transfer RNA (tRNA) molecules translate the mRNA code by linking specific bases
on the mRNA with specific amino acids that will be used to build a protein
...
) Recognize and initiate protein building/ Initiation
2
...
) Terminate
-The same mRNA molecule can be translated over and over again before it is
degraded, producing dozens or even hundreds of molecules of the proteins
...
will cause a frameshift

EVOLUTION
Wednesday, January 21, 2015


Why is evolution such a difficult topic? What makes it so controversial or
uncomfortable?



Why are Americans so much less likely to accept evolution than people in other
countries?
-Who advocates against it? Are they scientists?
Usually non-scientists advocate against it
-don’t know enough about it
-are misinformed
-avoided or toned down in public schools
-avoided in some parochial schools



How can someone be expected to have an opinion if are uninformed?
-belief in or acceptance of evolution increases with education:
High school or less: 21%
Some college: 41%
College graduate: 53%
Post-college: 74%
-this does not mean that people who do not believe in evolution are stupid; but
perhaps uninformed and do not understand evolution



Why is understanding evolution important?
-human welfare
-disease prevention
-crop production
-medicine
-our understanding of the natural world
**see article on rise of superbugs



Bio 110 goal: to give you tools to form your own, educated opinions

EVOLUTION


Define as: “The descent, with modification, of different lineages from common
ancestors… All forms of life… are related by unbroken chains of descent”;
continuous, ongoing



Major theme of biology



Unifies different aspects of biology



Widely accepted—is a scientific theory:
-broad statement supported by a large body of evidence
-generates many testable hypotheses
-must be falsifiable (capable of being proven true or false/ has to be testable)
-an explanation—of different facts/evidence



Science does not address supernatural; is not a moral, philosophical, or aesthetic code



Science cannot tell you what to believe but does give you facts to use to form and/or
challenge your beliefs
-creationism: life as explained in Genesis or other religious texts; “creation science”
but is not science; includes “intelligent design”



Unifying themes in biology
1
...
) DNA code/genetic code is universal
3
...
) All organisms are made up of: macromolecules (lipids, carbs, nucleic acids,
proteins)
5
...
) Mitosis and meiosis
7
...
) Explain both unity and diversity

RELATIONSHIPS BETWEEN EVOLUTION/SCIENCE AND
CREATIONISM/RELIGION


3 Models—Where are you?
1
...

-science view Earth very old (>>>>>6,000 years)

2
...
) Integration model: has regions of overlap, accepts both, no conflict


Points to ponder:
-does God/religion direct evolution?
-if God created all, how can we discover anything but what God created and
intended?
-Why would God give us brains if we are not to use them?
-evolution does not threaten God/religion
-accepting evolution does not diminish one’s relationship with God
-be cautious in interpreting scriptures



Charles Darwin (1809-1882; work was 1859): British naturalist…; studied medicine,
theology naturalist on Beagle (1831-1836): around the world venture
-More individuals of a given species are produced than can possibly survive
-individuals within a species are not all the same (lots of variation)
-those individuals best matched to environment will survive and produce more
offspring than those less well matched
-origins of new species and species’ adaptations to their environment are closely
related processes
-more successful traits will be more common in successive generations
-new species can arise from gradual accumulations of adaptations to different
environments
-Earth very old; continuous, gradual change
-natural selection/environment (as opposed to artificial selection) is mechanism of
change
-delayed publication: poor health (tropical diseases), anticipated uproar (knew what
he was publishing wasn’t going to be accepted well)



Alfred Wallace (1823-1913): developed theory of natural selection very similar to
Darwin’s (1858)



1859- Darwin published On the Origin of Species



By 1870’s, a lot of people accepted what Darwin was saying



Darwin’s Theory of Evolution by Natural Selection
What happens:
1
...
) Natural selection is mechanism by which adaptive evolution occurs over long
periods of time:
-organisms “over reproduce”, this leads to a “struggle for existence”
-who survives?
*those best fit are selected for/favored
*these survive and reproduce, passing on favorable characteristics to
offspring
*selection is controlled by environment/nature



Darwin didn’t propose mechanism for inheritance (did not know about genes)



Modern view: Evolution through natural selection:
1
...
) Only heritable traits may be amplified/diminished (acquired characteristics not
inherited)
3
...
) “Survival of fittest”: (ex
...
) Environmental change (or if individuals move to new environment) may favor/
cause selection for different characteristics (may→ new species)
6
...
) Individuals do not evolve; populations evolve (population: group of individuals of
the same species living in the same area)


How do populations evolve?
-gene: unit of heritable information in DNA
-alleles: different forms of a gene
-gene pool: all genes in a population at any point in time
-allele frequency: relative % of occurrence of allele in a population
*may change over time as environment changes, or as organisms move in or out
of area
*when allele frequency changes:
-gradual change in gene pool of a population
-favorable characteristics accumulate and less favorable ones disappear
-over time may → new species
P

PP Pp

10PP 10Pp

pp
10pp (60 alleles)

P 10 + 10 + 10= 30/60 = 50% P
p 10 + 10 + 10= 30/60= 50% p
later in time: 10 PP 8 Pp 2pp
frequency: P 10 + 10 + 8 = 28/40= 70%
frequency: p 8 + 2 + 2= 12/40 =30%
8
...
) Intentionally: plant and animal breeding
-pets, livestock
-horticultural, agricultural plants
2
...
) Genetic drift: random change in allele frequency
-founder effect: founding members of a new population have different
allele frequencies than the original source population
-bottleneck effect: occasionally, famine or disease or rapid environmental
change may cause the deaths of a large, random proportion of the individuals in a
population


How do we get new genes?
mutations: change in an organism’s DNA
-are the only source of completely new genes/alleles (raw material of evolution)
-rare: 1 per 100,000- 200,000 DNA replications
-can be in somatic or in sex cells (but can only affect gene pool if heritable)
-are random and unpredictable; but can be induced
-mostly bad (often lethal)
-some benign/neutral
-some good/advantageous to individual (rare unless there has been an environmental
change)
Ex: antibiotic/insect resistance to drug/pesticide:
Environment of microbe/insect changed
If random mutation results in organism better able to survive that
individual now favored by natural selection
Sexual reproduction also → variation:
Not by changing alleles but by allowing new combinations of existing alleles

Thursday, January 22, 2015
Microevolution

Macroevolution

Small scale

Large scale

Change in frequency of alleles within a

Change in population→ new species

population (within a species)

(“speciation”) and evolution of taxa
(taxon=group) above species

Generation to generation change

Occurs over millions of years; many
generations

Short time; observable more readily

Not readily seen; can be difficult to

accepted

accept

Examples: pesticide/antibiotic resistance

Evidence from: fossil record,
biogeography, comparative biology, and
molecular biology

EVIDENCE OF EVOLUTION (evolution is not a linear path)
1
...
4
...
3
...
) Biogeography- geographic distribution of species
-similarities among organisms on same continent
-species on islands most closely related to those on closest island or mainland
*Australian marsupials and their placental counterparts- pg
...
334
3
...
) Pelvic bones in snakes/whales
2
...
) Human appendix
4
...
4
...
4 bya



Endosymbiosis: intimate, permanent, ecological interaction where one species live
and reproduces inside the other to the benefit of one or both (mutualism)



Evidence of origin of eukaryotes by endosymbiosis: both mitochondria and
chloroplasts resemble prokaryotes
-reproduce same way (by splitting)
-reproduction is done independently of “host” reproduction
-have own enzymes
-have own ribosomes
-have own circular DNA

Friday, January 23, 2015
HUMAN EVOLUTION
Common misconceptions
Our ancestors were apes

Current scientific thinking/ evidence
Apes and humans evolved from a
common ancestor ca 4-7 mya

Apes →→→us
Proceeded by steps; each evolving into

Multiple pathways; different species co-

next

existed

Human characters evolved together

Different features evolved at different
rates/times



Ancestors probably lived in trees 30-35 mya



Did climate change lead to selection for bipedalism? (bi= two; ped= foot)

EVIDENCE FOR HUMAN EVOLUTION:


Paleoanthropology (the study of old humans): study of human organisms



Fossils



DNA and molecular analyses—can estimate time of divergence

CHARACTERISTICS OF ANIMALS:
1
...
) Move

3
...
431)
Descent with modification: organisms both
1
...
) Differ from ancestors/ new to group
Ancestral vs derived traits

Chordates
New characters:
1
...
Dorsal (in the back), hollow nerve cord → spinal cord and brain (CNS)
3
...
Muscular, post-anal tail
Vertebrates: chordates with backbones
Main new character: backbone:
-supportive structure that supports/ surrounds spinal cord
-simplest is cartilage; may have appendages
-most complex: bone completely surrounding spinal cord (vertebrae)
-some also developed swim bladders (to help keep a float) and lungs (air)
Life arose in water
 Transition to land (pg
...
) How to breathe (get O2) (respiration)
2
...
) Reproduction (egg desiccation)
Tetrapods (“four feet”): vertebrates with 4 limbs
Main new character: 4 limbs
-ancestors with fins →→→ muscle covered bones

-existence on land selected for additional bones
Amniotes: tetrapods producing amniotic egg (main new character)
-reptiles, birds, and mammals
-embryo has 4 membranes; innermost= amnion encloses embryo
-either have shell or develop within female parent (adaptation to life on land)
Mammals: amniotes that have hair and produce milk
-mammary glands
-hair/fur
-fat layer under skin (helps preserve body heat)
-larger brain/body size than other vertebrates
-parental care of young
-different types of teeth
-complex social behavior
COMMON ANCESTRY
 Humans did not evolve from modern apes
-Humans and modern apes shared a common ancestor (somewhere between 7 and 4
mya)
-Characteristics of the last common ancestor:
*Quadruped
*Palmigrade
*Arboreal climber/clamberer
-not a knuckle-walker, hanger, or vertical climber
*Generalized, omnivore teeth
PRIMATE CHARACTERISTICS
 Grasping hands and feet
 Flat nails (not claws)
 Ridges for griping on hands and feet (ours are fingerprints)
 Large brain
 Short jaws (reduced snout)
 Forward-facing eyes
 Mobile and opposable thumb

 Rotatable arms

TRENDS IN PRIMATE EVOLUTION
 Dexterous hands (able to manipulate small objects)
 Bipedalism
 Steroscopic vision → depth perception
 Large brain
 Infant care
 Broad flat teeth in a U-shaped jaw
TRENDS IN HOMININ EVOLUTION
 Bipedalism
-Physical adaptations: foramen magnum, hip joints
-Drier climate hypothesis
*More savanna → more walking
*Bipedalism conserves energy
-But, early bipedals did not live in the savanna (Ardi)
*Retained features of an arboreal clamberer
-Not the simple, abrupt evolution we might have thought
-About 2 mya, walking long-distance became “normal”
 Tool Use
-Modification of leaves and sticks is common among anthropoids (birds, too!)
-Complex tools (technology) may have happened about 2
...

 When we do, we look at:
-Geological matrix
-Associated flora and fauna
-Characteristics of the skeleton
**Male skull vs female skull (table 7
...

-Does physical evolution continue?



---