AP Biology Review

1
AP Biology Review

• Part 2

2
Reproductive BarriersLeading to Speciation

• Prezygotic Barriers
• Postzygotic Barriers

• Habitat Isolation
• Temporal Isolation
• Behavioral Isolation
• Mating
• Mechanical Isolation
• Gametic Isolation
• Fertilization
• Reduced Hybrid viability
• Reduced Hybrid fertility
• Hybrid breakdown

3
Lab 8Population Genetics and Evolution

• You used the class as a sample group to look at
  the relationship between violating a
  Hardy-Weinberg condition and the changes in
  allele frequency.
• Evolution here is defined as change in allelic
  frequency.
• Hardy and Weinberg independently suggested a way
  to view evolution as changes in frequency of
  alleles in a population.
• If certain conditions are met the allele and
  genotype frequencies will remain constant from
  generation to generation. They are
• Hardy-Weinberg Conditions
• Large Population
• Random Mating
• No Mutation
• No immigration or emigration
• No selection

4
Hardy Weinbergp2 2pq q2 1

• Total of all alleles p q 1
• p A allele, q a allele
• p2 AA homozygote (dominant)
• pq Aa heterozygote
• q2 aa homozygote ( recessive)

5
4 of a sheep population has black wool, 96
white. If black wool is recessive what of the
population is heterozygous?

• q2.04
• q v.04 .2
• 1-q p
• 1-.2 .8
• So q .2 p.8
• Substitute in 2pq
• 2 (.8) (.2) .32 or 32

6
4 of a sheep population has black wool, 96
white. If black wool is recessive what of the
population is heterozygous?

• What of the population is homozygous for white
  wool?
• Substitute in for p2
• .82 .64 64

7
A Few Genetics Terms

• Autosomal traits- on non-sex chromosomes.
• Sex-linked-genes on sex chromosome
• sex-influenced- trait that appears differently in
  different sexes. On autosomes.
• Sex-limited- characteristic appearing exclusively
  in one sex but whose gene is usually on an
  autosome.
• Allele- form a trait can take.
• Test cross-cross between an unknown genotype with
  a pure recessive for the trait (you always know
  the genotype from the phenotype).
• Linked genes- on same chromosome. Wont show
  classic mendelian ratio.
• Crossing over- exchange between homologous
  chromosomes.

8
A Few more genetics terms

• Interaction between alleles
• 1. Complete dominance- one allele appears
  phenotypically if present.
• 2. Incomplete dominance- The phenotype is
  intermediate between the dominant and recessive
  form, often due to ½ the product of the gene
  being produced.
• 3. Codominance- both alleles are fully expressed.
• 4. Multiple alleles- more than two alleles for a
  gene are found within the population (not within
  an individual).
• 5. Epistasis- one gene alters the effect on
  another gene.
• 6. Polygenic inheritance- many genes contribute
  to a phenotype.
• 7. Pleiotrophy- one gene can effect several
  phenotypic traits.
• 8. Environmental Influence- where the genotype
  and environment interact to determine the final
  phenotype.

9
Lab 7 Genetics of drosophila

• You collected data from a fruit fly cross and
  analyzed results,
• Drosophila have 4 pairs of chromosomes.
• They show complete metamorphosis-egg, larvae,
  pupa, adults.
• We looked at three types of crosses
• monohybrid-single contrasting pair of
  characteristics.
• Dihybrids-two pairs of contrasting traits are
  considered simultaneously.
• Sex-linked-mutant characteristic associated with
  the X chromosome. (white eyes).
• Pgeneration-pure parents
• F1 offspring of the P generation
• F2 offspring of the F1 generation

10
Lab 7 Genetics of drosophila-analysis

• You counted e.g. 67 red eyed flies
• 33 sepia flies
• You would expect 31 ratio
• 100 x ¾ 75 (100 is the total number of flies)
• 100 x ¼ 25
• Chi- square- statistic used to see if your
  results are close enough to the expected results
  to be acceptable (significant)
• X2 ? (o-e)2 o observed
• e e expected

11
Lab 7 Genetics of drosophila-analysis

• X2 (67-75)2 (33-25)2 3.41
• 75 25
• Determine degrees of freedom
• Categories 1 So 2-1 1

If probability from the Chi-Square table is
greater than your value you may accept your null
hypothesis- There is no statistically
significant difference between your observed and
expected data.
12
Genetics question

• A male fruit fly with red eyes and long wings was
  mated with a female with purple eyes and
  vestigial wings. All of the offspring in the
  F1generation had red eyes and long wings.
• These F1 flies were test crossed with purple-
  eyed vestigial winged flies. Their offspring,
  the F2 generation, appeared as indicated below
• 125 red eyed, long winged
• 124 purple eyed, vestigial winged
• 18 purple eyed, long winged
• 16 red eyed, vestigial winged

13
Genetics question

• Knowns Purple and vestigial are recessive- The
  F1 generation in a dihybrid cross shows the
  dominant trait because all of the organisms are
  hybrid. This was a special cross, it was a test
  cross in the F1 generation.
• P cross was ppvv x ppvv
• F1 generation was ppvv (all red long)
• F1 test cross was ppvv x ppvv
• p purple v vestigial
• P wild red v wild long

14
Genetics question

• F2

pv pv pv pv
pv ppvv ppvv ppvv ppvv
Red, Long Red, Vestig. Purple Long PurpleVestig.
This cross does not show a typical 9331 ratio
of a dihybrid cross. Nor does it show the
1111 ratio predicted from the Punnett Square
(see above). The number of parental types seen
in the F2 is large and indicates there is linkage
of the two traits. They are on the same
chromosome. Crossing over is responsible for the
few recombinants.
15
Lab 4Plant Pigment and Photosynthesis

• Part I You separated plant pigments using
  chromatography.
• Part II You measured the rate of photosynthesis
  is isolated chloroplasts.
• We used a blue dye, DPIP. When it is reduced
  (OIL RIG) it goes from blue to clear.
• Electrons usually reduce NADP but reduce reduce
  DPIP instead in this setup.
• You measured transmittance of light using the
  cholorimeter.
• You compared rate of
• Unboiled in the dark (no light to excite the
  electrons)
• Unboiled in the light
• Boiled in the light ( chloroplast membranes were
  disrupted)
• No Chloroplasts (Control)

16
Plants

• Meristems-generate cells throughout the plants
  life.
• Apical- extend roots and shoots (Primary Growth)
• Lateral- add girth (secondary growth)
• Transport tissues
• Xylem-water and minerals
• Phloem- carry sugar
• Xylem is made of
• Tracheids- long thin
• Vessel elements- wider, shorter
• Both are dead at functional maturity
• Movement of water from roots to leaves occurs by
• Bulk-Flow- the movement of fluid driven by a
  pressure difference at opposite ends of a
  conduit.
• The pressure difference is generated at the leaf
  end by transpirational pull ( lower pressure) at
  the leaf end.
• Water pulled tight against the cell walls in the
  air spaces of the leaf cause the negative
  pressure which draws water up xylem.

17
PlantsAlternation of Generations
Sporophyte
Meiosis
Zygote
Sporophyte Generation (2n)
Gametophyte Generation (n)
Spore
? ?
Fertilization
Gametes
Gametophyte
18
Major Branches of the Animal Kingdom
Protostomes Mollusks, Annelids and
Arthropods -Spiral Cleavage (cell divisions are
along a diagonal line) -Determinate (cell fate is
established early) Mouth forms from
blastopore Schizocoelus (solid masses of mesoderm
form coelom)
Coelomate Have a true coelom- a body cavity lined
with tissue of mesodermal origin
Bilateria (bilateral symmetry) Cephalization 3
germ layers
Porifera Sponges

• Deuterostomes
• Echinoderms and Chordates
• -Radial Cleavage (cell divisions line up with the
  original cell divisions).
• Indeterminate (allows for identical twins!)
• anus forms from blastophore
• Enterocoelous (outpockets of the archenteron form
  the coelom)

Animals
Pseudocoelomatea Rotifer-Coelom not completely
lined by mesoderm
Subkingdom Eumetazoa
Radiata-Cnidarians Radial Symmetry
Acoelomate No cavity between the gut and the body
wall. Flatworm Platyhelminthes
19
Germ Layers and Their Derivatives

• There are three germ layers
• Ectoderm
• Endoderm
• Mesoderm

20
Germ Layers and Their Derivatives

• Ectoderm
• Epidermis and associated parts hair and nails
• Lens and retina of the eye
• Enamel of teeth
• Nerve Cells
• Medulla of the adrenal gland
• Inner Ear

21
Germ Layers and Their Derivatives

• Endoderm
• Inner lining of
• Alimentary Canal
• Lungs
• Middle ear and eustachian tube
• Gallbladder
• Lung tubes
• Urethra
• Urinary Bladder
• Bulk of
• Thyroid
• Parathyroids
• Thymus (where immune cells mature)
• Pancreas
• Liver
• Prostate Gland

22
Germ Layers and Their Derivatives

• Mesoderm
• Dermis of skin
• Connective tissue
• Cartilage
• Bone
• Lymphoid Tissue
• Blood
• Blood Vessels
• Heart
• Skeletal Muscles
• Smooth Muscles
• Kidneys
• Testes
• Ovary
• Cortex of the Adrenal Gland

A partial list for all germ layers.
23
Operons

• In Prokaryotes
• Region of a chromosome where a set of genes are
  transcribed at one time.
• Allows all of the enzymes needed for a pathway to
  be present at once.
• Two Types
• Inducible are usually off but can be turned on.
  Like the lac operon.
• Repressible are usually on but can be turned off.
  Like the trp operon.

24
Muscle Contraction

• Sliding Filament Theory of Contraction
• Thick (myosin) and thin (actin) myofilaments
  slide past one another shortening the muscle.
• Control- Ca from the sarcoplasmic reticulum
  floods the muscle fiber when depolarized by a
  nervous impulse. The Ca moves the regulatory
  protein (tropomyosin) out of the way, by binding
  to troponin, allowing the cross bridges to form.
• Functional unit Sarcomere
• Muscle fibers can be slow-twitch (slow to
  fatigue) or fast twitch ( quick source of power)
• Cardiac muscle-interconnected
• Smooth muscle-lack myofilament organization, but
  still use sliding filament theory.

25
Circulatory System

• Open or closed (kept in vessels, all
  vertebrates).
• No separate blood and lymph in the open system
  (like insects). Fluid is not called blood. It is
  hemolymph.
• Blood vessels carry blood
• Plasma-carries ions, proteins, hormones and
  metabolites.
• Formed elements of the blood are erythrocytes
  (red blood cells)-carry O2
• Leukocytes (white blood cells)-fight infection.
• Platelets-cell fragment function in blood
  clotting.
• Blood Vessels
• Arteries carry blood away from the heart, Veins
  to,
• Lymphatic System returns interstitial fluid to
  the bloodstream. Moves through lymph nodes where
  many cells of the immune system search for
  antigens

26
Evolution of the Heart

• Fish-
• Single loop- to the gills, body, gills
• Two chambered heart
• Amphibians and reptiles
• Double loop
• Three chambered heart
• Mammals and birds
• Double loop
• Four chambered heart
• Better for active animals-keep oxygenated and
  deoxygenated blood separate,

27
Lab 11aAnimal Behavior

• You looked at the response of organisms to
  environmental variables.
• Ethology is animal behavior
• Behavior may be
• Learned
• Innate (inherited)
• Orientation Behaviors- help animal find the most
  favored environment.
• Taxis-toward or away from a stimulus
• Kinesis- random movement-not orienting toward a
  stimulus.
• Agonistic behavior
• Animal response that is aggressive or submissive.
  
• Mating behavior
• Complex behaviors that promote continuing the
  species.

28
Lab 11BReproductive Behavior in Fruit Flies

• Mating follows a distinct behavioral pattern, a
  courtship pattern.
• 1. Orientation
• 2. Male Song (wing vibration)
• 3. Licking of the female genitalia
• 4. Attempted copulation
• 5. Copulation
• 6. Rejection (extrusion of ovipositor)

29
Blood Clotting

• Vessel damaged, muscle cause constriction.
• Platelets adhere, form a plug
• Platelets pinch off from large cells in the bone
  marrow called megakaryocytes
• Enzymatic reactions below are triggered by the
  platelets adhering.
• Prothrombin is converted to thrombin
• Fibrinogen is converted to fibrin which
  reinforces the clot the platelets are forming.