Botany exam 2

Define the term algae

aquatic photosynthetic protistans

What are the four basic morphological forms of algae?

unicellular, filamentous, colonial, or thallose

Describe (diagram with labels) the general life cycle of plants, including: alternation of generations, haplontic, diplontic. Make sure you know how to distinguish between each

What prokaryotic group of organisms might be considered as algae?

cyanobacteria (blue-greens)

Contrast the terms isomorphic and heteromorphic.

Isomorphic: both forms gametophyte and sporophyte, may look alike

- Example: sea lettuce

Heteromorphic: the two forms look different

- Example: kelp

Describe the basic characteristics of the algal Divisions

Chlorophyta, Chromophyta, Rhodophyta, Euglenophyta, and Dinophyta.

For each algal division, contrast the features relative to: a) pigments, b) cell wall structure, and

c) photosynthetic products (energy storage molecules)

DIVISION DINOPHYTA - dinoflagellates

General Characteristics:

a) Photosynthetic pigments - chlorophylls a & c, peridinum (a carotenoid)

o gives them a brownish color

b) Cell Wall - cellulose plates; contains two grooves (or furrows): transverse & longitudinal

o some also contains spines

c) Carbohydrate storage molecule - starch + lipids

- Are mostly marine

- Many species are Bioluminescent produce light when disturbed

DIVISION EUGLENOPHYTA - euglenoids (pp. 339-340)

General Characteristics:

a) Photosynthetic pigments - chlorophyll a & b, carotenoids (some forms without chloroplasts)

b) Cell Wall – no cellulose; instead, a flexible structure of protein = Pellicle

c) Carbohydrate storage molecule – paramylon

- Common freshwater algae that can produce dense colonies in high nutrient areas

DIVISION CHLOROPHYTA - Green algae (pp. 327-333)

General Characteristics:

a) Photosynthetic pigments - Chlorophylls a & b, carotenoids

b) Cell Wall – cellulose

c) Carbohydrate storage molecule – starch

- Both freshwater and marine species

- Wide variation in organism size: unicellular, filamentous, colonial, and thallose

DIVISION RHODOPHYTA - Red Algae

a) Photosynthetic pigments - chlorophylls a & d, phycoerythrin, phycocyanin

b) Cell Wall - of cellulose with secretion of gelatinous polysaccharides

c) Carbohydrate storage molecule - floridean starch

- Mostly red algae, are marine and of tropical deep waters (up to 200 m)

- Very complex life cycle with three different forms

DIVISION CHROMOPHYTA - yellow-green, golden-brown, brown & diatoms

General Characteristics:

a) Photosynthetic Pigments - chlorophylls a & c, fucoxanthin (type of xanthophyll)

o give them a yellowish to brown color

b) Cell Wall – cellulose

o some with no cell wall

c) Carbohydrate storage molecule – laminarin

What are some economic uses of algin (alginic acid)?

Ice cream stabilizer, .Thickening agent, Beer production, Gelling agent, wound dressings, dental impressions, drug delivery, heartburn relief, toothpaste binder, cosmetic creams, face masks, textile printing, paper coating, welding rods

Describe the life cycle of the rockweed Fucus, why is it unusual for brown algae?

diplontic life cycle, Fucus is diplontic and heterogametic

most brown algae have an alternation of generations life cycle and are homogametic

Contrast the typical habitat (where they live) for the brown and red algae

Brown algae is mostly marine and in cooler climates, Mostly red algae are marine and of tropical, deep waters

Describe the general life cycle of red algae.

Three components in life

• The gametophyte grows and produces gametes by mitosis (spermatia and eggs)

• Fertilization produces the zygote, which grows to produce the carposporophyte, still attached to the gametophyte

• Carpospores are produced by mitosis, grow into the tetrasporophyte that produces tetraspores by meiosis → new gametophyte

Why is its life cycle considered to be unusual? (red algae)

unusual sporophyte attached to the gametophyte (carposporophyte) and other separate (tetrasporophyte)

What is the "red tide"; what organisms are the cause?

Why do we need to be concerned about a red tide?

Harmful algal bloom (HAB), which happens when microscopic algae multiply rapidly and grow out of control in coastal waters. Waves can break open the algae cells and release toxins into the air, causing coughing, eye irritation, and breathing difficulties

Red tide is caused by overgrowing of dinoflagellates, releasing toxins and reducing oxygen leaves in water at night – create problems for many organisms

Relative to Pfisteria piscicida:

Why is it dangerous to us?

In what ways are the outbreaks predictable?

is dangerous because its toxic compounds can become airborne or directly penetrate tissues. Humans are exposed primarily by breathing in water mist/aerosols near active fish kills or through direct skin contact with contaminated water

Characterize the mosses, liverworts, and hornworts?

Include the Division names.

Mosses – Division Bryophyta

* gametophyte leafy and grows vertically

* gametophyte with some elongate water conducting tissues present (on “stems”)

* gametophyte reproductive organs not stalked

* sporophyte with columnella

Liverworts – Division Hepaticophyta

* commonly thallose and grows flat on substrate

* no elongate water conducting tissues present

* gametophyte develops stalked reproductive organs

* sporophyte small, lacks columnella within capsule

Hornworts – Division Anthocerophyta

* gametophyte thallose and grow flat on substrate

* no elongate water conducting tissues present

* gametophyte reproductive organs not stalked

* sporophyte elongate with columnella

Describe the sexual reproductive process in mosses.

antheridia produce sperm by mitosis  they swim in water

archegonia produce eggs

egg + sperm → zygote

Describe and/or draw & label the structure of the moss sporophyte

embryo develops a long stalk = setum

spores produced in terminal capsule

within capsule is columnella (central internal stalk)

top of capsule - operculum with peristome teeth that are hygroscopic

What are the unusual features of sphagnum?

What are its economic uses?

grows in peat bogs which produce peat moss produces an acidic pH stems filled with many water-filled spaces which allow for water holding during drought.

How might a liverwort reproduce asexually?

1) dichotomous branching

2) gemmae cups produce little multicellular propagules

What are antheridiophores and archegoniophores?

Antheridiophores - produce antheridia on upper surface

Archegoniophores - produce archegonia on lower surface

Define the following terms relative to bryophytes. Include to which groups the terms apply.

capsule, dichotomous branching, elaters, operculum, protonema, sterile jacket layer

capsule structure includes spores (produced by meiosis) found in all bryophytes

elaters: hygroscopic and aid dispersal of spores but only in the liverworts

dichotomous: commonly have distinct equal branching a growth pattern for all bryophytes

operculum: with peristome teeth that are hygroscopic on the top of capsule only in mosses

protonema: spores germinate into juvenile plants of the mosses

sterile jacket layer: outer surfaces produces antheridia non reproductive cells on all bryophytes

Describe the sporophytes of hornworts.

Zygote develops into the sporophyte on gametophyte

structures include: a) foot, b) stalk, c) capsule

capsule includes spores (produced by meiosis) and

central support with the columnella