PowerPoint Presentation
Course: BIOL 117 General Biology 2 Lab Instructor: Anne Rybicki,
PhDEmail: [email protected] or contact me through Blackboard
Course description: This course examines the mechanisms of
evolution through the exploration of the five kingdoms of life,
both on the basis of their unique anatomical structures and
adaptations as well as those conserved through evolutionRequired
Texts:Explorations in General Biology Laboratory, Eileen Walsh,
2011 (ISBN 978-0-7575-8927-0)I will post the Powerpoint intro to
each lab on Blackboard after class each week Attendance: Attendance
is required and will be taken at every lab period; students must
arrive on time and stay for the entire lab period; there will be no
makeup lab quizzes; exams can only be made-up if you have a valid
excuse and you notify the instructor before the exam. Please read
the assigned lab investigation before coming to labGrading: Your
grade in the lab will comprise 25% of your course grade. It is a
departmental policy that a student must receive a minimum grade of
50 to receive credit for the courseThe lab grade will be determined
byLab work (taxonomic key): 10% (I will also check your lab
books)Tests (3 tests): 90% (tests will be both written and
practical)Students at Westchester Community College must abide by
the Honor Code. Anyone caught cheating on an exam will receive a
grade of 0 for that exam. Additionally, the Chairman and Provost
will be informed in writing and the student will receive an F for
the courseStudent obligations:No eating/drinking in the lab and
please set your cell phones to silent mode. You must leave your
work area the same as you found it (clean; all equipment put away)
Lab 1 (1/23): Exercise 14 Classification and survey of the
kingdoms: prokaryote; protista; and fungiLab 2 (1/30): Exercise 15
Bryophyta; Exercise 16 PterophytaLab 3 (2/6): Exercise 17
Coniferophyta; Exercise 18 AnthophytaLab 4 (2/13): Test 1Lab 5
(2/20): Exercise 19 Anatomy of the flowering plantLab 6 (2/27):
Exercise 19 Anatomy of the flowering plantLab 7 (3/6): Test 2Lab 8
(3/13): Exercise 20 Porifera; Exercise 21 CnidariaSpring break
3/17-3/23Lab 9 (3/27): Exercise 22 Annelids; Exercise 23
MolluscsLab 10 (4/3): Exercise 24 Arthropods; Exercise 25
EchinodermsLab 11 (4/10): Test 3Lab 12 (4/17): Exercise 26 Fetal
pigLab 13 (4/24): Exercise 26 Fetal pigLab 14 (5/1): Exercise 31
Use and construction of a taxonomic key dueLab 15 (5/8): Test 4
(given the week before Finals week)
Taxonomy is that branch of biology dealing with the
identification and naming of organisms
Five kingdoms based on their cell structure and sources of
nutrition:
1-Monera: includes Eubacteria and Archaebacteria; heterotrophic
and autotrophic prokaryotes
2-Protista: heterotrophic and autotrophic eukaryotes
3-Fungi: heterotrophic
4-Plantae: autotrophic
5-Animalia: heterotrophicAutotrophs- organisms that are able to
make energy-containing organic molecules from inorganic raw
material by using basic energy sources such as sunlight (plant
kingdom) Heterotrophs- organism that obtains organic food molecules
by eating other organisms (animal kingdom)
Carolus Linneus, a Swedish botanist, developed the concept of
binomial nomenclature, whereby scientists speaking and writing
different languages could organize biological organisms; when
writing genus and species information, the Genus is always
capitalized, the species lower-case, and both are italicized e.g.
Homo sapiensLinnean hierarchical classification was based on the
premise that the species was the smallest unit, and that each
species nested within a higher categorySpecies- organisms that can
interbreed and produce viable, fertile offspring
Human Taxonomy
Kingdom AnimaliaPhylum (Division for plants) Chordata Class
Mammalia Order Primates Family Hominidae Genus Homo species
sapiens
Earliest organismsDomain Bacteria Domain Archaea Found in
extreme habitats; live without oxygenKingdom Protists
Kingdom MoneraKingdomPlantaeDomain
EukaryoteKingdomFungiKingdomAnimaliaThe Structure and Function of
ProkaryotesProkaryotic cellsLack true nuclei; the nucleoid is a
region where the circular chromosome (DNA) is locatedPlasmids are
accessory rings of DNALack other membrane-enclosed organelles;
ribosomes are the only cytoplasmic organelles. They are smaller
than eukaryote ribosomesHave cell walls exterior to their plasma
membranes; the cell wall prevents bursting or shrinking when the
osmotic concentration changesThe cell is surrounded by a capsule
(attached) and/or by a loose gelatinous sheath (slime layer). This
layer helps attach the cell to attach to environmental surfaces.
Many prokaryotes adhere to surfaces by short hair-like structures
called pili or fimbriae.Some move by means of flagella; the
flagellum contains a hook and a basal body. It rotates 360 degrees
to propel the cell.
Plasma membrane(encloses cytoplasm)Cell wall
(providesRigidity)Capsule (stickycoating)Prokaryoticflagellum(for
propulsion)Ribosomes(synthesizeproteins)Nucleoid(contains DNA)Pili
(attachment structures)Prokaryotes
SHAPES OF PROKARYOTIC CELLSSpherical (cocci)Rod-shaped
(bacilli)SpiralLab exercise-observe slideEubacteria- characterized
according to their shape, motility (presence of a trichus), and
composition of their cell wallsProkaryotes come in several
shapes:Spherical (cocci)Rod-shaped (bacilli)Spiral
Streptococci (filamentous)
Staphlococci (divide along multiple axes)
A Gram stain of mixed Staphlococcus aureus (Gram positive cocci)
and Escherichia coli (Gram negative bacilli); Gram-positive: Thick
peptidoglycan wall becomes dehydrated and retains the crystal
violet purple stainGram-negative: Need a pink counterstain
(safanin) because the crystal violet stain is not retained
(lipopolysaccharides in outer wall dissolve with alcohol)
Gram-positive bacteria have cell walls that are made up of 50-90%
peptidoglycan. When crystal violet stain is used to stain the
bacteria and the decolorizer (alcohol) is added, the thick cell
wall becomes dehydrated and traps the crystal violet inside the
bacteria; gram-positive bacteria stain purpleGram-negative bacteria
generally possess a thin layer of peptidoglycan between two
membranes. After the bacteria are stained with crystal violet, the
decolorizer (alcohol) removes the outer cell membrane and the
crystal violet is also lost; gram-negative bacteria stain pink with
the safanin counterstain
Cyanobacteria: blue-green in color, which is why they are often
called blue-green bacteria. They are common in ponds, lakes,
streams and moist areas of land. They are composed of chains of
bacteria (filamentous) and contain phycocyanin, a bluish pigment
that absorbs light, and chlorophyll, a pigment involved in
photosynthesis, a process that uses the suns energy to make sugar
molecules. Cyanobacteria are photosynthetic prokaryotes
Oscillatoria is a genus of filamentous cyanobacterium which is
named for the oscillation in its movement. Filaments in the
colonies can slide back and forth against each other until the
whole mass is reoriented to its light source
Anabena- a genus of filamentous cyanobacteria that exists as
plankton. It found in colonies and is known for its nitrogen fixing
abilities. During times of low environmental nitrogen, about one
cell out of every ten will differentiate into a heterocyst (lacking
pigmentation). Heterocysts then supply neighboring cells with fixed
nitrogen in return for the products of photosynthesis (sugars),
that they can no longer perform. This separation of functions is
essential because the nitrogen fixing enzyme in heterocysts,
nitrogenase, is unstable in the presence of oxygen. heterocystLab
exercise-observe slideKingdom: ProtistsProtists are not one
distinct group but instead represent all the eukaryotes that are
not plants, animals, or fungi.Protists differ from prokaryotes
because they are eukaryotes that have a nucleus and contain DNA in
chromosomesProtists are divided into three groups based on physical
characteristics (locomotion) and modes of nutrition: protozoa
(animal-like protists); heterotrophs (ingest food particles) algae
(plant-like protists; includes seaweeds); photoautotrophs (make
food through photosynthesis) slime molds (fungal-like protists);
chemoheterotrophs (absorb organic molecules)Animal-like protists
have 3 different modes of locomotion: flagella, cilia, and
pseudopods; includes Paramecium, Euglena, and AmoebaMost species of
Euglena have photosynthesizing chloroplasts within the body of the
cell, which enable them to feed by autotrophy, like plants.
However, they can also take nourishment heterotrophically, like
animals. They are considered mixotrophs, an organism that can use a
mix of different sources of energy and carbonLab exercise-observe
slide
Euglena gracilis
Lab exercise-observe slide
Amoeba proteusFood beingingestedPseudopodiumof amoebaLab
exercise-observe slidePlant-like protists contain plastids which
are very similar to chloroplasts; may be that a cyanobacteria
became an organelle in a protist cell by endosymbiosis
Plant-like protists include diatoms and SpirogyraUnicellular
algae are diatoms in the Phylum Bacillariophyta. Some have shells
composed of silica. Most are photosynthetic and are an important
part of the aquatic ecosystem known as plankton. They produce much
of the oxygen we breathe, and also take in much of the carbon
dioxide from the atmosphere
The siliceous shells of diatoms have many uses, such as in
reflective paint, in toothpaste, or as a filter (diatomaceous
earth)
Lab exercise-observe slideSpirogyra is a genus of filamentous
green algae named for the helical or spiral arrangement of the
chloroplasts. It also has a large central vacuole
Lab exercise-observe slideMost protists are unicellular and can
live independently or in colonies (filamentous organisms). Some
protists are truly multicellular where the cells within the
organism are specialized for different purposes. Brown algae (kelp;
Laminaria) in the Phylum Phaeophyta is multicellular with different
body structures e.g. the holdfast that attaches the kelp to an
immovable surface
Fungal-like protistsPhylum Myxomycota contains plasmodial slime
molds such as Physarum. They reproduce sexually and contain haploid
and diploid forms during their life cycle. The diploid feeding
stage of the organism is known as a plasmodium due to a process
called syngamy (when cells fuse); the plasmodium is therefore
multinucleated. Under dry conditions (or when food is scarce),
stalked reproductive structures called sporangia form. Haploid
spores are formed by meiosis. Under wet conditions, the haploid
spores germinate and fuse before fertilization.
Feeding stagedrywetLab exercise-observe slide
When it is wet, the spores germinate; when it is dry, the stalks
form and spores are produced
Animal-like protistAnimal-like protistAnimal-like
protistPlant-like protistFungal-like protist
A model for the evolution of multicellular organisms from
unicellular protists.UnicellularprotistColonyEarly multicellular
organismwith specialized, interdependent
cellsLocomotorcellsFood-synthesizingcellsLater organism withgametes
and somatic cellsSomaticcellsGameteMulticellular eukaryotes include
fungi, plants, and animals
Fungi are multicellular eukaryotes
Multicellularity is a big step in evolution because organisms
with many cells can then use different cells for specific
functions; they can also grow larger
Kingdom Fungi Decomposers- break down organic material and
recycle vital nutrients; saprotrophic- decompose dead matter Fungi
are heterotrophs and absorb nutrients from outside their bodies
They use enzymes to breakdown complex molecules into simpler ones
Body structures: multicellular fungi and single cells (yeasts) The
morphology of multicellular fungi enhances their ability to absorb
nutrients They are composed of mycelia, networks of branched hyphae
adapted for absorption Most fungi have cell wall made of chitin
(plant cell walls have cellulose and pectin; bacterial cell walls
have proteoglycan)
3 phyla: zygomycetes, ascomycetes, basidiomycetes based on type
of reproductive structures
1-Phylum Zygomycetes Zygosporangia (sexually produced
reproductive structures), which are resistant to freezing and
drying, can survive unfavorable conditions Black bread mold
Rhizopus nigricans Hyphae absorb nutrients During sexual
reproduction, the haploid gametes from + and strains fuse (zygote)
and then form a thick zygospore in which meiosis occurs forming
haploid spores Upon germination, a sporangium is formed and haploid
spores released
Lab exercise-observe petri dish
HyphaeMyceliaSporangiaSpores
Life cycle of RhizopusZygosporangium resistant to harsh
conditionsFusion of hyphaeSexual reproductionFusion of nucleiSexual
reproduction-fusion of hyphae (plasmogamy); fusion of nuclei
(karyogamy); production of spores in zygosporangia (meiosis)
Asexual reproduction- germination of haploid spores by mitosis
to form mycelia
2-Phylum Ascomycetes Called sac fungi Sexually, produce haploid
spores in sacs called asci Asexually, produce spores called conidia
in projections of hyphae called conidiophores Sac fungi also
include unicellular yeasts (Saccaromyces or bakers yeast) and the
multicellular morels, truffles, and Penicillium
conidia
Budding yeast: Saccharomyces cerevisiae (Ascomycetes)
Lab exercise-observe slideDifference between conidia and
ascospores.Conidia tips of specialized hyphae, haploid, spores for
wind dispersal (asexual)
Ascospores haploid mycelia of opposite mating strains fuse and
develop spores within an ascus (sexual)
3-Phylum Basidiomycota- edible mushrooms; Basidiomycota
(basidio=little base) are filamentous fungi composed of hyphae and
produce sexual spores (basidiospores); includes Coprinus
stipecapGills- plates within the cap of the basidiomycetes where
spores are producedLab exercise-observe Coprinus
In response to environmental stimuli, the mycelium reproduces
sexually by producing fruiting bodies called basidiocarps; spores=
basidiosporesbasidiocarp