BIO 180 Quiz 1

What are some advantages of the bar chart over the histogram?

• bar charts allow for easier comparison

• cleaner

• standard deviation (how close the data is)

  • test 80% if the standard error is +/2 then the average test scores is from 78%-82%

What are some advantages of the histogram over the bar chart?

• see + understand data better

• showing more data when graphing is always improtant

What is a null hypothes?

• There is no statistical difference between the groups being studied

What does cannot reject the null hypothesis mean?

What does can reject the null hypothesis mean?

• There is no statistical difference between the data of the groups being studied

• There is enough statistical difference between the data of the groups being studied

p-value

• Likelihood of obtaining your results

• p-value < 0.05: the data is significant (a smaller # means there is a smaller chance of confounds)

  • Reject the null

What do overlapping standard error bars mean?

• overlapping: cannot reject the null

• non-overlapping: can reject the null

Standard Error calculations

• p = sample proportion (percent)

  • ex: .36 = 36"%

• n = number of individuals being tested

How does sample size effect standard error?

• as sample size goes up, standard error always goes down

Graphing tips:

• Show as much data as possible (histograms)

  • If a bar graph is used, add points

  • Simplify when appropriate; provide enough information for the general audience to understand

  • Dependent variable: y-axis

  • Independent variable: x-axis

Darwin’s Theory of Natural Selection (4 Postulates)

1. Variation: individuals in a population are variable

2. Inheritance: some of this variation are passed on to offspring

3. excess reproduction: not all individuals produce the same number of offspring

4. Differential success: individuals with certain heritable traits produce the most offspring

Natural selection occurs when 1. leads to 2.

1. heritable variation

2. differential reproductive success

the outcome of this process is evolution: a change in frequencies across generations

Blending inheritance vs Mendelian inheritance

• Blending inheritance: crossing a black bunny with a white bunny results in a grey bunny

• Mendelian inheritance: certain biological traits are passed down from parents to offspring through a single gene

  • Proves genes are particulate: genes act like individual, independent particles passed completely intact

How did Gregor Medal discover that blending inheritance wasn’t correct?

• After crossing a tall pea plant with a dwarf pea plant, the entire generation was tall pea plants

  • 50% HH 50% Hh

• After crossing the F2 generation, 75% of the offspring were tall, and 25% of the offspring were short

  • AA, Aa, Aa, aa

• The reappearance of the dwarf pea gene was evidence that genes were particulate and were passed as independent particles

Homozygote, heterozygote

• Describe the combination of alleles an organism inherits from its parents

  • Homozygous: same XX

  • Heterozygous: Xx

Explain: Each individual has two copies of each gene?

• Every offspring gets one variant of a gene from the mother and one from the father

  • BB

  • Bb

  • bb

    • One allele from either parent: B vs b

What is a quantitative trait?

• Traits that don’t fall into discrete categories but are measured on a continuum (continuous variation)

  • Skin color, height, IQ + cognitive ability

phenotype and genotype

• Genotype: the genes

  • TT

• Phenotype: physical appearance

  • TT: tall

What does a haploid number mean?

What does ploidy mean?

• The number of different types of chromosomes

  • diploid (2), triploid (3)

• The number of copies of chromosomes

1.blank n = 2.blank

1 = ploidy

n = haploid

2 = total number of chromosomes

Mitosis

• a process of cell division where a single cell divides to form two genetically identical daughter cells

Prophase, Metaphase, Anaphase, Telophase (Mitosis)

• DNA packs tightly together into visible chromosomes

• The chromosomes line up perfectly down the middle of the cell

• The matching chromosome pairs are pulled apart and move towards opposite sides of the cell

• Two new nuclei form around the separated sets of DNA

Which of the following has properly labelled DNA?

3

• The chromosomes are identical, and the alleles on both sides of the chromatid are the same

  • sister chromatids must be identical

Draw: Original cell is 2n=4 with genotype AaBb

• 2 identical diploid cells

Meiosis

• a type of cell division that reduces the chromosome number by half to create four genetically unique haploid cells

Prophase I, Metaphase I, Anaphase I, Telophase I (Meiosis I)

• Prophase I: the most crucial step for genetic diversity

  • Crossing over: homologous chromosome pairs find each other and trade random chunks of DNA

  • This shuffles the alleles so that a single chromatid might end up with a mix of maternal and paternal traits

• Metaphase I: the chromosomes line up down the center of the cell in pairs

  • Random assortment: the chromosomes randomly line up down the middle of the cell

• Anaphase I: the pairs are pulled apart. The blue chromosome goes to one side, and the red chromosome goes to the other

  • segregation (separation): the parent cell separates its two copies of a gene so that each sperm or egg receives one allele

• Telophase & Cytokinesis I: the cell splits; you now have two haploid cells, but the chromosomes inside them are still duplicated X shapes

Prophase II, Metaphase II, Anaphase II, Telophase II (Meiosis II)

• Meiosis II is similar to meiosis I, except there is no DNA replication

• Metaphase II: The individual X chromosomes line up down the middle of the cell

• Anaphase II: the identical sister chromatids are finally pulled apart

  • segregation (separation): the parent cell separates its two copies of a gene so that each sperm or egg receives one allele

• Telophase & Cytokinesis: both cells split right down the middle

What is non-disjunction?

• Nondisjunction is when the chromosomes fail to separate correctly during anaphase

  • Instead of pulling apart neatly so that each gets an equal share, chromosomes get stuck together

  • down syndrome

Genetic variation is a result of?

• independent assortment and crossing over

autosomal (unlinked):

• Genes located on non-sex chromosomes (autosomes) that either reside on different chromosomes or are far apart on the same chromosome

  • allowing them to segregate independently

  • AaBbEe

Linked chromosomes:

• Different genes that are physically located close to each other on the same chromosome

  • They are inherited together

  • Ae//eE Bb or Ae//aE Bb

    • The slash represents linked genes

Sex-linked chromosomes:

• The specific chromosomes that determine the biological sex of an organism and carry genes that dictate sex-specific traits as well as non-sex traits

  • X^Eg X^eGAa Bb

  • X^Eg Y Aa Bb

Assuming NO crossing over, this fly can create which of the following gametes? BD//bd kk X^RY

1. B D k X^R (not showing they are linked)

2. B d k Y (not showing they are linked)

3. Bd/ k X^R/Y (X^R/Y gametes done get both)

4. Bd/ k Y (Bd never linked)

5. bd/ k X^R (correct)

Describe

• State relative features, characteristics, or changes

• Stick to what the evidence SHOWS, not why it’s happening

  • The data shows that

  • as X increases, Y decreases

Explain

• Connect a biological mechanism or cause to an outcome

• Why or how does it happen?

  • This occurs because

Compare/Relate

• Discuss both things using the same feature or criterion

• If the question asks how two processes differ, merely describing one is not enough

• MUST DESCRIBE BOTH

Identify a pattern

• What relationship appears in the data

  • How do the variables change together

  • There is a positive relationship between X and Y

  • The groups differ in… with… showing …

Define

• give the precise meaning of a term

• X is…

State

• Give a direct fact or answer, usually brief

  • X is..

Identify

• name the relevant structure, process, variable or result

Predict

• state a expected result, often using a biological principle

Justify

• support a claim with evidence and reasoning

Interpret

• explain what data or a result means biologically

Evaluate

• asses strengths, weaknesses, or how well evidence supports a claim

  • One strength… but a limitation is

Answering questions about patterns and data

1. Name the variables

2. Describe the trend

   1. Does the measured variable increase, decrease, or remain stable

3. Include a meaningful comparison

4. Explain the biology only if asked