PB 200 Exam 3 Review

Cyanobacteria

Also called blue-green algae or blue-green bacteria.

Have bacteriochlorophyll a, red and blue pigments, and requires moist conditions.

Importance of Cyanobacteria

• They are at the base of many aquatic food chains.

• Their rapid division under optimal conditions can significantly impact water quality. Such as with overgrowth and blooms.

• Toxin production by some species, causing neurological effects and vomiting

• Nitrogen fixation; some can converse N2 to NH3 which allows rice production

• Can cause skin irritation, such as swimmer’s itch

• A few are edible and used in body-care products, such as Spirulina and Nostoc “star jelly”

Overgrowths and blooms are stimulated by ___ and ____

N and P

Algal Body Structures

Unicellular, Thalloid, Filamentous, Colonial, Nodal

Unicellular

may be elaborate, one cell

Thalloid

sheet-like, large, flat, “seaweed-like”

Colonial

indivudals consisting of multiple cells aggregate together in a particular configuration, such as flat sheets or rounded clusters

Nodal

stem-like stuctures with distinct locations for branching

Filamentous

a single individual consisting of several or many cells, connected end-to-end to form strings or columns (strand-like)

Nodal

body arrangement has nodes like plants do

Charophyta

The Charophytes. Closest relatives to terrestrial land plants.

• Structural characteristics: some nodal, no meristems

• Novel characteristics: evolved from a common ancestor with plants

• Habitat: Lives in freshwater usually

• Economic impacts: use in agriculture as biofertilizers because of nitrogen-fixing abilities

• Environmental impact: provides oxygen for underwater habitats

Chlorophyta (Kindom Plantae)

The Chlorophytes. Called the green algae.

• Structural characteristics: large group, all have chl. a, store starch, some of the largest photosynthetic cells known, varied body form

• Novel characteristics: source of biofuels, models for understanding cell function

• Habitat: Freshwater and marine

• Economic impacts: used in food production like seaweed, source of biofuels

• Environmental impacts: key oxygen contributor through photosynthesis

Chromophyta (Kingdom Chromista)

The Diatoms, brown, golden-brown, and yellow-green algae.

1. Diatoms (Kingdom Protista)

   1. Structural characteristics: unicellular, silicon walls, grooved walls, light-reflective

   2. Novel characteristics: diatomical earth used in road sign paint and water filters, produce lipids when they die which becomes sea foam, used to control insects

   3. Habitat: both freshwater and marine

   4. Economic impact: diatomic earth is very important

   5. Environmental impact: significant role in carbon cycling and aquatic food webs

2. Brown Algae (Kingdom Protista)

   1. Structural characteristics: dark green to brown, some of the largest ones referred to as kelps, “sea grasses,” have long blades, up to 900 ft, varied body forms

   2. Novel characteristics: produces alginates which are thickeners in food products and cosmetics

   3. Habitat: marine

   4. Economic impact: produces alginates, which are used in food and pharmaceutical

   5. Environmental impact: provides habitat for marine organisms

Rhodophyta (Kingdom Protista)

The red algae.

• Structural characteristics: highly branched and thalloid, appear red because of phycobilin which is a light-harvesting pigment in low-light conditions

• Novel characteristics: Nori which is sushi wrapping, agar which is used in cooking/labs, thickeners in dairy and dressings

• Economic impact: used in a lot of food products like agar

• Environmental impact: important for coral reef ecosystems, provides support and structure

Dinophyta (Kingdom Protista)

The dinoflagellates.

• Structural characteristics: unicellular, cellulosic plates under membrane dino, facilitate mobility flagellae

• Novel characteristics: >3k identified, only some now known from the fossil record

• Habitat: both freshwater and marine

• Economic impact: associated with “red tide” which caused major economic impacts,

• Environmental impact: Pfisteria associated with 1990 fish kills in NC estuaries, causing neurogenic effects

Lichens

symbiotic asssociation between fungi and cyanobacteria or algae

• the fungi allow mineral and water absorption, while cyanobacteria allow for photosynthesis

Lichen body types

Crustose, Folose, Fruticose

Crustose

crust-like, flat, most common

Foliose

thalloid, sheet or foliage-like, most noticeable

Fruticose

bushy or string-like

Ecological/Cultural Significance of Lichens

• air quality indicators

• forage for deer and caribou

• fabric construction which makes tweeds

• dye extraction

Alternation of generations

Plants that reproduce sexually go through 2 life stages (generations) with one more dominant or conspicuous than the other. One generation is DIPLOID, and it is a sporophyte. One is HAPLOID. and it is a gametophyte.

Diploid cells undergo meiosis to form ___

spores. NOT GAMETES!!!!!

Spores will develop and mature into the ____ generation of the life cycle.

gametophyte

In the gametophyte generation, a sperm cell fertilizes an egg cell to form a zygote, which will develop into a ____

Sporophyte

Plants with a dominant gametophyte generation:

Bryophytes (mosses) and Algae

Plants with a dominant sporophyte generation:

Ferns and Allies, Gymnosperms, Angiosperms

Bryophytes

Plants with no seeds or vascular tissue. About 23,000 species.

• structurally small, only a few cm

• dominant gametophyte

• live in moist environments or may be aquatic

• have mycorrhizal associations

• colonizing organisms and good establishers

• highly variable environments

Liverworts

Small, flat gametophytes anchored by rhizoids.

• anchoring ONLY, no mass H20 absorption

• thought at one point to treat liver disease in Middle Ages

• one phylum (Hepaticophyta)

Hornworts

Small but dominant gametophyte.

• produces a hornlike sporophyte

• stomata and guard cells on sporophyte

Mosses

Bryon: moss

Three general groups based on substrate and occurence:

1. rock/granite mosses

2. peat mosses

3. true mosses

The green-mat like portion of mosses is the gametophyte generation, which is dominant.

• two types of gametophytes: those producing egg cells from archegonia (female) and those producing sperm cells from antheridia (male)

• Mosses can absorb water on the surfaces of stem and leaf-like aerial tissues

Ecological importance/human uses of mosses:

1. Colonizers: build soil with they decay

2. Where they grow: good indicators of soil conditions, high Ca2+ salinity, low pH

3. Preservative capacity

4. Fuel sources (peat mosses)

5. Antiseptic properties

6. Help prevent erosion

Fern Allies

• organisms with similar life cycle characteristics to ferns

• all reproduce by spores and have vascular tissues

Ex. Lycophytes,

Ferns

seedless vascular plants

Lycophytes (Club Mosses and Quillworts)

“Club moss” is a generic name. Better descriptors are used for each major group.

• Lycopodium (Ground pines)

  • Lycopods

  • 1-5 ft tall, have roots of mycorrhizal

  • scale-like leaves appear similar to gymnosperms

  • “running cedar”

• Selaginella (Spike mosses)

  • free-branching

  • produce small leaves, require moist habitats, some are sold as resurrection plants

• Isoetes (Quillworts)

  • resemble pen quills

  • confused with grasses

  • moist soil or boglike conditions → up to 20 cm tall

All lycophytes have unique uses:

• ornamental/decorative

• spores used as flash powders in photography

• forage for wildlife

• blood coagulate, stops bleeding

Whisk Ferns (Pteridophyta, Class Psilotopsia)

• only a few living species

• ancient organisms found in fossil record, earliest known plant to have vascular tissue

• 2 living genera

• structural features: no true roots, rhizomes anchored by rhizoids, bifurcating stems with yellow sporangia

• habitat: tropical/subtropical, usually Australia and South Pacific

Horsetails and Scouring Rushes (Pteridophyta, Class Equisetopsida)

• about 25 species

• all have roots and stems

• structural features: 5-12 feet tall, hollow, ribbed, vertical stems → photosynthetic with obvious nodes of scale-like leaves

• habitat: moist soil, clay/sand habitat, can be weedy

• Interesting human uses: scouring/cleaning implements, astringent properties

Ferns (Pteridophyta, Class Polypodiopsida)

• size: 1cm-5ft

• Habitats: variable, have swimming sperm so H2O is essential, many temperate ferns overwinter well

• Rachis is used in many ways like basket-weaving and mattress stuffing

• Some young fiddleheads edible

• Air filtration uses

• Resistant to many plant pathogens

• Tannins → leather production

• used historically to treat leprosy, diabetes, dandruff infections, fungal infections

Fern Life Cycle

Ferns have a dominant sporophyte generation with true roots, stems, and leaves. Spores are produced in sporangia on the surfaces of margins of fronds. Distinct clusers of sporangia visible on the frond surface are called sori.

• Some fronds specialized for photosynthesis, others specialized for spore production

• Gametophytes are mostly inconspicuous. Fern gametophytes also lack vascular and are anchored by rhizoids, like moss gametophytes. It is photosynthetic, however. Unlike mosses, ferns produce archegonia and antheridia on the SAME gametophyte structure, called a prothallus. But the gametophytes die after the next sporophyte generation is established, unlike mosses.

• 

Gymnosperms

Naked seeds. Seeds but no fruit.

Phylum Pinophyta (formerly Coniferophyta)

Cone-bearing. Pines, firs, junipers, etc.

• Structural features: needles arranged in clusters called mascicles, thick cuticle, compact mesophyll, resin canals, sunken stomata (reduce water loss)

• Woody stem features: resin canals, undergo secondary growth similar to dicors, increase in diameter

• NOTE: conifers and pines LACK xylem vessel elements and fibers! They only have tracheids. They have thick bark/periderm, lots of cork cells, and cope with low-intensity fires.

• Pine Reproduction: pollen cones (male) that produce sperm cells, seed cones (female) and spirally arranged bracts (base of bracts are ovules that produce female gametophyte or egg cell)

Family Pinacaea (pines)

models for studying gymnosperms structure and morphology

Length of time from pollination to seed maturity and release for pine cones

2-3 years

Example of other conifers:

• Sequoia (Sequoia sp.): largest single organisms on Earth → 580 ft tall!

• Red Cedar (Juniperus sp.): “Berries” used to flavor gin, female cones

• Deodar Cedar (Cedrus deodara): wood source used in different parts of the world for sarcophagi, strong scent

• Bald Cypress (Taxodium distichum): live in semi-aquatic environments

• Douglas Fir (Pseudotsuga mensiesii): largest fir trees, used in cabin construction → stacked log homes

• Fraser fir (Abies fraseri): Christmas tree→ mountain species

• Yews (Taxus sp.): Taxol → treats breast/ovarian cancer as chemotherapy

Cycadophyta

has two households (male and female) or “dioecious”

Ginkgophyta

Ginkgo biloba is only living member → extracts sold for medicinal purposes

Significant features and uses of gymnosperms

1. Boreal forests—cold or freezing tolerance

2. Primary invaders in succession — Mycorrhizal relationship

3. Size and longevity

4. Resistant to many pathogenic fungi and insects

5. Building materials and wood products

   1. 2 × 4’s

   2. Barrels

   3. String instruments

6. Newsprint

7. Turpentine, rosin, pitch, and tar (the “tar heel” state)

8. Wildlife shelter

9. Ornamentals: Christmas trees, bonsai

Flower

a reproductive organ in angiosperms that probably evolved most recently out of other major organs (specialized leaves) and is composed of up to 4 whorls

Floral Organ Whorls

1. Calyx

   1. all sepals (most external, develops first. may be photosynthetic, protect more interhalogen during development)

2. Corolla

   1. all petals, attract pollinators

3. Androecium

   1. all stamens, male structures, composed of anther and filament

4. Gynoecium

   1. all pistil(s), pistil is composed of stigma (receives pollen), style (elongates stigma), and ovary (contains ovules each producing an egg cell)

Pistil

A pistil may be composed of one or more carpels. If there is only 1 carpel, the structure may be called a pistil OR a carpel. If there are multiple carpels, you can call the structure a pistil.

Moncot Flower Whorls

multiples of 3

dicot flower whorls

multiples of 4 of 5

Receptacle

enlarged tip of flower peduncle where whorls attach to

peduncle

flower “stalk” or stem”, which elevates flower and connects it with the stem

Anther

produces pollen which produces sperm cells

Angiosperm Life Cycle

Inflorescence

numerous flowers in a cluster in a definite pattern

Perfect Flower

has both stamens and pistils (male and female parts)

Imperfect Flower

lacks either stamens OR pistils (is only male or female)

Complete Flower

has all 4 whorls

Incomplete flower

lacks at least 1 whorl

Monoecious

1 household. When male and female imperfect flowers appear on the same plant (ex. corn and oats)

IMPERFECT

Dioecious

2 households. When all flowers on the same individual plant are either male or female (ex. willows, cannabis, holly)

IMPERFECT

Overall function of a flower

production of offspring, yield fruits which attract seed dispersers, and yield seeds

Self-pollination

transfer of pollen from anther to stigma on the SAME plant

Cross-pollination

transfer of pollen from anther to stigma on a DIFFERENT plant

Fertilization

the union of sperm and egg cells to form a diploid zygote

Fruits form as a result of:

the thickening or enlargement of the ovary (and sometimes the receptable)

A fruit is actually a thickened ___

ovary

Seeds are fertilized ___

ovules

Major Fruit Categories

Dry (Dehiscent and Indehiscent), Fleshy (Drupes and Berries), Aggregate, Multiple, Accessory

Dry fruits

1. Dehiscent: ovary dehydrates at maturity → often thin fruit walls and split open

   1. follicles (milkweed), legumes (peas, beans, peanuts), siliques (mustard, broccoli), capsules (irises, orchids, lillies)

2. Indehiscent: not split open

   1. nuts and acorns, achenes (sunflower seeds), grains (wheat, rice), samaras (maple “wings”), schizocarps (parsley family like carrots)

Fleshy Fruits

remain hydrated at maturity.

1. Drupes (single ovule) - coconuts, cherries, peaches, walnuts

2. Berries (compound ovaries)

   1. True berries: tomatoes, grapes

   2. Inferior ovary berries: bananas, blueberries. often have remnant flower parts or scars at one end

   3. Pepos: pumpkins, squashes, have thick exocarp (rind)

   4. Hespiridium (leathery skin): most citrus, often make oils

   5. Pomes: (simple accessory fruits), pears, apples; have accessory tissues from other flower parts, the core is the ovary, and everything else develops from the flower tube around the ovary

Aggregate fruits

form from several pistils in the SAME FLOWER. The individual ovaries enlarge and fuse together.

• raspberry, blackberry, strawberry, magnolia

Multiple fruits

form from SEVERAL FLOWERS in an infloresence. The fruits from each flower fuse together to generate one larger structure.

• pineapple, fig, corn

Accessory fruits

composed of the thickened ovary wall as well as other floral organs such as the petals and/or receptacles

• ex: apple and strawberry

Angiosperms

• have vascular tissue, seeds, AND flowers

• dominant sporophyte generatoin

• most diverse phylum (300,000+ known living species)

Angiosperm consumption

• 20,000-30,000 plant species are edible out of 300,000+

• humans have eaten about 2,500 species

• current world food supply depends on only 150 species

Domestication

growing a plant and selecting for favorable characteristics, causing population to grow over time so it is more desirable to humans

Characteristics Important in Domestication

• Faster growth

• Increased biomass

• Shift in carbohydrate content

• Ability to withstand abiotic stress

• Disease resistance

• Wider growth range

Changes in Sclerification/Fibrosity

avoided in part through harvest before maturity

Plant domestication: Decrease in toxic metabolites & anti-nutrients

• Alkaloids are found in several plant families

• Glucosinolates in Brassicaeceae (bitterness)

• Lectins in legumes

• Amylase inhibitors in kidney beans, wheat, and rye

Plant domestication: Enhanced and Variable Carbohydrate Content

• Change in carbohydrate profiles, where starches are either stored or converted to mono- and disaccharides (sweeter fruits).

• Members of the Musa genus have been cultivated in part to produce a higher percentage of simple carbohydrates.

Plant domestication: Developed or increased variability in pigment

• Plastids contribute to most fruit color variation, as in bell pepper (Capsicum annum). Selection has occurred for more variation.

• Anthocyanins and betacyanins are stored in vacuoles and have anti-oxidant properties. Natural variation occurs in potato—domestication has actually reduced some variability.

Where on Earth did our modern food plants evolve?

Tracing crop plants to their centers of origin usually involves looking for:

• High varietal diversity

  • different traits based on variations in genetic composition & expression

• Co-occurrence of wild ancestors with domesticated

• Long history of crop use

• Tomatoes originated in northern regions of South America.

Germplasm

describes the variety of genetic composition of a particular species, seeds are usually how germplasm is collected and stored

• US germplasm collections are maintained by the USDA—National Germplasm System

Preserving Crop Plant Germplasm

• Some large-scale commercial crops have relatively homogeneous germplasms to ensure that plant quality and yield is consistent

• Homogeneity increases production but also can reduce the rate of survival when exposed to pests, diseases, and environmental stressors

• Conserving the germplasm of known variations in a species allows for a more complete genetic inventory, which could be useful in plant breeding

Svalbard Global Seed Vault

• A seed bank with deposits made by countries

• in Spitsbergen, Norway; ideal location due to no tectonic activity, permafrost, and elevation above sea level

• countries must also have backup collections of their own

• this vault provides a germplasm reserve should a global crisis occur

• opened Feb 2008

• capacity to store 4.5 million samples

Like plants, algae have the organelle ____, which allows them to make their own food through photosynthesis. 

chloroplast

All algae are classified under Kingdom ____ with the exception of ____ which are classified under Kingdom Plantae.

All algae are classified under Kingdom Protista with the exception of green which are classified under Kingdom Plantae.

One characteristic that unites all algae is:

they contain chlorophyll, which allows them to photosynthesize.

Some species of algae have a large complex, multicellular body called a ____.

thallus

The biggest ecological significance of algae is that......

they are primary producers

Cyanobacteria are similar to algae in that they are capable of:

Photosynthesis

The color of algae found in Phylum Rhodophyta is ___.

red

Which of the following describes algae that grow in several or many cells connected end-to-end to form strings or columns?

Filament

true or false: All algae species are green in color.

False

True or False. Ferns and moss need water as part of their reproduction.

True

Name one difference between mosses and ferns.

Ferns have vascular tissues, mosses don’t.

What do ferns need for fertilization to occur? In other words, how does sperm travel to the egg? 

Ferns need at least a film of water for fertilization to occur, since sperm cells must swim to the egg cells.