Plant Diversity
Plant Diversity + Phylogeny Final Exam Flashcards
Core Plant Evolution
Q: What are the closest living relatives of plants?
A: Charophyte green algae (especially Zygnematophyceae).
Q: Around when did plants originate from green algae?
A: About 470 million years ago.
Q: What major adaptation allowed plants to colonize land?
A: Cuticle, stomata, alternation of generations, spores with sporopollenin, and apical meristems.
Q: What is a cuticle?
A: A waxy waterproof layer that prevents water loss and protects against microbes.
Q: What do stomata do?
A: Allow gas exchange (CO₂/O₂) and regulate water loss.
Q: Why can stomata close?
A: To prevent excessive water loss in hot, dry conditions.
Alternation of Generations
Q: What is alternation of generations?
A: A plant life cycle alternating between multicellular haploid gametophyte and multicellular diploid sporophyte generations.
Q: Which generation produces gametes?
A: Gametophyte.
Q: Which generation produces spores?
A: Sporophyte.
Q: What process produces spores?
A: Meiosis.
Q: What process produces gametes in plants?
A: Mitosis.
Q: What are sporangia?
A: Multicellular organs in sporophytes that produce spores.
Q: What is sporopollenin?
A: A protective coating on spores that resists harsh environments and desiccation.
Plant Groups
Nonvascular Plants (Bryophytes)
Q: What are bryophytes?
A: Nonvascular plants including liverworts, mosses, and hornworts.
Q: Why are bryophytes usually small?
A: They lack vascular/support tissue.
Q: Why do bryophytes live in damp environments?
A: They require water for sperm movement/fertilization.
Seedless Vascular Plants
Q: What are the two major seedless vascular plant groups?
A: Lycophytes and monilophytes (ferns).
Q: What evolutionary novelty allowed vascular plants to grow taller?
A: Vascular tissue.
Q: What are the two vascular tissues?
A: Xylem and phloem.
Q: What does xylem transport?
A: Water and minerals.
Q: What does phloem transport?
A: Sugars, amino acids, and organic products.
Q: Why is vascular tissue advantageous?
A: Allows tall growth, better sunlight access, and farther spore dispersal.
Q: What do roots do?
A: Absorb water/nutrients and anchor the plant.
Q: What is the primary photosynthetic organ in vascular plants?
A: Leaves.
Seed Plants
Q: What is a seed?
A: An embryo packaged with nutrients inside a protective coat.
Q: What are the two seed plant groups?
A: Gymnosperms and angiosperms.
Gymnosperms
Q: What does “gymnosperm” mean?
A: Naked seed plant.
Q: Are gymnosperm seeds enclosed?
A: No.
Q: Most gymnosperms are what type of plants?
A: Conifers.
Q: What structure contains gymnosperm sporangia?
A: Cones.
Angiosperms
Q: What are angiosperms?
A: Flowering plants.
Q: What are the two major angiosperm innovations?
A: Flowers and fruits.
Q: What is the function of flowers?
A: Sexual reproduction.
Q: What are the four floral organs?
A: Sepals, petals, stamens, carpels.
Q: Which floral organs are fertile?
A: Stamens and carpels.
Q: What do stamens produce?
A: Microspores/pollen.
Q: What does the ovule become after fertilization?
A: A seed.
Q: What does the ovary become after fertilization?
A: Fruit.
Q: Why are angiosperms more diverse than gymnosperms?
A: Animal pollination increases genetic diversity and spread.
Monocots vs Eudicots
Q: Which plants have true secondary growth?
A: Gymnosperms and eudicots.
Q: Why don’t monocots have true secondary growth?
A: They lack vascular cambium.
Q: What causes primary growth?
A: Apical meristems.
Q: What causes secondary growth?
A: Vascular cambium.
Q: What is primary growth?
A: Increase in plant length.
Q: What is secondary growth?
A: Increase in plant width.
Lab Techniques
Q: What color indicates starch/photosynthesis in the iodine test?
A: Blue-black.
Q: Why is ethanol used in the photosynthesis test?
A: To remove chlorophyll from the leaf.
Q: How do you test for a cuticle?
A: Water beads on the leaf surface.
Q: How are stomata observed?
A: Nail polish + tape peel under microscope.
Q: What indicates vascular tissue?
A: Ability to grow tall/defy gravity and visible vascular bundles.
Phylogeny Basics
Q: What is a phylogeny?
A: A hypothesis of evolutionary relationships among organisms.
Q: What does a node represent on a phylogenetic tree?
A: A speciation event/shared common ancestor.
Q: What are sister taxa?
A: Two groups sharing an immediate common ancestor.
Q: What is a clade?
A: A common ancestor and all its descendants.
Q: What is a polytomy?
A: A node leading to more than two species.
Q: Does tip order on a phylogeny matter?
A: No — only the nodes determine relationships.
Phylogeny Vocabulary
Q: What is an outgroup?
A: A reference group used to identify ancestral traits.
Q: What is an ancestral trait?
A: Trait shared with the common ancestor.
Q: What is a derived trait?
A: A new trait different from the ancestor.
Q: What is a synapomorphy?
A: A shared derived trait.
Q: In character tables, what does 0 mean?
A: Ancestral version of the trait.
Q: In character tables, what does 1 mean?
A: Derived version of the trait.
Q: What is maximum parsimony?
A: The simplest phylogenetic tree is most likely correct.
Q: What are analogous traits?
A: Similar-function traits with different evolutionary origins.
Molecular Phylogeny
Q: Why do closely related species have similar DNA?
A: Shared ancestry.
Q: What do molecular phylogenies compare?
A: DNA sequence similarities/differences.
Q: Why do scientists combine morphological and molecular data?
A: To build more accurate phylogenies.