Bio 2 lab

In what eon did life first appear?

Arcaheon eon

When did eukaryotes first appear in the fossil record?

1.8 billion

In what era and periods were the dinosaurs most prevalent?

Mesozoic era cretaceous period

What period did the dinosaurs go extinct?

Cretaceous period

What era and period did the first mammals appear?

Mesozoic era triassic period

What is the significance of the Cambrian explosion? When did it occur?

535 million years ago, first abundant life found in the rock record

When did land plants appear in the fossil record?

470 million years ago

What is mass extinction?

 Events where large number of groups of organisms die off

Know the major events (i.e. The different mass extinctions) for the transition between different time periods

late Ordovician (ordovican-silurian) 445 mya

late devonian (Devonian-Carboniferous) 360 mya

Permian triassic 252 mya (great dying)

Triassic Jurassic 201 mya

Cretaceous- Paleogene 66 mya

What era and period did the first hominins appear? 

Cenozoic era and the Neogene period

How many mass extinctions have occurred? 

5

What are some of the possible causes of the Permian and Cretaceous mass extinctions?

volcanoes for the permian and asteroid for the cretaceous

Which mass extinction was the largest? What is the percentage of life that went extinct in this extinction?

Permean where 96% went extinct

Describe relative dating?How is it used to date fossils?

relative dating is when you say a object is older or younger compared to something else instead of giving exact or absolute number

fossils are compared to surrounding rock layers and other fossils,

What is superposition? Can this method work all the time in dating fossils?

says that oldest layers are at the bottom and the youngest at the top, this doesnt work all the time because layers werent deposited horizontally or they have been overturned

How is absolute dating performed?

using the decay of radioactive isotopes

1/ln(2)/half life ln (1 + d/p)

What are the conditions that need to be met for populations to be in Hardy-Weinberg Equilibrium?

population must be large, mating is random, no natural selection, no mutation, no gene flow (migration)

What does it mean for a population to be in genetic equilibrium?

frequency of alleles in population remains the same

What does it mean for there not to be any selection occurring? 

one trait doesn’t give a advantage over another

What does each factor in the H-W equation represent? i.e. What does q², 2pq, p² p or q represent?

p - dominant allele frequency
q- recessive allele frequency

p² - homozygous dominant genotype frequency
q² - homozygous recessive genotype frequency
2pq - heterozygous genotype frequency

If there is selection, what happens to allelic frequency and genotypic frequency? (think about your “fish experiment”)

the allele and genotypes that are more advantageous become more frequent

What is genetic drift?

random change in alleles within a population (small)
bottleneck effect - random effect natural disaster, less allele variation
founder effect - new colony is formed with only small number of people, less allele variation

What does it mean for an allele to become “fixed”? 

everyone is homozygous for that allele, 100%

What does it mean for an allele to become extinct?

allele has disappeared from population

What types of populations does genetic drift have its biggest impact?

small populations

What does Hominin refer to? 

modern humans ( homo sapiens) and all their bipedal ancestorss

What does Hominid refer to? 

great apes and their ancestors

What osteological characteristics help Paleoanthropologists decide if a fossil will be classified as a hominin fossil or a non-human primate?

foramen magnum towards the front indicated bipedalism, prognathism or protruding snout are found in older, humans have larger brain size smaller mouth and teeth, no sagittal crest, smaller zygomatic bone

Be able to identify a skull and determine what specimen it is.  i.e. gorilla, chimpanzee or hominin 

Be able to use information from the lab to determine which came first bipedalism or big brains?

bipedalism came first, foramen magnum moved to the front of skulls which indicates bipedalism before increase of cranial size

What aspects of the skeleton are indications of that specimen being bipedal? 

foramen magnum toward the front, s shaped spine, bowl shaped pelvis, female angled inwards, arched foot with heelbone

What aspects of a skeleton are clues for a specimen being a quadruped? 

foramen magnum in back, limbs and legs are similar in length, c shaped spine

You should be able to measure the different points used to measure cranial capacity, euryon to euryon point (eu to eu), Ba to b height and Glabella to opisthocranion (g-op).

L x B x H /3 = cranial capacity

L - front, back
B - width
H- top bottom

What does the size of the zygomatic arch and the presence or absence of a sagittal crest tell you about the diet of different hominin species? 

if present it indicates that they had tough hard plant foods

What does it mean if there is a large zygomatic arch and or a sagittal crest on a skull? 

large and powerful jaw muscles

What is sexual dimorphism? 

male and female of same species have different physical features

You should be able to ID male versus female pelvis characteristics. 

female have wider pelvis for childbirth, wider sciatic notch and pubic arch and pelvic inlet

You should be able to identify the different parts of the pelvis if labeled. 

Be able to identify male versus female gorilla skulls and the secondary sexual characteristics of the male

male have bigger teeth , secondary characteristics - muscle development, large sagittal crest, silver gray hair on back ( silver back)

What is a dichotomous key? 

checklist tool that’s used to identify organisms based on their observable traits

What characteristics are used to develop a dichotomous key, how is it constructed? 

morphological traits and physical characteristics, it would be a series of contrasting statements that narrow the options down until final id

What are the different levels of the taxonomic system? Should be able to place them in order of breadth. (i.e. which is the most broad category? which is the most narrow?)

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

How are organisms named in the taxonomic system?

genus and species, binomial nomenclature, genus capitalized both italicized

What are the 4 kingdoms of Eukarya? 

Protista, Fungi, Plantae, and Animalia

What types of organisms are in each domain (i.e. what are the defining cell types of each domain?)

Three domain, Bacteria and archaea (prokaryotes), Eukarya ( eukaryotes)

Describe the differences between prokaryotic organisms and eukaryotic organisms. 

eukaryotes have nucleus, membrane bound organelles, reproduce sexually, can be single or multicellular
prokaryotes- single celled, reproduce asexually, have circular DNA that floats freely

How do you use a micropipette?

Select the correct pipette, attach a new tip, set the volume, press to the first stop before entering the liquid, slowly release to draw liquid, then dispense using the second stop

Determine which micropipette to use for a given volume

P10: 0.5–10 µL, P20: 2–20 µL, P200: 20–200 µL, P1000: 100–1000 µL

What are phylogenetic trees? How are they constructed? In terms of scientific inquiry, what are phylogenetic trees considered?

a branching diagram that illustrates the evolutionary relationships among biological species or entities. They are constructed by analyzing shared physical characteristics or genetic data to identify shared ancestry, then organizing species into nested groups based on these homologies, considered hypothesis of evolutionary history

What types of data are used to construct phylogenetic trees? 

most common - dna sequence, sometimes fossil record or morphological data

What are sister taxa? 

two distinct species/ groups that share an immediate common ancestor, closest relative

What is a basal taxon? 

species that diverges early in the group

What is a polytomy? 

more than two descendant species from single node

what is a clade?

branch on the phylogenetic tree

How are molecular sequences analyzed to compare different species? 

aligning the genetic code of different species to identify similarities and differences

How are insertions and deletions that occur accounted for? 

inserting empty spaces represented by gaps -

what is muscle alignment?

software that aligns your unknown DNA alongside reference sequences of known species

What are the approximate lengths of a DNA barcode?

650-800

What gene is used to barcode for fish, vertebrates, and invertebrates? 

COX1 or COI gene. mitochondrial cytochrom c oxidase subunit 1

What gene is used to barcode plants? 

matK (maturase K) rbcL (rubisco)

What is used to barcode fungi and lichen? 

ITS internal transcribed spacer

What is an exon and an intron? 

exon is coding segment , intron is non coding

What are the introns used for in barcoding? 

classify organism at the species level

What is the coding (exons) region of a gene used for in Barcoding? 

develop primers for the barcode aiding in amplification via PCR

Be able to formulate the correct in-text citation using APA style rules. 

Smith & Jones, 2025 1-2 authors
Smith et al., 2025 3 authors

How do you use a micropipette? What are the rules for using micropipette tips?

adjust the dial to the desired volume, press the plunger to the first stop, immerse the tip, and release slowly to aspirate. To dispense, press past the first stop to the second stop
utilizing a fresh tip for each unique sample

What is PCR? 

polymerase chain reaction, repeating cycle of heating and cooling to make billions of copies of DNA

Know the different stages of PCR and what occurs in each stage. 

Denaturing - 95c
annealing - 50 to 65 c
extension - 72c

How are genes identified in Gel electrophoreses? 

DNA is negatively charged and moves toward the positive electrode

How is DNA visualized on a gel? 

using dyes like sybr safe and then viewed under UV

Be able to determine the size of DNA fragments based on their location on a gel. 

Smaller fragments travel faster and further than larger ones

What is Sanger sequencing and what does it tell you? 

a method for determining the exact order of nucleotide bases, tells you the exact letter sequence,

How is a DNA sequence analyzed to identify species? 

sample is collected, amplified. sequenced and then compared against database

How are DNA fragments compared between species? 

the number of mismatches is used ,

What is a Phred Score? 

measure that allows you to determine the confidence level for each nucleotide

What does the Phred score tell you about sequence data? How is it used to determine the quality of sequence? 

it tells you the quality of the sequene data, if the bars are above the blue lines its a good quality higher than 99%, very few N between beginning and end

Determine if fetal pig is male or female

male has scrotum and urogenital orifice right under umbilical cord, in female its right near the tail

Be able to identify the testicles, the ovaries,

the urogenital papillae, the urogenital opening of the pigs.

Be able to identify the ventricles and atriums of the heart. 

Be able to identify the lungs and diaphragm of the pig. 

Be able to describe which part of the heart receives oxygenated and deoxygenated blood. 

right side receives deoxygenated and left side receives oxygenated

You need to know the direction of the flow of blood to and from the heart. 

blood returns to the heart thorough the inferior and superior vena cavae to the right atrium to the tricuspid valve into the right ventricle which pumps through the pulmonary artery to lungs, comes back through the pulmonary vein oxygenated to the left atrium through the bicuspid valve into the left ventricle which contracts pushing the blood through the aortic valve and aorta throughout the body

What do the coronary arteries do? 

supply heart with blood

What vessels carry blood to the heart from the body? 

veins

What vessels carry blood away from the heart?

arteries

Do all veins carry deoxygenated blood? 

no pulmonary veins cary oxygenated blood from lungs to left atrium

Do all arteries carry oxygenated blood? 

no pulmonary artery carries deoxygenated blood from heart to lungs

Be able to identify the intestinal tract, the stomach, small and large intestines, the liver, kidneys, spleen etc. 

What do the liver and kidneys do for the body? 

the liver processes nutrients and neutralizes toxins, the kidneys filter out waste and excess fluids to be excreted as urine

What are sensory papilla on the tongue used for? What are the different tastants and how are they detected? 

they are used for taste, sweet, sour, bitter, umami, salty

eukaryote has nucleus

Be able to Identify a sample as either a bacteria or a protist. 

Be able to determine if a sample is a prokaryote or eukaryote.

Coccus - spheres
rods - bacilli
spirillum - spiral
vibrio - comma curved rod

What are the different bacteria shapes we saw in lab? 

What does the classification of Gram-positive or Gram-negative mean?

Gram positive have thick cell wall while gram negative has thin wall in between two  lipid by layers

Be able to recognize a bacterial specimen as gram-positive or gram-negative by its color. 

Gram positive - purple, gram negative - red / pink

Which bacterial types are more susceptible to antibiotics?

Gram positive

What are the cell wall structural differences between gram positive and gram negative bacteria?

gram positive has thick peptidoglycan layer on outside, gram negative has thin layer in between two lipid bi layers

What is the zone of inhibition? what does the measurement tell you about a specific chemical or antibiotic? 

clear area around where bacteria stopped multiplying, tells you the effectiveness of antimicrobial agent

What are cyanobacteria? 

bacteria capable of oxygenic photosynthesis also called blue green algae

Be able to identify the cyanobacteria specimens we looked at on the microscope in lab.