Topic 10 - Learning Objectives Flashcards
- Compare the processes of sporogenesis and gametogenesis in plants including the type of division and the structure in which it occurs. #analyze
Sporogenesis:
- Type of Division: Meiosis
- Structure: Occurs within sporangia, specialized structures found in sporophytes.
- Process: Meiosis produces haploid spores from diploid sporocytes. These spores undergo mitotic divisions to develop into gametophytes.
Gametogenesis:
- Type of Division: Mitosis
- Structure: Occurs within gametangia, specialized structures found in gametophytes.
- Process: Mitotic divisions occur within gametangia to produce gametes (sperm and egg cells). These gametes are typically produced by gametophytes through mitosis.
- Compare homospory and heterospory. #understand
Homospory:
- Production of only one type of spore.
- Example: Most bryophytes and some seedless vascular plants exhibit homospory.
- Develops into bisexual gametophytes that produce both male and female gametes.
Heterospory:
- Production of two types of spores - microspores (male) and megaspores (female).
- Example: Seed plants (gymnosperms and angiosperms) and some seedless vascular plants exhibit heterospory.
- Develops into unisexual gametophytes specialized for producing either male or female gametes.
- Explain how sperm travels to the egg in the four major plant phyla. #understand
- a) Describe mechanisms how self-fertilization can be prevented in plants. #understand
- Physical barriers such as spatial separation of male and female reproductive structures.
- Mechanisms to ensure that pollen from one flower is not transferred to the stigma of the same flower (self-incompatibility).
- b) Compare pollination between gymnosperms and angiosperms. #analyze
- Gymnosperms:
Reliant on wind pollination, where pollen grains are dispersed by the wind to reach female cones. - Angiosperms:
Utilize a variety of pollination mechanisms, including wind, insects, birds, and other animals to transfer pollen from anther to stigma.
- Diagram the embryonic development and structure in flowering plants. #apply
- Embryonic development in flowering plants begins with double fertilization, where one sperm fertilizes the egg to form the zygote, and another sperm fuses with polar nuclei to form endosperm.
- The zygote develops into an embryo consisting of an embryonic axis (root-shoot axis) and one or two cotyledons (seed leaves).
- The embryo is enclosed within the seed, along with the endosperm and protective seed coat.
- Explain fruit development and how it relates to flower structure. #analyze
- Fruit development begins after fertilization, where the ovary wall thickens and matures into the fruit.
- The fruit protects the developing seeds and aids in their dispersal.
- The structure of the fruit is closely related to the structure of the flower from which it develops, with the ovary of the flower becoming the fruit
- Describe the mechanisms of seed dispersal in gymnosperms and angiosperms. #understand
- Gymnosperms:
Seeds are often dispersed by wind, gravity, or animals. Some gymnosperms have specialized structures like wings or fleshy coatings to aid in dispersal. - Angiosperms:
Seeds are dispersed through various mechanisms including wind, water, animals, and explosive mechanisms. Fruits often play a crucial role in seed dispersal by attracting animals or facilitating wind dispersal.
- a) Explain the benefit of seed dispersal. #understand
Seed dispersal allows plants to colonize new habitats, reduces competition among offspring, and increases genetic diversity.
- b) Explain the purpose of seed dormancy and the process of germination. #understand
- Seed dormancy allows seeds to remain inactive until conditions for germination are favorable, preventing premature germination.
- Germination is the process by which a seed embryo resumes growth and develops into a seedling under suitable environmental conditions.
- Compare the developmental stages of plants and animals from zygote to adult. #evaluate
Plants and animals exhibit different developmental patterns, with plants undergoing alternation of generations, including both haploid and diploid stages, while animals typically develop from a zygote to a multicellular embryo through mitotic cell divisions.
- List the three types of plant organs. #understand
- Roots
- Stems
- Leaves
- List the three types of plant tissues. #understand
- Dermal Tissue
- Ground Tissue
- Vascular Tissue
- Describe the location, shape, structure, and function of the seven cell types listed in figure 35.10. #understand
- Explain how the secondary cell wall is deposited by plant cells. #understand
- Secondary cell wall deposition occurs after the primary cell wall is formed and involves the addition of specialized materials, such as lignin and cellulose, to the existing cell wall.
- Secondary cell wall formation is initiated by the differentiation of certain cells, such as xylem and sclerenchyma cells, which require additional structural support.
- Cells deposit lignin and other materials in layers, gradually thickening the cell wall and providing mechanical strength and rigidity to the cell.
- The process of secondary cell wall deposition is regulated by genetic and environmental factors, ensuring proper cell wall development and functionality
- List the major functions of roots, shoots, and leaves. #analyze
- Roots:
Anchor the plant, absorb water and nutrients from the soil, store food reserves, and sometimes aid in vegetative propagation. - Shoots:
Support leaves and reproductive structures, conduct photosynthesis, transport water, nutrients, and hormones between roots and leaves, and provide structural support for the plant. - Leaves:
Main site of photosynthesis, exchange gases with the atmosphere, regulate water loss through transpiration, and sometimes store food reserves.
- Diagram the types of roots and root systems. #understand
- Types of roots include taproots (e.g., in carrots) and fibrous roots (e.g., in grasses).
- Root systems can be categorized into fibrous root systems (network of thin roots of similar diameter) and taproot systems (main vertical root with smaller lateral roots).
- a) Explain how lateral roots develop. #understand
Lateral roots develop from the pericycle, a layer of cells within the primary root, through the process of lateral root initiation, elongation, and emergence.
- Explain primary growth at the root apical meristem. #analyze
- Tissues Produced: The root apical meristem produces primary tissues, including protoderm (gives rise to epidermis), ground meristem (gives rise to ground tissue), and procambium (gives rise to vascular tissue).
- Organs Produced: Primary growth at the root apical meristem results in the formation of primary root tissues and the elongation of the primary root.
- a) Identify what tissues are produced and where. #understand
- The root apical meristem gives rise to three primary tissues: the protoderm, ground meristem, and procambium.
- The protoderm develops into the epidermis, the outermost protective layer of the root.
- The ground meristem differentiates into the ground tissue system, which includes the cortex and the endodermis.
- The procambium differentiates into the vascular tissue system, which includes the primary xylem and primary phloem.
- b) Identify what organs are produced and where. #understand
- The root apical meristem produces the primary root, which extends through the soil and anchors the plant.
- Root hairs, extensions of epidermal cells, also develop from the root’s surface to increase surface area for water and nutrient absorption.
- Describe the process of cell elongation in plant roots and shoots. #analyze
- Cell elongation in plant roots and shoots occurs primarily in the zone of elongation, located just above the root apical meristem or shoot apical meristem.
- In roots, cell elongation is facilitated by the uptake of water into the vacuole, increasing turgor pressure, and stretching the cell wall.
- In shoots, cell elongation is driven by the expansion of cells in response to turgor pressure generated by water uptake and the loosening of cell walls facilitated by enzymes called expansins.
- As cells elongate, they push neighboring cells, causing overall tissue expansion and growth.
- Diagram typical eudicot and monocot root cross sections and label all parts. #understand
- Identify various root adaptations and explain how each benefits the plants who has it. #analyze
- Taproot System: Provides anchorage and allows for deep penetration into soil for access to water and nutrients.
- Fibrous Root System: Increases surface area for water and nutrient absorption, enhancing stability in shallow soils.
- Root Hairs: Increase surface area for absorption of water and minerals.
- Pneumatophores: Found in mangroves, aid in gas exchange in waterlogged soils.
- Contractile Roots: Pull the plant deeper into the soil, aiding in stability and protection against adverse environmental conditions.
- Explain primary growth at the shoot apical meristem. #analyze
- a) Identify what tissues are produced and where. #understand
- The shoot apical meristem produces three primary tissues: dermal, ground, and vascular tissues.
- Dermal tissue gives rise to the epidermis, which protects the shoot surface.
- Ground tissue differentiates into the cortex and pith, providing structural support and storage.
- Vascular tissue differentiates into primary xylem and primary phloem, facilitating water and nutrient transport.
- b) Identify what organs are produced and where. #understand
- The shoot apical meristem produces stems, leaves, and reproductive structures such as flowers.
- Stems provide support and conduct water and nutrients between roots and leaves.
- Leaves perform photosynthesis and gas exchange, contributing to plant growth and metabolism.
- Flowers facilitate sexual reproduction, leading to seed production and dispersal.
- Diagram typical eudicot and monocot shoot cross sections and label all parts. #understand
- Identify various shoot adaptations and explain how each benefits the plants who has it. #analyze
- Tendrils: Assist in climbing for support and access to sunlight.
- Thorns: Provide protection against herbivores and may also aid in water storage.
- Storage Organs: Store water, nutrients, and energy reserves for periods of dormancy or adverse conditions.
- Spines: Reduce water loss by minimizing surface area exposed to sunlight and wind.
- Air Roots: Enhance gas exchange in waterlogged soils or provide additional support in epiphytic plants.
- Explain the growth of a leaf from a leaf primordium. #understand
- A leaf develops from a leaf primordium, a small bump or outgrowth on the plant’s apical meristem.
- Cells within the leaf primordium undergo rapid cell division and differentiation, forming the leaf blade, petiole (stalk), and various leaf tissues.
- As the leaf matures, it expands and adopts its final shape and structure.
- Compare simple and compound leaves. #understand
- Simple Leaves: Consist of a single leaf blade attached to the stem by a petiole.
- Compound Leaves: Comprise multiple leaflets attached to a common petiole.
- Diagram typical leaf cross sections and label all parts. #understand
- Identify various leaf adaptations and explain how each benefits the plants who has it. #analyze
- Succulence: Thick, fleshy leaves store water, enabling plants to survive in arid environments.
- Needles: Reduced surface area minimizes water loss in xeric environments and protects against herbivory.
- Window Leaves: Transparent structures allow light to penetrate to lower leaf layers for photosynthesis in shady environments.
- Tendrils: Aid in climbing for access to sunlight and support.
- Spines: Reduce water loss and deter herbivores.
- Explain how eudicots increase in girth during secondary growth. #understand
- a) Describe the production of secondary tissues by the cambia. #understand
- Vascular cambium produces secondary xylem (wood) towards the center of the stem and secondary phloem towards the bark.
- Cork cambium (phellogen) produces cork cells towards the outside, forming bark.
- Explain how growth rings develop. #understand
- Growth rings form due to variations in secondary xylem production between seasons.
- During favorable growing seasons, large, thin-walled cells are produced, resulting in light-colored early wood.
- In unfavorable conditions, smaller, thicker-walled cells are produced, forming dark-colored late wood.
- Alternating layers of early and late wood produce annual growth rings, which can be used to determine a tree’s age and environmental conditions during its growth.
Sporogenesis
The process by which spores are produced, typically through meiosis, in organisms like plants, fungi, and some protists.
Homospory
The condition where a plant produces only one type of spore, leading to the development of gametophytes that are either male or female.
Heterospory
The condition where a plant produces two distinct types of spores: microspores, which develop into male gametophytes, and megaspores, which develop into female gametophytes.
Gametogenesis
The process of gamete formation, including the production of sperm cells (spermatogenesis) and egg cells (oogenesis).
Direct pollination
Pollination that occurs when pollen is transferred directly from the anther to the stigma of the same flower or to a different flower on the same plant.
Indirect pollination
Pollination that involves the transfer of pollen from the anther to the stigma by a vector such as wind, water, or animals.
Staminate flower
A flower that only contains male reproductive organs (stamens) and lacks female reproductive organs (carpels).
Carpellate flower
A flower that only contains female reproductive organs (carpels) and lacks male reproductive organs (stamens).
Micropyle
A small opening in the outer integument of an ovule through which the pollen tube enters during fertilization.
Double fertilization
A process unique to angiosperms where one sperm cell fertilizes the egg cell to form the zygote, while another sperm cell combines with two polar nuclei to form the triploid endosperm.
Endosperm
Nutritive tissue formed during double fertilization in angiosperms, providing nourishment to the developing embryo.
Zygote
The cell formed by the fusion of two gametes (sperm and egg), which develops into a new organism.
Terminal cell
The cell at the end of a developing structure or organ.
