Plant Structure and Diversity

All living things have common characteristics.
Plants obtain and utilize energy through specific processes.
Photosynthesis is the method through which plants create their own food.
The structure of a plant dictates its functionalities.
Essential elements required for photosynthesis include sunlight, water, and carbon dioxide.

Cell Structure:
- Composed of plant cells, characterized by unique components:
- Cell Wall: Provides structure and protection.
- Chloroplasts: Organelles where photosynthesis occurs.
- Central Vacuole: Maintains cell rigidity and stores nutrients and waste products.
- Other eukaryotic organelles: nucleus, ribosomes, mitochondria, etc.
Multicellular: Plants are multicellular organisms.
Photosynthesis Definition: Metabolic process that converts solar energy into chemical energy for plant use.

Plant Groups:
- Nonvascular Plants: Lack vascular tissue (xylem and phloem).
- Vascular Plants: Contain vascular tissue.

Do not possess vascular tissue, making them smaller in size.
Absorb water mainly through osmosis.
Do not have true leaves, stems, or roots but have thallus bodies and root-like structures called rhizoids.

Mosses:
- Dense and small, resembling a green carpet.
- Flourish in various biomes, play a role in erosion prevention.
Liverworts:
- Distinct liver-shaped lobes, preferring tropical biomes with dim light and damp soil.
- Lack stomata for gas exchange.
Hornworts:
- Characterized by horn-shaped structures, also favor tropical locales.
- Possess only one chloroplast per cell, a unique feature among nonvascular plants.

Comprised of two organ systems:
- Root System: Focused on water and nutrient absorption, anchoring the plant.
- Shoot System: Transports fluids, stores nutrients, supports leaves and new growth.

Roots: Essential for nutrient uptake and anchoring.
Stem: Facilitates fluid transport and nutrient storage; contains specialized cells for new growth.
Leaves: Capture sunlight using chloroplasts and manage gas exchange via stomata.

Dermal Tissue:
- Protective layer preventing water loss; includes epidermis and periderm.
- Cuticle: Waxy outer layer protecting the plant.
Vascular Tissue:
- Xylem: Transports water from roots to shoots.
- Phloem: Moves minerals and photosynthates from leaves to other plant parts.
Ground Tissue:
- Plays roles in metabolism, storage, and structural support;
- Parenchyma: Basic plant cells.
- Collenchyma: Provides support; flexible due to cellulose.
- Sclerenchyma: Provides rigidity (ex. apple cores).

Angiosperms:
- Seed-bearing flowering plants with reproductive structures called flowers.
- Seeds are encased in ovaries (fruits), which facilitate seed dispersal through animals.
Gymnosperms:
- Have seeds but no flowers or fruits; reproductive structures include cones,
- Seed dispersal occurs mainly through wind.
Seedless Plants:
- Lack seeds (e.g., ferns and club mosses);
- Reproduce using spores, with water aiding in spore dispersal.

Sepal: Protects the developing flower bud.
Petal: Brightly colored to attract pollinators.
Pistil: Female reproductive organs:
- Ovule: Contains the female germ cell that forms seeds post-fertilization.
- Ovary: Protects the ovule, develops into fruit.
- Stigma: Entrance for pollen at the top of the style where sperm travels.
Stamen: Male reproductive organs:
- Anther: Produces pollen on filament.
- Pollen: Male gametophyte containing sperm cells, produced both in gymnosperms and angiosperms.

Monocots:
- One cotyledon, parallel leaf veins,
- Flower petals in multiples of three,
- Fibrous root system.
- Examples: Grass, lilies, bananas, daffodils, etc.
Dicots:
- Two cotyledons, branching leaf veins,
- Flower petals in multiples of four or five,
- Taproot root system.
- Examples: Dandelions, apples, roses, etc.