BSC 111L: Practical on Topics 1, 2, 3, 4, 6

Hypothesis

Hypothesis

a proposal intended to explain certain facts or observations

theory

a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena

Bacteria Archaea Eukarya

Domains of Life

Species Genus Family Order Class Kingdom Domain

Taxonomic levels (most inclusive to least inclusive)

binomial nomenclature

the scientific name of an organism

capitalized

in binomial nomenclature, the first letter of the genus of a species is

lowercased

in binomial nomenclature, the species epithet is

italicized/underlined

in binomial nomenclature, the entire scientific name is

sister taxa

share an immediate common ancestors(each other's closest relative)

most recent common ancestor

found at each branch point, represents most recent ancestor shared by all descendants

node

ancestors on a phylogenetic tree

taxon

any level of taxonomy, any named group of organisms

clade

a group of organism which includes the most recent common ancestor and all the descendants of that most recent common ancestor: a monophyletic group

outgroup(basal taxon)

any taxon used to help resolve polarity of characters, hypothesized to be less closely related to each of the taxa than any are to each other

node

where they diverge, representing a speciation event from a common ancestor.

Branches

represent lineage

phylogenetic tree

diagram that represents evolutionary relationships between organisms

descent with modification

another name for natural selection, coined by Charles Darwin

evolution

CHANGE in the composition of the population OVER TIME (generation to generation)

Natural selection

a mechanism of evolutionary change, the driving force of evolution. a genetically based variation that leads to evolutionary change

reproduction

mechanism of natural selection species reproduce in excess of the numbers that can survive

genetic variation

mechanism of natural selection, all sexually reproducing species vary in characteristics

heredity

mechanism of natural selection, the biological process whereby genetic factors are transmitted from one generation to the next

fitness

Those individuals with hereditary characteristics that have survival value; improved fitness are more likely to survive and reproduce compared to less fit individuals. Successful reproduction

natural selection

the more fit individuals, the more reproduction, and thus traits change in a population

independent variable

the variable you change in the experiment

dependent variable

the change that happens because of the independent variable

control variable

the constant of an experiment, onw e variable should be different than the test group

qualitative data

physical appearance ex: color, odor

quantative

measurements ex. meters, weight

replicates

repeating the experiment for more data

steps of the scientific method

-Question(observation) -Hypothesis(answer to question) -Test/Experiments -Collect Data -Analyze Data -Conclusion

Comparative analogy

Evidence of Evolution homologues structure between individuals. ex: hair in all mammals, bones in whale flippers and bones in the human arm

Homologous structures

characteristics that are similar due to INHERITANCE from shared evolutionary ancestors. used to group organism in biological categories such as mammals or fish

Analogous structures(analogies)

similar characteristics that evolve independently as adaptions to similar environments and functions. ex: evolution of wings in bats, bird and insects Not directly related

DNA Comparison

Evidence of Evolution compares sequences of nucleotides in organism DNA. Similar sequences Indicates that they had a recent shared evolutionary ancestor. ex: hippo milk casein is 83.4% similar to whale casein (refer to packet)

Comparative Embryology

The early stages of development can contain some characteristics of evolutionary ancestors that are absent in adults. Often, later stages of development MODIFY characteristics ex: human embryos contain tails in early development(mammalian characteristic)

Fossil Record

fossils that are preserved can be compared to life on earth today. They show that life on earth was once different from life found on earth today. Studies genetic and morphological divergence

-ex: whale tail flukes evolved from a complete loss of back legs from genetically similar fossils

Microevolution

changes in allele frequency of a population over time

observation of microevolution

different phenotypical colors of a mouse or another organism is a

Domain Bacteria

-prokaryotic -unicellular -contain peptidoglycan in the cell wall -membrane lipids: contain UNBRNACHED hydrocarbons -aerobic or anaerobic

-peppered moth -antibiotic resistance -glucose tolerant insects

Observation of microevolution

Domain Archaea

ancient bacteria EXTREME ENVIRONMENTS Anaerobic (do not need oxygen) Do not contain peptidoglycan(contain pseudopeptidoglycan) -Membrane lipids: contain some branched hydrocarbons ex: thermophiles, halophiles

Prokaryotes

no nucleus, no organelles contain domain bacteria and archaea

1%

percent of bacteria that are pathogenic

bacillus

rod shaped

mutualistic symbolic association

the presence of 500- 1,000 species of bacteria in our digestive system/ skin benefits us and the bacteria is an example of

cocus

circle shaped

spirillum

spiral shaped

strep

bacteria form in chains

staph

bacteria in clusters

gram +

represents peptidoglycan in cell wall stains purple

gram -

represents bacteria with less peptidoglycan in the cell walls plus an additional membrane

Gram staining process

1: crystal violet (primary stain) 2. Iodine (mordant) 3. Alcohol (decolorizer) 4. Safranin (counterstain)

Oil Immersion Technique

1. Focus normally on the slide up to 40X objective

2. Move the revolving nose piece until it is halfway between 40X and 100X objectives

3. Place ONE drop of oil onto the center of the slide

4. Rotate to the 100X objective and use ONLY the Fine Focus knob The objective lens MUST be touching the oil

5. When you are done viewing your slide, carefully turn back to a lower power lens and remove the oil from the slide and the lens with cleaning flu

Bacterial wet mount slide

-transfer of the bacteria to a slide using a sterile inoculation loop (metal loops are sterilized in flame) • using a flame to kill the bacteria and stick them to the slide (called “heat fixing”) • addition of a stain like methylene blue (though there are other options)

methane blue

Common Staining agent

Ocular Lens (10x)

eyepiece

4x

Scanning lens maginifcation

10x

Low power magnifcation

40x

high power magnifcation

tot magnification = (magnification of ocular lens) X (magnification of objective lens)

How do to find the total magnification

Iris diaphragm

adjustable shutter which allows you to adjust the amount of light passing through the condenser.

nose piece

revolving turret

objective lens

can have a magnifying power ranging from 4x to 100x. 4 – 5 lenses are used on microscopes depending on the required magnifying power.

coarse focus knob

knob which moves the microscope stage a larger distance per rotation

Fine focus knob

the smaller of the smaller of the two knobs and is located further away from the arm of the microscope.

stage

The specimen that is to be viewed is placed on the here

Protist

any eukaryote which are not plants, animals, or fungi

protozoa

protists which are capable of movement and are HETEROTROPHS

Algae

protists that are autotrophs (using photosynthesis)

protists do not form a monophyletic group based on DNA

protists are not a kingdom because

eukaryotic

organism that contain a nucleus and organelle

phagocytosis

protozoa ingest food by the uptake of large particles or whole organisms by pinching inward of the plasma membrane

mixotrophic

protists capable of photosynthesis and ingestion

Trypanosoma gambiense

single-celled heterotrophs locomotion: flagellated

Trychonympha

protists that are common in the intestines of almost all termites locomotion: flagellum nutrition: heterotrophs-> capable of cellulose digestion

Amoeba Proteus

locomotion: pseudopodia nutrition: hetertrophic, pseudopodia used to take a cell by phagocytosis free living organism

pseudopodia

cells move by extending their organs om sequence and flowing into the first one and then the amoeba proceeds in a irregular fashion

Blepharisma

free-living protist common in fresh and salt water Nutrition: cilia, heterotrophic movement: cilia

Globigerina

also called foraminifera locomotion: thread like pseudopodia nutrition: pseudopodia, heterotrophs

diatoms

algae single celled cell wall made of silica locomotion: hair like the lateral flagellum nutrition: photoautotrophic major component of phytoplankton

dinoflagellate

algae locomotion: flagellum nutrition: photoautotrophic can cause algal blooms "red tides"

Euglena

algae (green algae) nutrition: mixotrophic organism -> photosynthesizes using chloroplasts but switches to heterotrophy when sunlight isn't available locomotion: flaglleum