Plant Diversity, Structure, and Nutrition: Study Guide for BIO 112 (Ch. 29, 30, 35–37)

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Plant Diversity and Evolution

Traits of Plants

Plants are multicellular, eukaryotic, and primarily photosynthetic organisms that have evolved a variety of adaptations for terrestrial life.

Cell wall composition: Made of cellulose, providing structural support.
Chloroplasts: Contain chlorophyll a and b for photosynthesis.
Alternation of generations: Life cycle alternates between haploid and diploid stages.
Adaptations for land: Cuticle, stomata, vascular tissue in some groups.

Alternation of Generations

This term describes the plant life cycle, which alternates between two multicellular stages:

Gametophyte (n): Produces gametes by mitosis.
Sporophyte (2n): Produces spores by meiosis.

Example: In mosses, the gametophyte is dominant; in ferns and seed plants, the sporophyte is dominant.

Major Plant Groups and Their Characteristics

Nonvascular Plants (Bryophytes)

No vascular tissue (xylem or phloem).
Dominant gametophyte stage.
Require water for fertilization.
Examples: Mosses, liverworts, hornworts.

Seedless Vascular Plants

Have vascular tissue (xylem & phloem).
Dominant sporophyte stage.
Still require water for fertilization.
Examples: Ferns, horsetails, club mosses.

Gymnosperms

"Naked seeds" (not enclosed in fruit).
Dominant sporophyte stage.
Examples: Conifers, cycads, ginkgo.
Male cones produce pollen; female cones produce ovules.

Angiosperms

Flowering plants; seeds enclosed in fruit.
Dominant sporophyte stage.
Double fertilization: embryo (2n) & endosperm (3n).
Examples: Grasses, trees, crops.

Summary Table: Major Plant Groups

Group	Vascular Tissue	Seeds	Dominant Generation	Examples
Bryophytes	No	No	Gametophyte	Mosses, liverworts
Seedless Vascular	Yes	No	Sporophyte	Ferns, horsetails
Gymnosperms	Yes	Yes	Sporophyte	Conifers, cycads
Angiosperms	Yes	Yes	Sporophyte	Flowering plants

Selected Plant Phyla

Cycadophyta: Cycads; palm-like, ancient group.
Gnetophyta: Includes Ephedra, Gnetum, Welwitschia; unusual gymnosperms.
Ginkgophyta: Ginkgo biloba; fan-shaped leaves, pollution tolerant.
Coniferophyta: Pines, firs, spruces; largest gymnosperm group.
Anthophyta: Angiosperms; flowering plants.
Bryophyta: Mosses; nonvascular, gametophyte-dominant.
Pterophyta: Ferns; seedless vascular plants.
Hepatophyta: Liverworts; reproduce using gemma cups.
Anthocerophyta: Hornworts; elongated sporophyte.

Plant Life Cycles and Reproduction

Life Cycle: Angiosperms vs. Pines

Both angiosperms and gymnosperms (pines) have alternation of generations, but differ in reproductive structures and processes.

Angiosperms: Flowers produce pollen and ovules; double fertilization forms embryo and endosperm; seeds develop in fruit.
Pines: Separate male (pollen) and female (ovulate) cones; single fertilization; seeds develop in cones.

Similarities: Both produce pollen, seeds, and have dominant sporophyte generation.

Differences: Angiosperms have flowers and fruit; double fertilization is unique to angiosperms.

Dominant Land Plants

Angiosperms are the most dominant land plants today.

Largest and Oldest Land Plants

Giant sequoia (largest)
Bristlecone pine (oldest)

Seed-Producing Plant Groups

Gymnosperms and Angiosperms produce seeds.
Seedless: Bryophytes & seedless vascular plants.

Sporophytes vs. Gametophytes

Term	Ploidy	Function	Example
Sporophyte	2n	Produces spores by meiosis	Fern plant, pine tree, flowering plant
Gametophyte	n	Produces gametes by mitosis	Moss plant, fern prothallus, pollen grain

Parts of a Flower

Petals: Bright, attract pollinators.
Calyx: All sepals together; protect flower bud.
Stamen (male): Anther (makes pollen), filament (supports anther).
Carpel/Pistil (female): Stigma (sticky surface for pollen), style (tube leading to ovary), ovary (contains ovules; seeds develop here).

Fruit, Cone, and Seed

Fruit: Mature ovary enclosing seeds (angiosperms).
Cone: Reproductive structure in gymnosperms.
Seed: Embryo + stored food + protective coat.

Microspores, Megaspores, Male & Female Gametophytes

Microspores: Male gametophyte (pollen).
Megaspores: Female gametophyte (embryo sac).
Male gametophyte: Pollen grain.
Female gametophyte: Ovule's embryo sac.

Mycorrhizae

Symbiotic associations between fungi and plant roots that improve water and nutrient uptake.

Monocots vs. Dicots

Feature	Monocots	Dicots
Cotyledons	1	2
Leaf Venation	Parallel	Netlike
Vascular Bundles	Scattered	Ring
Roots	Fibrous	Taproot
Flowers	Multiples of 3	Multiples of 4 or 5

Plant Structure and Function

Plant Structures

Apical meristems: Tips of roots & shoots; primary growth.
Ramification: Branching of roots/shoots.
Primary tissues: Produced from apical meristem.
Secondary tissues: Produced from lateral meristem (cambium).
Root: Anchors plant, absorbs water/nutrients.
Shoot: Above-ground portion; photosynthesis, support.
Leaf: Photosynthesis organ.
Fibers: Long, supportive cells (sclerenchyma).
Tracheids: Water-conducting cells (xylem).
Stomata: Openings for gas exchange.

Dermal, Ground, and Vascular Tissue

Dermal: Protection, outer covering.
Ground: Parenchyma (storage), collenchyma (support), sclerenchyma (rigid support).
Vascular: Xylem (water) & phloem (sugars).

Primary vs. Secondary Growth

Primary growth: Lengthening of roots/shoots (apical meristems).
Secondary growth: Thickening (lateral meristem, cork cambium).

Transport and Nutrition in Plants

Water Movement Through Plants

Water enters roots via osmosis.
Moves upward through capillary action, cohesion & adhesion.
Pulled upward by transpiration from leaves.

Transpiration vs. Root Pressure

Transpiration: Evaporation from leaves pulls water upward.
Root pressure: Pushes water upward when soil is moist.

What is Sap?

Sap is the sugar-rich fluid carried in phloem (sometimes refers to xylem fluid too).

Plant Nutrients

Macronutrients: Needed in large amounts: C, H, O, N, K, Ca, S, Mg
Micronutrients: Needed in trace amounts: Fe, Mn, Zn, Cu, B, Cl, Mo, Ni

Nitrogen Fixation

Nitrogen fixation is the conversion of atmospheric N2 gas to ammonia (NH3), making nitrogen available to plants.

Performed by Rhizobium bacteria (in legume root nodules), Cyanobacteria, and some free-living soil bacteria.

Equation:

Soil Layers

Layer	Description
O Horizon	Organic matter (leaves, humus)
A Horizon	Topsoil: minerals + organic material, most roots
E Horizon	Leached minerals accumulate
B Horizon	Minerals from above accumulate
C Horizon	Weathered parent rock
R Horizon	Solid bedrock

Additional info: These notes cover key concepts from chapters on plant diversity, structure, transport, and nutrition, suitable for General Biology students preparing for exams.