Biodiversity

Q: What characteristics do green algae and land plants share?

A: Both have cellulose cell walls, chloroplasts with chlorophyll, energy stored as starch, and alternation of generations.

Q: How are green algae adapted to aquatic life?

A: Green algae are supported by water, absorb water and nutrients directly, use swimming gametes/spores, and depend on moist environments for reproduction.

Q: What adaptations allowed plants to move onto land?

A: Plants evolved waxy cuticles, supporting tissues/lignin, air-dispersed spores and pollen, roots, vascular tissue, and reproduction without swimming sperm.

Q: What evidence suggests charophytes are ancestors of land plants?

A: Charophytes share similar DNA, chloroplasts, reproductive traits, and fossil similarities with land plants.

Q: What are bryophytes?

A: Bryophytes are nonvascular plants including mosses, liverworts, and hornworts.

Q: What adaptations helped bryophytes survive on land?

A: Bryophytes evolved waxy cuticles, spongy mats to retain water, protective embryo jackets, and dry spores dispersed by air.

Q: What adaptations distinguish seedless vascular plants?

A: Seedless vascular plants evolved vascular tissue, roots, stems, leaves, stomata, and dominant sporophytes.

Q: Why were seedless vascular plants important ecologically?

A: They formed Earth’s first forests and contributed to coal formation.

Q: What are gymnosperms?

A: Gymnosperms are seed plants such as conifers, cycads, and ginkgoes.

Q: What adaptations do gymnosperms have?

A: Gymnosperms evolved seeds, pollen, cones, wind pollination, and dominant sporophytes.

Q: What are angiosperms?

A: Angiosperms are flowering plants that produce seeds enclosed in fruit.

Q: What major adaptations do angiosperms have?

A: Angiosperms evolved flowers, fruits, double fertilization, and animal pollination strategies.

Q: What is alternation of generations?

A: Alternation of generations is a life cycle alternating between haploid gametophyte (1n) and diploid sporophyte (2n) stages.

Q: Which generation is dominant in bryophytes?

A: The gametophyte generation is dominant in bryophytes.

Q: Which generation is dominant in vascular plants?

A: The sporophyte generation is dominant in vascular plants.

Q: How does reproduction differ between bryophytes and seed plants?

A: Bryophytes require swimming sperm and water for fertilization, while seed plants use pollen and do not require free water.

Q: How is alternation of generations different in gymnosperms and angiosperms?

A: Both have dominant sporophytes, but gymnosperms use cones and naked seeds while angiosperms use flowers and double fertilization.

Q: What is the function of spores?

A: Spores are reproductive cells dispersed by air that grow into gametophytes without fertilization.

Q: What is the function of pollen?

A: Pollen carries the male gametophyte and allows fertilization without water.

Q: What is the function of seeds?

A: Seeds protect embryos, provide stored food, and aid in dispersal and survival.

Q: What are axillary buds?

A: Axillary buds are buds that can develop into branches or flowers.

Q: What are apical meristems?

A: Apical meristems are regions of active cell division at root and shoot tips responsible for plant growth.

Q: What is the function of stomata?

A: Stomata regulate gas exchange and water loss through transpiration.

Q: What is the function of xylem?

A: Xylem transports water and minerals upward from roots to shoots and provides structural support.

Q: What is the function of phloem?

A: Phloem transports sugars and organic nutrients throughout the plant.

Q: What structures make up the male parts of a flower?

A: The stamen is the male structure, and the anther produces pollen.

Q: What structures make up the female parts of a flower?

A: The pistil is the female structure; the stigma collects pollen and the ovary produces eggs.

Q: What are sepals and petals?

A: Sepals and petals are modified leaves that protect and attract pollinators.

Q: What happens during double fertilization?

A: One sperm fertilizes the egg to form a 2n zygote, while another sperm fertilizes the polar nuclei to form endosperm for embryo nutrition.

Q: What is endosperm?

A: Endosperm is the food supply within a seed that nourishes the developing embryo.

Q: What are monocots?

A: Monocots have one seed leaf, flowers in multiples of 3, and parallel veins.

Q: What are dicots?

A: Dicots have two seed leaves, flowers in multiples of 4 or 5, and branching veins.

Q: How are orchids and composites adapted for pollination?

A: They evolved specialized flowers adapted for animal pollination.

Q: How are grasses and trees adapted for pollination?

A: They have small inconspicuous flowers adapted for wind pollination.

Q: What are cohesion forces in water?

A: Cohesion forces allow water molecules to stick together and move as a continuous column.

Q: What are adhesion forces in water?

A: Adhesion forces allow water to stick to surfaces and aid transport through xylem.

Q: What is transpiration?

A: Transpiration is the evaporation of water from leaves that creates an upward pulling force in xylem.

Q: What is xylem sap?

A: Xylem sap is water and dissolved minerals transported upward from roots to shoots.

Q: What is phloem sap?

A: Phloem sap contains sugars and nutrients transported between shoots and roots.

Q: What is the cohesion-tension hypothesis?

A: The cohesion-tension hypothesis explains water movement through xylem using transpiration pull and cohesion between water molecules.

Q: What is apoplastic transport?

A: Apoplastic transport moves water through cell walls and spaces outside plasma membranes.

Q: What is symplastic transport?

A: Symplastic transport moves water through the cytoplasm of connected cells via plasmodesmata.

Q: What is transmembrane transport?

A: Transmembrane transport moves water across plasma membranes from cell to cell.

Q: What is membrane potential?

A: Membrane potential is the electrical charge difference across a cell membrane that drives diffusion, cotransport, and osmosis.

Q: What is water potential?

A: Water potential predicts the direction of water movement from high water potential to low water potential.

Q: What is solute pressure?

A: Solute pressure is always negative and becomes more negative as solute concentration increases.

Q: What is physical pressure?

A: Physical pressure is pressure exerted on a solution and may be positive or negative relative to atmospheric pressure.

Q: What is turgor pressure?

A: Turgor pressure is pressure from the cell wall against the cytoplasm that keeps plants rigid and prevents wilting.

Q: What causes transpiration pull?

A: Negative pressure created by evaporation at the leaf surface pulls water upward through xylem.

Q: What do proton pumps do in plants?

A: Proton pumps create membrane potential and hydrogen ion gradients used for transport.

Q: What are Casparian strips?

A: Casparian strips are waterproof barriers in roots that force water through selective membranes before entering vascular tissue.

Q: What are plasmodesmata?

A: Plasmodesmata are microscopic channels connecting plant cells for direct cytoplasmic transport.

Q: How do stomata open?

A: Light stimulates guard cells to accumulate potassium ions and water, making them turgid and opening stomata.

Q: What are xerophytes?

A: Xerophytes are plants adapted to dry environments, such as cacti.

Q: How do xerophytes reduce water loss?

A: Xerophytes open stomata at night, keep stomata closed during the day, and often perform photosynthesis in stems instead of leaves.