Comprehensive Plant Biology: From Photosynthesis to Gymnosperms and Conifers

1) What is the role of plants in the ecosystem?

Producers — they photosynthesize, converting sunlight into energy that supports food chains. They also produce oxygen, retain soil, and cycle nutrients.

2) What does the term Embryophyte mean?

Plants that have a multicellular, dependent embryo — the embryo is retained within the female gametophyte and receives nutrients from the parent plant.

3) What types of organisms are now NOT classified in the Kingdom Plantae?

Algae (including green algae) — they were once grouped with plants but are now classified separately (mostly in Protista or their own kingdoms).

4) What are the characteristics of plants?

1) Alternation of generations 2) Multicellular, dependent embryos 3) Walled spores (with sporopollenin) 4) Multicellular gametangia (gamete-producing structures) 5) Apical meristems (regions of active growth at tips)

5) What is a stomata?

A pore in the surface of a leaf or stem that allows gas exchange (CO2 in, O2 out) and is involved in water regulation via opening/closing.

6) What are some advantages & disadvantages of moving onto land?

Advantages: More CO2, direct sunlight, more nutrients, initially fewer herbivores & pathogens. Disadvantages: Scarcity of water, lack of structural support.

7) In Geological Terms — What was the 'age' of Plants? (when did plants first arise?)

Plants have been around for approximately 475 million years, arising in the Paleozoic Era (Ordovician period). They diversified greatly during the Devonian and Carboniferous periods.

a. What was unique about the atmosphere during this time period?

The atmosphere had higher CO2 levels. As plants spread and photosynthesized heavily, they eventually helped lower CO2 and cool the planet.

8) What did most of the plants found during this time period turn into when they died?

Coal — the decaying plants of Carboniferous forests eventually became coal (a fossil fuel).

9) What did modern day plants arise from?

Modern plants evolved from green algae. The closest living relative is Charophytes (Green Algae) — specifically the group called Charophyta, which inhabit shallow waters around ponds and lakes.

Avascular Seedless Plants (Bryophytes)

10) Know all of the types of plants found in this clade.

Three phyla: • Phylum Hepatophyta — Liverworts (~9,000 species) • Phylum Anthocerophyta — Hornworts (~100 species) • Phylum Bryophyta — Mosses (~15,000 species)

11) How tall do avascular plants grow? Why?

They are very short/small. Because they lack vascular tissue (xylem and phloem), they cannot transport water and nutrients efficiently over long distances, so height is constrained.

12) Are avascular plants found in dry or moist environments? Why?

Moist environments (rainforests, wetlands). They depend on water for reproduction — their flagellated sperm must swim through water to fertilize eggs.

13) What is peat moss used for?

Sphagnum (peat moss) is harvested as peat, used as a fuel source and in horticulture/gardening. It forms extensive deposits of partially decayed organic material.

14) What nutrient does it store?

Carbon — Sphagnum/peat is an important global reservoir of organic carbon.

15) What is unique about the ecosystem it is found in?

Peat bogs are acidic, oxygen-poor environments that slow decomposition, which preserves organic material extremely well.

a. What was the Tollund Man?

A bog mummy — a naturally preserved human body found in a peat bog in Denmark, preserved for thousands of years due to the acidic, oxygen-poor conditions of the bog.

Vascular Seedless Plants

1. Know the 2 Clades in this group & the types of plants found in each clade.

Phylum Lycophyta: Club mosses, Spike mosses, Quillworts Phylum Monilophyta (formerly Pteridophyta): Ferns, Horsetails, Whisk ferns

2. Are Club mosses & Spike mosses real mosses?

No — they are NOT true mosses. They have vascular tissue, unlike true mosses (bryophytes).

3. How many living species of Quillworts exist?

Only 1 extant genus of Quillworts.

4. Which type of moss's spores were used by magicians & photographers?

Club moss spores — they are rich in oil and were ignited to create smoke or flashes of light.

5. The Phylum Pterophyta is made up mostly of what plant type?

Ferns — they are the most diverse seedless vascular plants with more than 12,000 species.

6. Why are Horsetails called arthrophytes?

Because they are 'jointed plants' — arthro = joint. Their stems have distinct jointed segments and are the main site of photosynthesis.

7. What is the name of the only genus left in the Horsetail Clade?

Equisetum — all modern horsetails belong to this single genus.

Vascular Seed Plants (General)

16) How did seeds change the course of plant evolution?

Seeds allowed plants to: • Remain dormant for days to years until conditions are favorable • Be transported long distances by wind or animals This made seed plants far more successful on land than spore-only plants.

17) What is a seed made up of?

An embryo + nutrients (cotyledon/endosperm) surrounded by a protective seed coat.

Vascular Seed Plants

Gymnosperms

1. What are the Clades in the Gymnosperm Phylum and what plants are found in them?

• Cycadophyta — Cycads (palm-like, large cones) • Ginkgophyta — Ginkgo biloba (only 1 living species) • Gnetophyta — Gnetum, Ephedra, Welwitschia • Coniferophyta — Conifers (pine, fir, redwood, etc.) — largest phylum

2. Where in the world do Gymnosperms dominate?

Northern latitudes — cone-bearing conifers dominate boreal/taiga forests of northern North America, Europe, and Asia.

3. When did Cycadophyta predominate?

During the Mesozoic Era (age of dinosaurs) — they were a major food source for dinosaurs.

a. Why are they the most endangered of all gymnosperm plants?

75% of cycad species are threatened due to habitat destruction.

4. Why do we plant Ginkgophyta trees in cities?

Ginkgo biloba has a very high tolerance to air pollution, making it ideal for urban planting.

a. Why do we only plant Male Trees in cities?

Female trees produce seeds with a rancid/foul smell, so only males are planted in urban areas.

b. How many species are left in the Ginkgophyta clade?

Only 1 living species: Ginkgo biloba.

c. Be able to ID the Ginkgo leaf by its shape.

Fan-shaped (bilobed) leaf with parallel veins — distinctly notched in the middle.

5. What is unique about Welwitschia?

It has the largest known leaves, lives thousands of years, and is found only in the desert of southwestern Africa. It grows only 2 leaves its entire life.

6. What is the plant Ephedra used to treat?

Used as a decongestant (Ephedrine) — also known as 'Mormon tea.' Found in desert regions worldwide.

7. Know the various types of Coniferous trees discussed

a. Which one was considered extinct?

Wollemi Pine — thought to be extinct, rediscovered in 1994 outside Sydney, Australia. Only ~40 trees exist.

b. Which one is the oldest (species)?

Bristlecone Pine — found in the White Mountains of California, living 4,600+ years.

c. Which one is the tallest?

Redwood — found only along a small section of northern California and southern Oregon.

d. Which one produces blue fleshy sporophylls?

Juniper — its 'berries' are actually ovule-producing cones with fleshy sporophylls.

e. Which one is used for lumber and predominates in Northern US & Canada?

Douglas Fir.

f. What is the name of the Oldest Living Tree?

Methuselah — a Bristlecone Pine, ~4,841 years old. Its location is kept secret to protect it.

g. What was the oldest tree and what happened to it?

Prometheus — a Bristlecone Pine, ~4,862 years old at death. It was cut down by researchers in 1964.

h. Which one is found in Europe and loses its needles in the fall?

European Larch — native to Europe (near the Matterhorn), survives -50°C, and is deciduous (sheds needles in autumn).

8. How many years does it take for a pine cone to reach maturity?

Nearly 3 years from cone production to mature seed.

9. Know that there are male and female pine cones.

Male (pollen) cones are small and produce pollen/microspores. Female (ovulate) cones are the familiar large cones and contain ovules/seeds.

10. What is necessary to release the seeds from a fertilized pine cone?

Fire (heat) — heat breaks the waxy resin coating on some cones (called serotinous cones), releasing the seeds. This is an adaptation to fire-prone environments.

Seed Vascular Plants

Angiosperms

1. Why are angiosperms the most diverse group of plants now?

Because of flowers and fruits — flowers enable efficient pollination by insects and animals, and fruits aid in long-distance seed dispersal. This led to massive diversification (~300,000+ species).

2. What is the purpose of a flower?

Sexual reproduction — flowers attract pollinators and house the male and female reproductive structures (stamens and pistils/carpels) for fertilization.

3. Know the anatomy of a flower (Lab).

Key parts: • Petals — attract pollinators • Sepals — protective outer leaves • Stamen (anther + filament) — male; produces pollen • Pistil/Carpel (stigma + style + ovary) — female; contains ovules • Receptacle — base where flower attaches to stem

4. Know the different methods of pollination.

• Biotic: insects (bees, butterflies), birds (hummingbirds), bats, other animals • Abiotic: wind pollination (common in grasses and many trees)

5. Know the different methods of seed dispersal.

• Wind — winged or feathery seeds (maple, dandelion) • Animals (external) — hooks/burrs that cling to fur • Animals (internal) — eaten in fruit, seeds pass through digestive tract • Water — floating seeds • Mechanical — plants that explode to launch seeds

6. Know the differences between Monocots & Eudicots (Dicots)

a. Types of characteristics used to ID

: Monocots: 1 cotyledon, parallel leaf veins, vascular tissue scattered, floral parts in 3s, fibrous root system, pollen with 1 opening Eudicots: 2 cotyledons, netlike leaf veins, vascular tissue in ring, floral parts in 4s or 5s, taproot, pollen with 3 openings

b. Types of plants found in each category / most important food crops

: Monocots (70,000 species): Grasses, Maize (corn), Rice, Wheat, Palms, Orchids — MOST food crops are monocots Eudicots (170,000 species): Legumes (peas, beans), Roses, Strawberries, Apples, Pears, Deciduous trees (walnut, oak, maple)

7. Which types of plants do not fit into the Mono/Eudicot profile?

Basal angiosperms (oldest lineages): Amborella trichopoda, water lilies, star anise Magnoliids: Magnolias, laurels, black pepper — more closely related to monocots/eudicots but don't fit either category cleanly