BIOL 1407 Review 3 (3)

Seedless Plants (Chapter 29)

Definitions

• Sporangium/Sporangia: Structures producing spores, crucial for the reproductive cycle of many plants.

• Gametangium/Gametangia: Structures responsible for producing gametes, the male and female reproductive cells necessary for sexual reproduction.

• Apical Meristem: Regions located at the tips of roots and shoots responsible for facilitating plant growth through cellular division.

• Homosporous: Refers to plants producing one type of spore that can develop into a bisexual gametophyte.

• Heterosporous: Refers to plants producing two distinct types of spores (microspores and megaspores), each developing into separate male or female gametophytes.

• Microspore: A spore that develops into the male gametophyte, leading to the formation of sperm cells.

• Megaspore: A spore that develops into the female gametophyte, leading to the formation of egg cells.

• Antheridia: Male gametangia that produce sperm cells in many seedless plants.

• Archegonia: Female gametangia that house the egg cells and may be involved in fertilization.

• Gemmae: Asexual reproductive structures formed in certain plants, capable of developing into new individuals.

• Stomata: Specialized openings in the leaves that facilitate gas exchange, allowing for transpiration and photosynthesis.

• Protonema: The initial filamentous stage of moss spores' development, which grows into the mature gametophyte.

• Rhizoids: Root-like structures that anchor non-vascular plants and help with water absorption.

• Rhizome: An underground stem that can produce new shoots and contribute to vegetative reproduction.

• Xylem: Vascular tissue responsible for transporting water and nutrients from the roots to the rest of the plant.

• Phloem: Vascular tissue that transports sugars and other metabolic products downward from the leaves.

• Microphyll: A leaf structure with a single vein, typical of certain vascular plants like lycophytes.

• Megaphyll: A more complex leaf structure with multiple veins, characteristic of ferns and other vascular plants.

• Sporophyll: A leaf that is specifically adapted for the production of spores.

• Strobili: Cone-like reproductive structures in some plants that house sporangia.

• Prothallus: The gametophyte stage in ferns, typically a small, flat structure that can be photosynthetic.

• Bryophytes: Non-vascular land plants such as mosses, liverworts, and hornworts, known for their reliance on water for reproduction.

• Tracheophytes: Vascular plants that include ferns, gymnosperms, and angiosperms, characterized by the presence of xylem and phloem.

Traits for Adaptation to Land

• Protective Cuticle: A waxy layer on the surface of leaves that helps prevent water loss and protect against desiccation.

• Stomata: Openings that regulate gas exchange, crucial for photosynthesis and respiration in terrestrial environments.

• Structural Support Mechanisms: Features like lignin in cell walls provide rigidity and support, enabling plants to grow taller and compete for sunlight.

• Reproductive Mechanisms: Development of adaptations such as pollen allows for fertilization without the need for standing water, facilitating reproduction in a variety of environments.

Kingdom Plantae Groups Characteristics

• Bryophytes: Non-vascular plants that thrive in moist habitats; they exhibit a dominant gametophyte stage in their life cycle. Examples include mosses and liverworts.

• Lycophyta: Vascular plants with microphyll leaves; they have a dominant sporophyte stage.

• Pteridophyta: Vascular ferns characterized by megaphyll leaves; they also have a dominant sporophyte stage and require water for reproduction.

• Gymnosperms: Seed-producing plants that do not produce flowers; they have a dominant sporophyte stage and include conifers like pines.

• Angiosperms: Flowering plants that produce seeds enclosed in fruits; they also exhibit a dominant sporophyte stage and demonstrate a wide variety of adaptations.

Alternation of Generations

• Homosporous Plants: Produce a single type of spore that develops into a bisexual gametophyte capable of producing both male and female gametes.

• Heterosporous Plants: Produce two distinct types of spores, leading to the development of separate male (microspores) and female (megaspore) gametophytes.

Phylum Characteristics

• Bryophyta: Dominant gametophyte, examples include mosses that reproduce by spores.

• Hepatophyta: Liverworts that exhibit a flat thallus and a dominant gametophyte generation.

• Anthocerophyta: Hornworts known for their unique elongated sporophyte.

• Lycopodiophyta: Clubmosses characterized by the presence of strobili.

• Psilotophyta: Whisk ferns that lack true leaves and demonstrate unique evolutionary traits.

• Sphenophyta: Horsetails with jointed stems that also contain silica in their tissues, providing structural support.

• Pteridophyta: Ferns with large megaphylls that display a dominant sporophyte phase in their life cycle.

Importance of Bryophytes

• Soil Erosion Prevention: Bryophytes are essential for stabilizing soil, preventing erosion in fragile ecosystems.

• Habitat Creation: They provide habitats for various organisms, fostering biodiversity in ecosystems.

• Nutrient Cycling Contribution: Bryophytes play a key role in nutrient cycles, aiding the decomposition and recycling of organic matter.

Dominance of Generations

• Bryophytes: Exhibit a dominant gametophyte generation, which is typically the most recognizable part of the plant.

• Lycophytes/Pteridophytes: Both have a dominant sporophyte generation.

• Gymnosperms/Angiosperms: Also demonstrate a dominant sporophyte generation, which is crucial for their reproductive success.

Seed Plants (Chapters 30)

Definitions

• Spermatophytes: Commonly known as seed plants, encompassing both gymnosperms and angiosperms.

• Monoecious: A term describing plants that have both male and female reproductive structures on the same individual, allowing for self-fertilization.

• Dioecious: Refers to species that have individual plants that are either male or female, necessitating cross-pollination for reproduction.

• Integuments: Protective layers surrounding the ovule that develop into the seed coat upon fertilization.

• Resin: A sticky secretion produced by some plants; serves various roles including defense against herbivores and pathogens.

Key Evolutionary Factors for Gymnosperms

• Development of Seeds: The evolution of seeds has allowed gymnosperms to protect and nourish the developing embryo, enhancing survival rates.

• Pollen Evolution: The adaptation of pollen allows for fertilization processes without relying on water, enabling reproduction in diverse terrestrial habitats.

• Adaptation to Drier Environments: Gymnosperms have evolved to thrive in arid conditions, making them prevalent in various ecosystems around the world.

Ovule Differences

• Gymnosperm Ovule: Generally exposed on cone scales; these do not undergo double fertilization.

• Angiosperm Ovule: Enclosed within an ovary, involving complex processes including double fertilization.

Seed Composition

• Structures: Typical seeds are composed of a seed coat, endosperm (nutrient storage), and embryo (developing plant).

• Origin: The structures of seeds are derived from ovule components, reflecting the complexity of angiosperm reproduction.

Pollen Purpose

Pollen's primary role is to facilitate reproduction by transferring sperm cells to ovules for fertilization, allowing for genetic diversity within plant populations.

Gymnosperm Characteristics

• Characterized by being cone-bearing plants with needle-like leaves, adapted to survive in dry and cold environments.

Phyla Characteristics of Gymnosperms

• Cycadophyta: Plants with a palm-like appearance, mainly found in tropical regions.

• Ginkgophyta: Includes Ginkgo biloba, known for its fan-shaped leaves and unique reproductive structures.

• Gnetophyta: A diverse group that includes ephedra, exhibiting unique adaptations.

• Coniferophyta: The largest phylum of gymnosperms, featuring conifers that are well-suited to various environments with needle-like leaves.

Gymnosperm Life Cycle

The gymnosperm life cycle is dominated by the sporophyte generation, with seed development stemming from the fertilized ovule.

Characteristics of Phylum Anthophyta

• Angiosperms are distinguished by their flowers, fruits, and broad leaves, showcasing a wide range of adaptations to their environments.

Angiosperm Life Cycle

In the angiosperm life cycle, pollination leads to fertilization, with seeds subsequently developing within the protective fruit structures.

Flower Parts and Functions

• Sepals: Serve to protect the developing bud before it opens.

• Petals: Often brightly colored, these attract pollinators for successful reproduction.

• Stamens: Represent the male sex organ of the flower, where male gametophytes (pollen) are produced.

• Carpels: The female sex organ that contains the ovary where ovules develop.

Fruit Functions

The primary roles of fruit include protecting seeds, aiding in their dispersal, and nourishing developing seeds through specialized structures.

Seed Dispersal Methods

• Methods of Seed Dispersal: Include wind, water, animals, and the explosive mechanism of certain fruits, all contributing to the wider distribution of plant species.

Monocots vs. Dicots

• Germination: Monocots and dicots differ in their seed structures, primarily the type and number of cotyledons.

• Growth Patterns: They also differ in characteristics like leaf venation patterns, root structures, and flower arrangements, affecting their ecological roles.

Fruit Structure

Consists of the ovary wall and surrounding tissues, which develop post-fertilization from the flower's ovary.

Types of Fruits

• Fleshy Fruits: Include berries and drupes that are juicy and often eaten by animals to aid in dispersal.

• Dry Fruits: Include achenes and nuts, which may utilize different strategies for seed release and dispersal.

Plant Classification

• Recognize the distinction between basal angiosperms, monocots, and dicots, as these classifications dictate plant characteristics and adaptations.

Monocots vs. Dicots Breakdown

• Leaves: Monocots feature parallel venation, while dicots display netted venation patterns.

• Stems: Vascular bundles are scattered in monocots, whereas dicots exhibit a ring arrangement.

• Roots: Monocots have a fibrous root system, while dicots predominantly display a taproot system.

• Flower Arrangement: Monocots commonly have petals in multiples of 3, while dicots typically have petals in multiples of 4 or 5.

Importance of Seed Plants

Seed plants are essential for ecosystems, serving as critical sources of food, medicines, and materials among various organisms, underscoring their role in sustaining life on Earth.

Plant Form and Physiology (Chapters 35 and 39)

Definitions

• Herbaceous: Non-woody plants generally characterized by soft stems.

• Woody Plant: Plants that produce hard, lignin-rich stems and branches, contributing to longevity and structural integrity.

• Annual/Biennial/Perennial: Classifications based on lifecycle durations; annuals complete their life cycle in one year, biennials in two, and perennials live for several years.

• Deciduous/Evergreen: Refers to plants that either shed their leaves seasonally (deciduous) or retain their foliage year-round (evergreen).

• Primary/Secondary Growth: Primary growth extends the length of the plant, while secondary growth increases the girth through the development of woody tissues.

• Roots: Structures primarily responsible for anchoring and nutrient absorption; can differ as taproots or fibrous roots.

Plant Body of Angiosperms

The basic structure of angiosperms is composed of roots, stems, and leaves, forming the essential components for survival and reproduction.

Root and Shoot Systems

• Root System: Functions in anchoring the plant and facilitating water/nutrient uptake from the soil.

• Shoot System: Comprises all above-ground organs such as stems and leaves, playing a crucial role in photosynthesis and reproduction.

Plant Tissues

• Meristematic Tissue: Consists of actively dividing cells that contribute to plant growth.

• Permanent Tissue: Consists of specialized, differentiated cells that perform specific functions.

Ground Tissue Function

Ground tissue supports overall plant structure, involved in photosynthesis and storage of nutrients and carbohydrates.

Vascular Tissue Function

This tissue type is vital for transporting water, nutrients, and food throughout the plant; it includes both xylem and phloem.

Dermal Tissue Function

Dermal tissue serves a protective role for the plant, encompassing structures like the epidermis and periderm to guard against environmental threats.

Main Functions of Plant Structures

• Stems: Provide support, facilitate transport of nutrients and water, and may serve storage functions.

• Roots: Anchor the plant in the soil, absorb water and nutrients, and store energy.

• Leaves: Primary site for photosynthesis, facilitating gas exchange, and contributing to transpiration, which cools the plant and aids nutrient uptake.