Topic 9 - Learning Objectives Flashcards
- Explain the evidence of shared ancestry between the plants and green algae. #analyze
- Morphologically, both groups possess chlorophylls a and b, as well as similar photosynthetic pigments such as carotenoids.
- They also share cell wall composition, with cellulose being a major component. Additionally, the reproductive structures of green algae and plants, such as the presence of multicellular sporangia and gametangia, indicate a common ancestry.
- Molecular evidence, including DNA sequencing and phylogenetic analyses, further support the close relationship between plants and green algae by revealing similarities in genetic sequences and evolutionary relationships.
- Describe the defining characteristics of plants. #remember
Plants are characterized by several defining features, including:
- Presence of chlorophylls a and b for photosynthesis
- Multicellular, eukaryotic structure
- Cell walls composed of cellulose
- Alternation of generations life cycle with a dominant sporophyte phase
- Embryonic development protected within specialized structures (embryophytes)
- Ability to synthesize complex organic molecules from inorganic substances through photosynthesis
- Illustrate the typical plant life cycle. #understand
Involves alternating between a haploid gametophyte phase and a diploid sporophyte phase. It consists of the following stages:
- Sporophyte generation produces haploid spores through meiosis.
- Spores germinate and develop into multicellular haploid gametophytes.
- Gametophytes produce gametes (sperm and egg cells) through mitosis.
- Fertilization occurs when sperm cells fertilize egg cells, forming a diploid zygote.
- The zygote develops into a multicellular diploid sporophyte through mitosis, completing the cycle.
- a) Identify the major differences between the life cycles of the four major plant phyla. #evaluate
Major differences between the life cycles of the four major plant phyla include variations in the dominance of the gametophyte or sporophyte phase, presence or absence of vascular tissue, and method of reproduction (e.g., spores or seeds).
- Compare the basic gametophyte and sporophyte body plans of the four major plant phyla. #analyze
The basic gametophyte and sporophyte body plans of the four major plant phyla (Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms) exhibit variations in size, complexity, and reproductive structures.
- a) Identify characters that are shared between related phyla. #analyze
Shared characters between related phyla may include similar reproductive structures (e.g., archegonia, antheridia), alternation of generations life cycle, and similar cellular structures.
- b) Classify plants into clades based on specific characteristics provided in a photo or written description. #evaluate
Classification of plants into clades based on specific characteristics involves grouping them according to shared derived traits, such as presence of seeds, vascular tissue, or flowers.
- c) Compare the processes of gametogenesis and sporogenesis in each. #understand
Gametogenesis and sporogenesis refer to the processes of gamete and spore formation, respectively, which may vary in timing, location, and cellular processes among different plant phyla.
- d) Identify the gametangia and sporangia of each. #understand
Gametangia are structures that produce gametes (e.g., archegonia in females, antheridia in males), while sporangia produce spores (e.g., sporangia in sporophytes of ferns, cones in gymnosperms).
- Construct a phylogenetic tree of the four plant phyla discussed in this course. #create
Construction of a phylogenetic tree of the four plant phyla involves organizing them based on shared evolutionary relationships and derived characteristics.
- a) Identify the best outgroup for this tree. #analyze
The best outgroup for this tree may include green algae or other non-plant organisms to root the tree and provide a reference point for comparing evolutionary changes.
- b) Explain the trend in the evolution of true organs. #understand
The trend in the evolution of true organs involves the development of specialized structures for specific functions, such as roots for anchorage and absorption, leaves for photosynthesis, and flowers for reproduction.
- c) Explain the trend in the evolution of the dominant generation. #understand
The trend in the evolution of the dominant generation refers to shifts in dominance between the haploid gametophyte phase and the diploid sporophyte phase, with land plants exhibiting a trend toward sporophyte dominance.
- d) Explain the trend in the evolution of the dependency on water. #understand
The trend in the evolution of dependency on water involves adaptations allowing plants to reduce reliance on water for reproduction, such as the development of seeds and pollen for dispersal in terrestrial environments.
- e) Explain the trend in the evolution of the size and complexity of gametophyte and sporophyte generations. #understand
The trend in the evolution of the size and complexity of gametophyte and sporophyte generations varies among plant groups, with some exhibiting a reduction in gametophyte size and complexity and an increase in sporophyte dominance.
- Describe the adaptations that allowed plants to move further onto land. #evaluate
Adaptations that allowed plants to move further onto land include the development of specialized structures for water and nutrient absorption (roots), structural support (stems), and gas exchange (leaves). Additionally, the evolution of vascular tissue facilitated the transport of water, nutrients, and photosynthetic products throughout the plant.
- Explain the evolutionary impact of heterospory in the plants. #evaluate
Heterospory in plants has evolutionary impacts such as the production of two types of spores (microspores and megaspores), leading to the development of separate male and female gametophytes. This adaptation enhances reproductive efficiency and allows for greater specialization in sexual reproduction.
- Describe the spore-producing structures in typical gymnosperms. #understand
Spore-producing structures in typical gymnosperms include cones or strobili, which bear reproductive structures called sporophylls. Male cones produce pollen grains containing male gametophytes, while female cones produce ovules containing female gametophytes.
- Illustrate the ovule and the seed and compare the structures in each. #understand
The ovule and seed are structures involved in the reproductive cycle of seed plants. Both structures consist of an integument surrounding a megasporangium, with the ovule containing a female gametophyte and the seed containing a developing embryo and nutritive tissues. Gymnosperm seeds are not enclosed within a fruit, while angiosperm seeds are enclosed within a fruit.
- a) Compare the ovules/seeds of gymnosperms and angiosperms. #analyze
Ovules/seeds of gymnosperms are typically exposed on the surface of cones, while those of angiosperms are enclosed within ovaries and develop into fruits.
- Identify all four whorls of a perfect/complete flower. #understand
The four whorls of a perfect/complete flower include sepals (calyx), petals (corolla), stamens (androecium), and carpels (gynoecium).
- a) Describe the spore-producing structures in typical angiosperms. #understand
Spore-producing structures in typical angiosperms include stamens, which produce pollen grains containing male gametophytes, and carpels, which contain ovules with female gametophytes.
- Compare the basic characteristics of monocots and eudicots. #analyze
Monocots:
- One Cotyledon
- Parallel Venation in their leaves
- Fibrous Root Systems
- Lack Vascular Cambium (Scattered vascular bundles)
- Floral organs multiple of 3
- Scutellum
- Single furrow or pore (Pollen grain)
Eudicots:
- Two Cotyledon
- Net-like venation in their leaves
- Taproot Systems
- Vascular Cambium (ring-like pattern vascular bundle)
- Floral organs multiples of four or five
- No Scutellum
- Three furrows or pores
Meristem
A region of actively dividing cells in plants, responsible for growth and development throughout the plant’s life.
Haplodiplontic
A life cycle characteristic of plants in which both haploid (gametophyte) and diploid (sporophyte) stages are multicellular and distinct.
Sporophyll
A leaf or leaf-like structure that bears sporangia, where spores are produced.
Sporophyte
The diploid, spore-producing phase in the life cycle of plants, typically dominant in vascular plants and producing haploid spores through meiosis.
Sporocyte
A cell that undergoes meiosis to produce spores.
Spore
A reproductive cell capable of developing into a new organism without the need for fusion with another cell, often dispersed by wind, water, or animals.
Gametophyte
The haploid, gamete-producing phase in the life cycle of plants, typically small and independent in non-vascular plants but reduced in vascular plants.
Thallus
The body of a plant or alga that lacks true stems, roots, or leaves, often flattened and undifferentiated.
Gametophore
A specialized structure in some plants that bears gametangia (structures that produce gametes).
Gametangium
A structure that produces and shelters gametes (sperm or egg cells).
