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Unit 1 – Classification of living things
species: members of interbreeding groups or populations that are reproductively isolated from other groups
and evolve independently
taxonomy: the branch of biology that identifies, names, and classifies species based on natural features
binomial nomenclature: the system of giving a two-word Latin name to each species
genus: a taxonomic group of closely related species
rank: a level in a classification scheme
taxon: a named group of organisms
DIFFERENCES BETWEEN PROKARYOTES AND EUKARYOTES
Prokaryote
Eukaryote
circular DNA, not bound by membrane, DNA in membrane-bound nucleus,
one chromosome
usually more than one chromosome
binary fission
mitosis & meiosis
asexual reproduction common
sexual reproduction common
unicellular
mostly multicellular
no membrane-bound organelles
membrane-bound organelles
most are anaerobic
most are aerobic
ANIMALIA
Porifera – giant sponge vase, redbeard sponge
Cnidaria – jellyfish, hydra
Platyhelminthes – flatworms, tapeworms, flukes, turbellarians
Nematode – roundworms, hookworms, pinworms, vinegar eels
Rotifera – rotifers
Annelids - earthworms, leeches, polychaetes
Mollusca - snails, clams, squids
Arthropoda – insects, crabs, mites, ticks, spiders, centipedes
Echinodermata – starfish, sea cucumbers, sea urchins
Chordata – fish, amphibians, reptiles, birds, mammals
ENDOSYMBIOSIS
- one cell engulfs a different type of cell
survives and becomes an internal part of the engulfing cell
- suggests that mitochondria and chloroplasts were once prokaryotes
- they were engulfed by other larger cells and remained intact
- continued to do inside the host cells what they had previously done
UNIT 2 – GENETICS
Chapter 4
CELL PARTS
nucleus – contains genetic information in chromosomes that directs all cell activities
nucleolus – transcribes & assembles ribosomal RNA (rRNA)
DNA - Deoxyribonucleic acid
- Individual units of each strand are nucleotides (composed of phosphate group, sugar group, & base)
- Sugar & phosphate form backbones of two strands, base pairs protrude inward at regular intervals
- Complimentary base pairs: A-T, G-C
- genome: the complete DNA sequence of an organism
- gene: a part of a chromosome that governs the expression of a trait (has a specific DNA sequence)
nuclear membrane – supports cell & allows some substances to enter while keeping others out
endoplasmic reticulum – transport materials (e.g. proteins) through cell
- rough ER: contains ribosomes that synthesize proteins
- smooth ER: involved in metabolism of carbohydrates and synthesis of lipids
ribosomes – synthesize proteins
Golgi apparatus – stores, modifies, and packages proteins from the rough ER
lysosome – contain enzymes which break down large molecules and cell parts
vesicle – store, transport, or digest cellular products and waste
vacuole – contains substances, removes unwanted substances from cell
central vacuole – storage, maintains turgor pressure
mitochondria – converts energy stored in glucose into usable form
chloroplast – contains chlorophyll, absorbs & converts light energy into glucose through photosynthesis
cell wall – provides support & protection
microtubule – transports materials through cytoplasm
microfilaments - thin filaments in cytoplasm, help provide shapes and movement for the cells
chromatin: strands of uncondensed DNA in nucleus
chromatid: one of two condensed strands of DNA that make up a duplicated chromosome
chromosome: a pair of chromatids held together by a centromere
centrioles: forms spindle fibres
centromere: a structure which holds chromatids together as chromosomes
spindle fibre: a microtubule structure that facilitates the movement of chromosomes
homologous chromosomes: paired chromosomes similar in shape, size, gene arrangement
MITOSIS
Prophase:
- nuclear membrane breaks down
- chromatin condenses into chromosomes
- centrioles migrate to opposite poles
Metaphase:
- centrioles have reached opposite poles
- spindle fibres are sent out by centrioles and attach to centromeres
- chromosomes line up in middle
Anaphase
- spindle fibres retract & pull on the chromatids
- chromatids are pulled apart
- chromatids become sister chromosomes upon separation
Telophase
- sets of chromosomes have reached opposite poles & unwind into chromatin
- nuclear membrane reforms around each set of chromosomes
- cytokinesis (splitting of cell and cytoplasm) is initiated
DIFFERENCE BETWEEN PLANT & ANIMAL CELLS IN CELL DIVISION
Animal cells – during cytokinesis, pinches off in the center
Plant cells – plate forms between the daughter cells and develops into a new cell wall
MEIOSIS I
Prophase I
- nuclear membrane breaks down, chromatin condenses into chromosomes, centrioles migrate to
opposite poles
- homologous chromosomes line up side by side  synapsis
- crossing over may occur
Metaphase I
- centrioles have reached opposite poles
- homologous pairs line up at center
- spindle fibres attach to centromeres (one chromosome per side)
Anaphase I
- spindle fibres retract
- intact chromosomes are pulled to opposite poles
- one chromosome from each pair moves to a given side
Telophase I
- chromosomes uncoil
- nuclear membrane forms around each group of chromosomes
- cytokinesis  two haploid cells form
MEIOSIS II
Identical to meiosis, but haploid
karyotype chart: a photograph of pairs of homologous chromosomes in a cell
- cell sample is collected and treated to stop cell division during metaphase
- sample is stained to produce a banding pattern on the chromosomes
- chromosomes are sorted and paired, arranged in order of length
- autosomes are numbered 1 to 22 and sex chromosomes are labeled X or Y
gamete: a male/female reproductive cell
zygote: a cell formed by the fusion of two gametes
fertilization: in humans, the joining of male and female gametes
haploid: a cell that contains half the number of chromosomes as the parent cell
diploid: a cell that contains pairs of homologous chromosomes
synapsis: the aligning of homologous chromosomes during prophase I in meiosis I
spermatogenesis: the process of producing male gametes (sperm)
- takes place in testes
- process starts with a spematogonium (diploid), which reproduces by mitosis
- resulting cells undergo meiosis to form four haploid cells
- following meiosis II, cells undergo a final set of developmental stages to develop into sperm
(nucleus and certain molecules are organized into a head region, middle section hold many
mitochondria, and a flagellum develops for locomotion)
oogenesis: the process of producing female games (eggs)
- takes place in ovaries
- starts with an oogonium (diploid), which, before birth, reproduces by mitosis and begin meiosis but
stop at prophase I
- Meiosis I will continue for one cell each month beginning at puberty
- Involves unequal division of cytoplasm
- Cell that receives most cytoplasm after first division continues through meiosis
- Other, smaller cell is a polar body, which will degenerate
- Final stages of meiosis II are not completed unless fertilization occurs
- When meiosis II is completed, mature egg and another polar body are produced
independent assortment: there are various ways that chromosomes may be aligned in metaphase I of
meiosis – the orientation of each pair of chromosomes is independent of the orientation of other pairs 
different combinations of chromosomes found in the gametes
- # of variations = 2n
crossing over: the exchange of chromosomal segments between a pair of homologous chromosomes
ERRORS IN MEIOSIS
mutation: a change in the genetic material of an organism  only source of new genetic material
- Deletion: a part is cut out accidentally
- Duplication: extra copies of a section are made
- Inversion: a section is chopped out, rotated 180 degrees and rejoined
- Translocation: a section moves to a new location
non-disjunction: the failure of homologous chromosome pairs/sister chromatids to separate during meiosis
(one entire pair/sister chromatids are pulled to the same pole in anaphase I and II)
 can lead to gametes missing or having an extra chromosome – monosomy or trisomy upon fertilization
DISORDERS
Down Syndrome (Trisomy 21)
- Intellectual disabilities
- Thick facial features
- Short stature
Turner’s Syndrome (XO)
- Individual is female, but lower level of female hormones released to the system
 secondary characteristics will be underdeveloped (breasts, hips  cannot have children)
Jacob’s Syndrome (XYY)
- higher levels of testosterone/androgens
- taller tendencies
Klinefelter’s Syndrome (XXY)
- Genetically and physically male, but body will not produce as much testosterone
 underdeveloped secondary sexual characteristics (higher voice, less muscle, less body hair, unable
to produce functioning sperm)
“Superfemale” (XXX or more)
- Tall, thin, menstrual irregularity
Chapters 5 & 6
allele: a single variant of a gene
dominant: the form of a trait that always appears when an individual has an allele for it
recessive: the form of a trait that only appears when an individual has two alleles for it
law of segregation: traits are determined by pairs of alleles that segregate during meiosis so that each
gamete receives one allele
genotype: the combination of alleles in a given organism
phenotype: the physical expression of the genotype
homozygous: an organism with two identical alleles of a gene
heterozygous: an organism with two different alleles of a gene
Punnett square: a grid used to illustrate all possible genotypes and phenotypes of offspring from genetic
crosses
monohybrid cross: a cross of two individuals that differ by one trait
dihybrid cross: a cross of two individuals that differ in two traits due to two different genes
law of independent assortment: during gamete formation, the two alleles for one gene segregate
independently of the alleles for other genes
chromosome theory of inheritance: traits determined by genes are inherited through the movement of
chromosomes during meiosis
autosomal dominant: the inheritance of a dominant phenotype whose gene is on an autosomal chromosome
autosomal recessive: the inheritance of a recessive phenotype whose gene is on an autosomal chromosome
incomplete dominance: a condition in which neither allele for a gene completely conceals the presence of
the other  results in intermediate expression of a trait
codominance: the condition in which both alleles for a trait are equally expressed – both are dominant
sex-linked trait: a trait controlled by genes on the X or the Y chromosome
-
if disorder is X-linked dominant, affected males pass the allele only to daughters, all of which have
the disorder; females can pass an X-linked dominant allele to both sons and daughters
if X-linked recessive (e.g. CVD, hemophilia), male only needs to inherit one allele to be affected,
while the female must inherit both
Unit 3 – Evolution
Earlier Europe was dominated by the Catholic Church, which insisted that the world was created 6000 years
ago and has not changed (geological & biological change does not occur). Life was created in a single
moment, and did not chance since then.
1700s:
1. Carl von Linné
- created a classification scheme
*categorized apes with humans  controversy
2. George-Louis Leclerc, Comte de Buffon
- wrote Histoire Naturelle
- said the Earth is older than 6000 years
- insisted that natural phenomena must be explained through natural laws, not theology
3. Erasmus Darwin
- said that life must have been evolving for millions of years before the commencement of mankind
 In the world, fossils were being discovered & interpreted as mythical creatures
4. George Cuvier
- proposed catastrophism:
o organisms in one area are killed of simultaneously by a catastrophe
o the area recovers, sediments settle over dead, organisms from surrounding areas move in
 explained the differences in fossil layers
 showed that changes geologically occur
5. Charles Lyell:
- proposed uniformitarianism:
o changes in the world occur gradually but are ongoing
o the world has always undergone change
o we can understand changes in the past by studying changes in the world today (occur at the
same rate)
6. Jean-Baptiste de Monet, Chevalier de la Marck
- proposed inheritance of acquired traits:
o In the life of an individual, needs can drive change. The individual will adapt to the
environment, and the changes they make will be passed on to offspring.
 e.g. short necked giraffe stretch to reach tall trees, traits are passed to offspring (who
will have stretched neck)
- spontaneous generation:
o simple organisms formed spontaneously and then evolved to become a modern organism,
with population splitting to form different related species
Charles Darwin’s Theory of Evolution
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-
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variation exists within every population
o some visible (e.g. hair color, joint positions, vision), some not (e.g. fovea depth, number of
red blood cells produced, metabolism)
# of offspring produced > # that will survive to reproduce given limited resources (e.g. water, food,
shelter, sunlight, temperature, mate, etc.)  creates competition to survive
competition leads to selection as to who will survive & reproduce –
survival of the fittest = survival of those best able to compete for & exploit the resources
o natural selection: environment exerts selective pressure on population, created competition
for limited resources and causing some organisms to be out-competed and die
o sexual selection: choice/competition for mate – male/female makes the selection for mate
o artificial selection: choice of who mates made by humans
Speciation (formation of new species)
METHODS OF REPRODUCTIVE ISOLATION
Prezygotic (prevent mating):
1. Geographical isolation – geography separates individuals from potential to mate
e.g. lion (in Africa) and tiger (in Asia)
2. Ecological isolation – individuals separated based on ecology
e.g. species of beetle are genetically compatible, but one species mate only one a particular flower
type, while the other will mate only on a different flower type
3. Behavioral isolation – individuals differ based on mating call/dance/ritual
e.g. in cities, low-pitch noises blend into background noise and can be lose, while countryside is quit
and low pitch noises can be heard  city birds develop high-pitched mating call, country birds
remain low pitched  don’t recognize each others’ songs  don’t mate
4. Temporal isolation – separated based on mating season/timing for releasing pollen/flowering
e.g. one species flowers in early May, another in late June  pollen from one cannot fertilize other
Preventation of Fertilization:
5. Mechanical isolation – anatomical differences
e.g. praying mantis: female kills mate during mate just before deposit of sperm, other species would
not be able to pass on sperm that quickly
6. Gametic isolation – eggs and sperm are not compatible, don’t have correct chemical markers
e.g. fish release millions of egg and sperm in water everyday; markers on egg must be compatible
with markers on sperm of same species
7. Zygotic mortality – egg can be fertilized, but offspring will not survive to birth
e.g. sheet + goat  offspring dies before birth
8. Hybrid Inviability – offspring can survive to birth, but dies shortly afterwards, before reproductive age
9. Hybrid infertility – offspring lives full life, but cannot form viable eggs/sperm  cannot reproduce
e.g. donkey + horse  mule/hinny, which cannot produce own offspring
TYPES OF SELECTION
Stabilizing – average in population is favored
e.g. birth weight – too high/too low decreases chance of survival
Directional – one extreme is favored; occurs when new pressure exists in the environment, new selective
force is introduced, causing shift in average
e.g. in breeding Dachshund from regular dog, shorter were favored over tall, leading to shift in
average height until the ideal height was reached
Disruptive – 2 extremes are favored  leads to split and increase in diversity of a population; 2 new species
can be derived from one
e.g. one species of fish has two types of male: big aggressive fish and small sneaky fish were most
successful as surviving
EVIDENCE FROM FOSSILS
fossil record: remains of past life that are found in sedimentary rock – reveals history of life on earth and the
kinds of organisms that were alive in the past
1. fossils found in younger (top) layers of rock are much more similar to species alive today than fossils
found at older (deeper) layers
2. fossils appear in chronological order in the rock layers  probable ancestors for species found in older
rocks, which lie beneath later species
3. not all organisms appear in the fossil record at the same time  suggests that amphibians evolved from
ancestral fish, reptiles from ancestral amphibians, and mammals & birds from reptiles
transitional fossils: fossils that show intermediary links between groups of organisms and shares
characteristics common to each of the now separate groups (e.g. fossils that link modern whales to ancestors)
EVIDENCE FROM ANATOMY
Homologous structures: features that have the same origin but serve different functions
e.g. structure of arms & hands - # and organization of bones are same in human arm, horse leg, bat
wing, and whale fin  suggests common origin
Analogous structures: features that have different origins, but a common function
e.g. wings of bees, bats, and birds
Vestigial structure: any feature that does not have a function in one species but does in other organisms
 suggests its function has degenerated (not selected for and thus is wearing away genetically)
e.g. whales have hip bones – degenerated in size, but has same shape
humans have appendix (which in herbivores, houses bacteria which break down cellulose)
EVIDENCE FROM EMBRYOLOGY
- embryos of different organisms exhibit similar stages of embryonic (e.g. vertebrate embryos have
paired pouches of the throat; in fish & amphibians, develop into gills; in humans, pouches become
parts of ears and throat)
-
yolk sac in human development – provides nutrients to developing embryos of birds and reptiles, but
does not support human embryo development
EVIDENCE FROM DNA
- many genes are common in related species (e.g. growth hormone – shape and effect is identical in
mice, pigs, humans, etc.; testosterone – horse steroids have same effect on humans as horses)
FACTORS WHICH CHANGE ALLELE FREQUENCIES
1. Mutation – introduces new alleles
2. Gene flow (migration) – movement of genes between populations as a result of migration of individuals
3. Genetic drift – random shift in populations from generation to generation due to chance/random events
Bottleneck effect: changes in a gene pool result from rapid decrease in population (dumb luck
allows some to survive, others die  survivors only have some of the alleles that were present before)
Founder effect: chance in gene pool that occurs when a few individuals start a new isolated
population  founders will carry some but not all of the alleles from the original population
4. Natural selection
5. Non-random mating
adaptation: a structure, behavior, physical characteristic, or physiological process that helps an organism
survive and reproduce in a particular environment
mimicry: an adaptation in which a species resembles another, providing them with a survival advantage
selective advantage: a genetic advantage that improves an organism’s chance of survival, usually in a
changing environment
selective pressure: conditions that select for certain characteristics of individuals and select against others
fitness: the relative contribution an individual makes to the next generation by producing offspring that will
survive long enough to reproduce
descent with modification: Darwin’s theory that natural selection does not demonstrate progress, but merely
results from a species’ ability to survive local conditions at a specific time
sympatric speciation: speciation in which populations within the same geographical area diverge and
become reproductively isolated
allopatric speciation: speciation from geographical isolation of populations
gradualism: changes in species occur slowly and steadily over time
punctuated equilibrium: populations remain unchanged over a period of time, but sudden changes in
environment occur, leading to rapid changes and new species forming
divergent evolution: a pattern of evolution in which species that were once similar to an ancestral species
diverge or become increasingly distinct
convergent evolution: a pattern of evolution in which similar traits arise because different species have
independently adapted to similar environmental conditions
UNIT 4 – INTERNAL SYSTEMS
Chapter 10
macromolecule: a very large molecule made up of smaller molecules that are linked together
Carbohydrates
- provide energy storage for organisms
- always contain carbon, hydrogen, and oxygen
- monosaccharides: a simple sugar with 3 to 7 carbon atoms (e.g. glucose, fructose)
- disaccharides: a sugar made up of two monosaccharide molecules (e.g. sucrose, maltose)
- polysaccharides: a large molecule made up of many linked monosaccharide molecules (e.g.
glycogen, amylose, cellulose)
Proteins
- help build & repair muscles and cell membranes
- assembled from amino acids (building blocks of protein)
- most proteins are made of amino acids joined by peptide bonds
- these chains are called polypeptides
- most enzymes and antibodies are proteins
Lipids
- insoluble in water
- store energy
- e.g. fats , oils
ENZYMES
- protein molecule that help speed up important chemical reactions in the body
- secreted by digestive tract
- act as catalysts – increase rate of chemical reactions without being used up in the reactions
- e.g. carbohydrase, lipase, protease, nuclease
COMPONENTS OF DIGESTIVE SYSTEM
Mouth:
 Salivary glands secrete salivary amylase and water (saliva)
1. breaks down amylose (starch) into shorter/simpler chain sugars
2. makes food moist and malleable
 Tongue, teeth, and hard palate work together too mash and mix the food into a bolus
Pharynx, Uvula, Epiglottis:
 When food makes contact with the back of the throat, it has entered the pharynx
 A swallow reflex is triggered  tongue & throat move in conjunction to move the food down
into the esophagus


Uvula – flap which blocks off the nasal cavity during swallowing
Epiglottis redirects food into the esophagus, away from lungs
Esophagus:
 Tube connecting the pharynx to the stomach
 When the bolus enters the esophagus, it triggers a peristaltic contraction, a chain reaction
muscle contraction in esophagus that drives the bolus into the stomach
Stomach:
 When food is anticipated, or enters the stomach, cells lining the stomach release HCl acid which
activates a protein called pepsinogen, making it into pepsin, an active enzyme which breaks
down peptide bonds between amino acids in proteins, into polypeptides
 Acid also kills most microorganisms which may be present in the bolus
 Stomach mashes & mixes the food
Small intestine:
 When food enters the small intestine, the pancreas releases fluids into the intestine:
1. base: bicarbonate ions – neutralizes acid
2. enzymes:
a) pancreatic amylase & maltose to break down disaccharides (in carbs)
b) trypsinogen  trypsin; c) erepsin (break down proteins)
long chain peptides – tripsin  short chain peptides – eripsin  amino acids
d) lipase (breaks down fats/oils)
 Gallbladder secretes bile salts which emulsify (breaks large droplets into small droplets) fats &
oils  makes it easier for lipase to break down the fats
Large intestine:
 Compacts the waste left over
 Reabsorbs water and some nutrients
 Rectum & anus regulate the outflow of waste
DIGESTIVE SYSTEM DISORDERS
Peptic ulcer – a sore in the lining of the stomach or duodenum, where hydrochloric acid and pepsin are
present
- form when tissues become inflamed because the protective mucus that covers the lining has
weakened
- most commonly caused by infection with Helicobacter pylori
- symptoms: abdominal pain, bloating, nausea, loss of appetite
- treatment: antibiotics that kill the bacteria, and other medications that reduce acidity
RESPIRATORY SYSTEM
Inspiration:
- muscles and the diaphragm contract, and the diaphragm moves down
- this expands the ribcage, and since the chest cavity is airtight, its volume increases
-
the molecules of gas become farther apart and exert less outward pressure
the air pressure in the chest cavity decreases and the lungs expand
the expansion causes the air pressure in the lungs to be lower than the air pressure outside the body
air moves from higher pressure to regions of lower pressure  air rushes into the lungs
Expiration:
- diaphragm and muscles relax, reducing the volume of the chest cavity
- volume of lungs decreases, air pressure inside the lungs increases  air moves from the lungs to the
lower pressure environment outside the body
COMPONENTS
pharynx: passageway behind mouth that connects mouth and nasal cavity to larynx and esophagus
trachea: tube that carries air from nasal passages/mouth to bronchi
glottis: the opening to the trachea through which air enters the larynx
larynx: the structure between the glottis and trachea that contains the vocal chords
bronchus: the passageway that branches from the trachea to the lungs
bronchiole: the passageway that branches from each bronchus to increasingly smaller, thin walled tubes
alveolus: a tiny sac with thin walls found at the end of a bronchiole
RESPIRATORY SYSTEM DISORDERS
Laryngitis: inflammation of larynx
- caused by infection or allergy, or by overstraining the voice (e.g. prolonged yelling)
- when inflamed, the vocal cords that the larynx contain cannot vibrate as they usually do
- people with laryngitis may lose their voice or speak in a hoarse whisper
- usually not serious, clears up in a few days
CIRCULATORY SYSTEM
Functions
1. transports gases, nutrients, and wastes
2. regulates internal temperature and transports vital chemical substances
3. protects against blood loss from injury and disease causing microbes or toxic substances
COMPONENTS OF THE CIRCULATORY SYSTEM
heart: muscular organ that pumps blood to lungs and body
blood vessel: a hollow tube that carries blood to and from body tissues
DISORDERS
arteriosclerosis: walls of arteries thicken and lose elasticity, become harder
atherosclerosis: plaque builds up inside artery walls  artery narrows, blood flow is decreased and blood
pressure increased
heart attack: blood clot to heart prevents enough oxygen from getting to heart
stroke: interruption of blood supply to brain