Auburn University BIOL 1030 (Organismal Bio) Prof. Choi- FINAL EXAM STUDY GUIDE

EXAM 1

PHYLOGENY

phylogeny

Evolutionary history of a species or group of species.

systematics

study of evolutionary relationships between organism(s). Very dynamic scientific field!

biological discipline focused on classifying organisms and determining those evolutionary relationships

biodiversity

all of the diversity/variety of life on Earth.

taxonomy

the science of naming organisms.

taxon/taxa

a named group of organisms

classification

assigning organisms to meaningful, hierarchical groups (like genera or families)

phylogeny

evolutionary history of an organism(s); where things originate; ancestry

constructed using systematics

paraphyletic

"beside the tribe"

Consists of an ancestral species and SOME, but not all, of its descendants

polyphyletic

"many tribes"

Includes distinctly related species but does not include the common ancestor

monophyletic

"single tribe"

Consists of an ancestral species AND all of its descendants

binomial naming- formatting and why it's used

always capitalize genus, always lowercase species

when typed: italicize

when handwritten: underline

why it's used

2 goals of binomial nomenclature:

1. avoid ambiguity when communicating

2. accurately reflect the organism

Hierarchical classification- "Dear King Phillip Came Over For Great Sex"- which are more/less inclusive?

ex- domain is more inclusive than family

ex- class is less inclusive than phylum

inclusivity decreases as you go down the list

how are birds classified in both Class Aves and Class Reptilia?

Some systematists have placed a species within a genus (or other group) to which it is NOT closely related!

Reason for this mistake - over the course of evolution, a species may have lost a key feature shared by its close relatives.

EXAM 1

PROKARYOTES

3 domains of life?

Bacteria, Archaea, Eukarya

domains Bacteria and Archaea are ______ cells

unicellular prokaryotic

most bacterial cell walls contain ______

peptidoglycan

gram staining

stains bacterial cells based on their cell wall characteristics

Gram positive vs Gram negative bacteria (characteristics)

Gram positive:

-stain purple

-very thick layer of peptidoglycan

-less structurally complex than gram negative cells

Gram negative:

-stain pink

-very thin layer of peptidoglycan

-more structurally complex

some unique features of bacterial cells

peptidoglycan

capsules

endospores

flagella

capsules, endospores, flagella

capsules:

-Dense, well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky

-Serves in protecting the cell

-Helps with adhering to surfaces

endospores:

-Thick-coated, resistant cell within the bacterial cell

-Made when cells are exposed to harsh conditions

flagella:

-Allows for taxis - directed movement toward/away from a stimulus

-Motility (movement)

asexual reproduction

prokaryotic repro

How does this generate genetic diversity if we don't have meiosis and fertilization processes?

-Escherichia coli (E. coli) divides every 20 minutes via binary fission.

Mutation rate: 1:10 million (seems rare, right?)

Faster division = more mutations per generation =more diversity!

horizontal gene transfer

A form of genetic recombination, where DNA is combined from different sources

Types of horizontal gene transfer (transformation, transduction, conjugation)

Transformation:

-when DNA is taken up from the external environment

Transduction:

-bacteriophages (phages) carry genetic info from one host cell to another

Conjugation:

-DNA is transferred between two prokaryotic cells via a sex pilus

photoautotroph

organisms that obtain energy from light (e.g. the sun)

Ex: photosynthetic organisms (plants, Cyanobacteria, algae)

What organelle is essential for phototrophs?

Chloroplasts

Energy source = light

Carbon source = CO2 or other related carbon source

chemoautotroph

organisms that obtain energy from chemicals (e.g., humans, some bacteria, some archaea)

deep sea vent, where archaeal cells thrive (heat, pressure).

Energy source = inorganic chemicals

Carbon source = CO2 or other related carbon source

heterotroph

organisms that require at least one organic nutrient (like glucose) to make organic compounds for energy (e.g., humans)

photoheterotroph

Energy source = light

Carbon source = organic compounds

chemoheterotroph

Energy source = organic compounds

Carbon source = organic compounds

Thiomargarita namibiensis - significance?

Can be seen with the naked eye!

Largest bacterium

Found on the coast of Namibia

Helicobacter pylori - significance?

Causes stomach ulcers

Barry Marshall drank a culture of it to prove that it causes stomach ulcers…

What is symbiosis? (mutualism, parasitism, commensalism)

(“living together”) an ecological relationship between organisms of 2 different species that live together in direct and intimate contact.

-symbiont: a smaller participant in a symbiotic relationship, living in or on another organism

-host: the larger participant in a symbiotic relationship

mutualism (+/+):

-Symbiotic relationship in which both parties benefit

-plants and pollinators

commensalism (+/0):

-Symbiotic relationship in which one party benefits and the other is neither harmed nor benefitted.

-clown fish and sea anemones

parasitism (+/-):

-Symbiotic relationship in which one party (parasite) benefits and the other (host) is harmed

-tick (parasite) and vertebrate (host)

EXAM 1

PROTISTS

What domain do protists fall under?

Eukarya

Haploid vs. diploid?

Haploid (n) = half the # of potential chromosomes

Diploid (2n) = double the # of potential chromosomes

Mitosis vs. meiosis?

sexual life cycles

Mitosis = 1 replication + 1 division = yields identical daughter cells

(Can be n-->n OR

2n-->2n)

Meiosis = 1 replication + 2 divisions = yields variety of haploid daughter cells

What is a gamete? A zygote?

Gamete – haploid (n), reproductive cells

-Can be produced by mitosis or meiosis

-Animals form gametes (sperm/egg) via meiosis

-Fungi +others can form gametes via mitosis

Zygote – always the product of syngamy (fusion of 2 gametes)

What is syngamy? What are the 2 sub-types of syngamy?

Syngamy = fusion of two cells together

1. Plasmogamy = first ½ of syngamy; cell membrane and cytoplasm fuse

2. Karyogamy = last ½ of syngamy; nuclei fuse

What is the main difference between sexual and asexual reproduction?

Meiosis yields a change in chromosome number and is therefore the difference between sexual and asexual reproduction.

-Some organisms have both.

-Asexual reproduction = mitosis only.

Gametic meiosis - definition and example?

Diploid-dominated

gametes made via meiosis

notice how asexual repro occurs while 2n

Gametes are only haploid (n) cells

-Produced by meiosis

Fusing of gametes (n) generates a diploid cell (2n)

-Diploid cells can divide by mitosis to form a multicellular organism!

ex- animals

Zygotic meiosis - definition and example?

Haploid-dominated

The zygote is the only diploid cell in the life cycle (hence, the name!)

-Undergoes meiosis (no mitosis)

-“The zygote undergoes meiosis”

Haploid cells divide by mitosis.

ex- fungi and most protists

Sporic meiosis (alternation of generations) - definition and example?

aka alternation of generations

Mitosis can occur in both haploid and diploid cells!

“Spores are produced by meiosis.”

Both a haploid and a diploid organism exist in this life cycle!

Called “alternation of generations” because of haploid gametophytes and diploid sporophytes.

ex- Seen in plants

The most complicated one

Components of a brown algae

Holdfast = anchors it down

Stipe = stem to support blades

Blade = leaflike structures

Alternation of generations (sporic meiosis) is seen!

Heteromorphic vs. isomorphic

Heteromorphic – sporophytes and gametophytes structurally different

Isomorphic – structurally same

Apicomplexa - Plasmodium spp. and malaria

alveolates

Possess an apical complex to aid in host cell penetration (parasitic)

Plasmodium spp.

-Causes malaria (“bad air”) – cycle of fever/chills – due to life cycle of Plasmodium in humans!

-Exists in both humans and mosquitoes (Anopholes spp.)

-Primary host = mosquito

-Secondary host = huma

What are pseudopodia?

Many are amoebas – protists that have pseudopodia (“fake feet”)

Radiolarians often have pseudopodia

forams: Pseudopodia extend from pores to aid in swimming, test formation, and feeding

Cercozoans- Have thread-like pseudopodia

Amoebozoans- Lobe- or tube-shaped pseudopodia (not thread-like as in rhizarians)

Plasmodial slime molds- Extends pseudopodia through soil, mulch, rotting logs

Rhodophyte literally means ________ __________.

red algae

Chlorophyte literally means ________ __________.

green algae

EXAM 1

FUNGI

Heterotroph

can’t make their own food & must obtain it from some other source

Unlike animals, though, fungi do not actually ingest (eat) their food.

Absorbing nutrients as opposed to ingesting them

Instead, fungi absorb nutrients from the environment.

Make & secrete hydrolytic enzymes that can:

-Break down complex molecules into smaller ones

-Penetrate walls of other cells to obtain nutrients that way

Decomposer

break down and absorb nutrients from nonliving organic material

-Fallen tree logs

-Animal corpses

-Organismal waste

Ophiocordyceps spp. - significance?

zombie ants

fungal nutrition:

Parasites – absorb food from cells of living hosts

-Some of these may also be pathogenic (cause diseases in plants and others that eventually cause disease in animals)

What are hyphae?

Network of tiny, connected filaments that collectively make up the mycelium of a fungus

Mycelium = mass network of hyphae in a fungus

Hyphae are divided into cells by septa (sing. septum); “cross walls”

What is a mycelium?

mass network of hyphae in a fungus

Infiltrates the material where the fungus feeds

Maximizes surface area: volume ratio

-Just a cubic centimeter of soil can contain as much as 1 km of hyphae!

Fungus prioritizes its energy and resources into adding hyphal length

Multicellular fungi are not motile

How can fungi prioritize energy and resources?

Fungus prioritizes its energy and resources into adding hyphal length

What are mycorrhizae?

specialized hyphae

intimate association of a fungus and plant roots

-Plant gets nutrients quicker

-Fungi gets organic nutrients

-What kind of symbiosis is this?

Mutualism!

mycorrhizal fungi

Fungi that form mycorrhizae (associations with plant roots)

Have two interesting ways of obtaining nutrients!

1. Ectomycorrhizal fungi – form sheaths of hyphae over surface of plant roots and can grow into extracellular spaces of root cortex

2. Arbuscular mycorrhizal fungi – extend arbuscules through root cell wall and into tubes formed by invagination (pushing inward) of the root plasma cell membrane

The point of spores?

Recall: designed for dormancy and dispersal

Can be carried long distances by wind or water

If they land in a moist place with food, they germinate and produce mycelium!

Leave a slice of watermelon exposed to the air to a week!

Zygotic meiosis

general fungal life cycle

Zygote is the only diploid organism

The zygote (2n) undergoes meiosis.

Ascomycetes

Phylum Ascomycota

Produce ascospores in saclike structures called asci (sing. ascus)

“Sac fungi”

Fruiting body = ascocarp

Asexual spores of Neurospora crassa (another bread mold) = condida

-Haploid (n)

-Produced at the tips of specialized hyphae (conidiophores)

Basidiomycetes

phylum Basidiomycota

~50,000 species (mushrooms, puffballs, shelf fungi)

Have a reproductive appendage called a basidium (pl. basidia)

-Produces sexual spores on gills of mushrooms

-Karyogamy occurs here

Important decomposers of wood + other plant material

-Best at decomposing lignin (component in wood)

Fruiting body = basidiocarp

What you see at the grocery store

What is a lichen?

Symbiotic association between a photosynthetic microorganism and a fungus!

Millions of photosynthetic cells are held in a mass of fungal hyphae

Fungal component is often an ascomycete

Recent studies have shown that there may be a second fungal component!

Photosynthetic organism (often a cyanobacterium or algae) provides carbon compounds and fixes nitrogen

Fungus provides photosynthetic partner with an environment supportive for growth (hyphae)

-Gas exchange

-Protection

-Retains water and minerals

EXAM 2

PLANT DIVERSITY I

Sporic meiosis (alternation of generations)

Sporic meiosis (alternation of generations)

-“Each generation gives rise to another”

-Sporophyte = diploid (2n)

-Gametophyte = haploid (n)

General steps:

1.Gametophyte -> gametes (n) via mitosis

2.Syngamy -> zygote (2n)

3.Zygote develops into diploid sporophytes (2n)

4.Sporophyte makes haploid spores via meiosis

5.Spores develop into haploid gametophytes (n)

What are sporangia?

Sporangia (sing. sporangium)

-Multicellular organs of sporophyte

-Produce spores

-Cell walls are made of sporopollenin

What are apical meristems?

Apical meristems

-Localized regions of cell division at the tips of roots and shoots

-Can continuously divide to increase plant’s exposure to resources

What is a cuticle?

Cuticles

-“Waterproof” covering on epidermis of many plant species

-Prevents water loss

-Protection from microbial invaders

What are stomata?

Stomata (sing. stoma)

-Specialized pores

-Allows for exchange of CO2 and O2 during photosynthesis

-Open/close depending on water requirements

how do plants differ from algal relatives?

1. sporic meiosis

2. sporangia

3. apical meristems

4. cuticles

5. stomata

Bryophyte quite literally means ________ __________.

Liverworts, mosses, and hornworts

(nonvascular plants)

moss plant

Vascular plants have 2 kinds of vascular tissue called ________ and __________.

Xylem = carries most of water and minerals

-One-way flow

-“Xy to the sky”

Phloem = carries sugars, amino acids, and other organic products

-Two-way flow

-“Go with the phlo”

General differences between gymnosperms and angiosperms

Seed-producing plants:

Gymnosperms

“Gymno-” = naked

”-sperm” = seed

Angiosperms

“Angio-” = container

Nearly 90% of living plants

Angiosperms, are also known as flowering plants and having seeds enclosed within their fruit. Whereas gymnosperms have no flowers or fruits and have naked seeds on the surface of their leaves. Gymnosperm seeds are configured as the cones.

seed: An embryo packaged with a supply of nutrients inside a protective coat

Phylum Hepatophyta quite literally means ________ __________.

liver shaped gametophytes

Phylum Bryophyta quite literally means ________ __________.

moss

Xylem and phloem

two types of vascular tissue

Homosporous vs. heterosporous

homosporous:

Most seedless vascular plants are homosporous (“one spore”)

-1 type of sporophyll that bears 1 type of sporangium that produces 1 type of spore

-In other words… the gametophyte produces both eggs and sperm

heterosporous:

Some other vascular plants are heterosporous (”different spores”)

-Include ALL seed-producing plants

-2 types of sporophylls (leaves that bear sporangia [structures that produce spores]):

-Megasporophylls – make megaspores à female gametophytes

-Microsporophylls – make microspores à male gametophytes

EXAM 2

PLANT DIVERSITY II

Why do seed plants make up the vast majority of plant biodiversity?

adaptations:

1. reduced male and female gametophytes (size)- develop within parental sporophytes, protected from environmental stress

2. pollen- protects male gametophytes (which produce sperm) and can be transported by wind or animals

3. ovules- protect female gametophytes (which produce eggs)

4. an ovule fertilized by pollen develops into a seed

all with the ultimate goal of protection

Gymnosperm vs. angiosperm

2 groups of seed-producing plants:

Gymnosperms

“Gymno-” = naked

”-sperm” = seed

Angiosperms

“Angio-” = container

Nearly 90% of living plants

What is a seed?

An embryo packaged with a supply of nutrients inside a protective coat

What are some terrestrial adaptations for seed plants?

Adaptations:

Production of seeds

Reduced gametophytes (thus, larger sporophytes)

Heterosporous (producing different kinds of spores)

Ovules

Pollen

allowed for:

Coping with environmental conditions

Drought

UV radiation

Water not necessary for reproduction

Required for spores, but not for seeds!

Gametophyte vs. sporophyte relationship in seed plants

Seed-producing plants (gymnosperms and angiosperms) are sporophyte-dominated

-Gametophyte has become microscopic and dependent upon the sporophyte

heterosporous

seed producing plants are heterosporous

Heterosporous = capable of producing 2 different kinds of spores

homosporous

most seedless plants are homosporous

ovules

(gymnosperms)

“Female” gametophyte with ovary

Seed plants retain (hold on to) the megasporangium within the parent sporophyte.

Ovule (“little egg”) – develops within the ovary of a seed plant and contains the female gametophyte

pollen

“Male” gametophyte held within pollen wall

Held within the pollen grain – isn’t the entire pollen grain

Pollen wall made of sporopollenin (remember?)

Develops from microspore (remember?)

Pollination vs. germination

Pollination – transfer of pollen to part of a seed plant containing ovules (required for fertilization)

Germination – when pollen starts to grow into a pollen tube that is able to discharge sperm into female gametophyte (within ovule)

2 sister clades of seed plants

Gymnosperms

-Produce “naked” seeds exposed on sporophylls

-Usually form cones!

-Includes cone-bearing plants called conifers (i.e., pines, firs, redwoods)

Angiosperms

-Produce “contained” seeds

-Usually mature into fruits!

How would you describe the life cycle of a seed-producing plant?

Sporic meiosis (alternation of generations)

Ovulate cone (female, larger)

Pollen cone (male, smaller)

Pollination occurs when the pollen grain reaches the ovule

Differences between ovulate cones and pollen cones

Ovulate cone

(female, larger)

-More complex than pollen cones

-Scales = modified leaves = megasporophylls that bear megasporangia

-Within each megasporangium, megasporocytes undergo meiosis to produce haploid megaspores

-Surviving haploid megaspores à female gametophytes

-Female gametophytes have 2-3 archegonia, which can produce an egg!

Pollen cone

(male, smaller)

-Simpler structure than ovulate cones

-Scales = modified leaves = microsporophylls that bear microsporangia

-Within each microsporangium, microsporocytes undergo meiosis, producing haploid microspores.

-Each haploid microspore à pollen grain (contains male gametophyte)

What is the only surviving species of Phylum Ginkgophyta?

Ginkgo biloba (“the maiden-hair tree”)

What phylum is the most endangered of all plant groups?

Cycadophyta

Phylum Coniferophyta is the largest _____________ phylum, and it represents trees called ____________ ("to carry cones").

gymnospern, conifer

2 main characteristics of angiosperms

Angiosperm (“contained seeds”)

Most diverse and widespread of all plants

>290,000 species (about 90% of all plants)!

flowers and fruits

What is a fruit?

As seeds develop from ovules after fertilization, the ovary wall thickens, and the ovary matures into… a fruit.

Fruit - the mature ovary of a flower.

Protects the dormant seeds and often aids in their dispersal!

Ex: pea pod

Function:

Protection

Dispersal

Fleshy

Tomatoes, plums, grapes

Fruit wall = pericarp becomes soft as it ripens

Pericarp – “wall” of a fruit

Dry

Beans, nuts, grains

Examples of fruit/seed dispersal

Dandelions - wind

Maple seeds - wind

Coconuts - water

Burrs - cling to animal fur

Edible fruits - defecation

How would you describe the general life cycle of an angiosperm?

embryo growth, seed germination, sporophyte growth, flowering, and fruit production

Sporic meiosis (alternation of generations)

What is a cotyledon?

seed leaf of an angiosperm embryo

Some species have 1 (monocot), others have 2 (dicot)