Plants Pt1 Flashcards
(46 cards)
Why are plants important? Waht are the 5 things they contribute?
- Provide food and habitats for every living thing
- Diversity impact animals: Flora diversity ↑ = Animal diversity ↑
- Interact with many organisms (decomposition, animal, nutrient cycles, sun CO2)
- Vital in water, carbon, and nutrient cycles
- Horticulture and tourism Industries
What are the types of cells for sporophytes vs gametophytes? (e.g. diploid or haploid, mitosis vs meiosis)
Gametophytes - haploids that create gametes through mitosis
Sporophytes - diploids that produces spores through meiosis
Four main planet kingdom groups and explain them:
Bryophytes (mosses: liverworts and hornworts) - nonvascular plants but not monophyletic
Pteridophytes (ferns) - vascular plant (monilophytes)
Gymnosperms (naked seeds; pine cones and ginkgo seeds) - vascular plant; seeds not enclosed in chambers
Angiosperms (covered seeds; flowers like pohutukawa, passion fruit, wood rose, and flying duck orchid) - vascular plant; seeds develop inside chambers originating within flowers
main charcteristics of NZ flora:
Divaricating shrubs: branching patterns to create dense and tabled network of stems (hard for herbivores to eat - coevolution?)
Large alpine flowers: harsh for too small flowers, more visible for pollinators (mainly white)
Small flowers: many pollinators are moths, native bees, and crawling insects (not reliant on sight) use mainly scent.
what is a plant archegonia (female)?
pear shaped organ that produces single nonmotile egg retained in the bulbous part.
What is the antheridia (male)?
produce sperm and release them into hte environment. (sperm may have flagella and swim through water)
Apical Meristems:
what is the cuticle in plants?
a protective epidermis covering consisting of wax and other polymers that acts as waterproofing and protection from microbial attacks
What is macroalgae?
photosynthetic, mulitcellular, cells contain chloroplasts, chlorophyll, and cell walls, major parts of coastal ecosystems, blue carbon, and produce most oxygen in biosphere
Waht are chloroplasts, what do they do for the plant, and whcih macroalgae are they found in?
Chloroplasts: organelles found in plants and photosynthetic algae
Have their own genomes, responsible for photosynthesis, perceived as green as they absorb blue and red light (reflect green)
Main groups ⇒ Glaucophytes, red algae, green algae (contain primary chloroplasts that arose from one green algal lineage
Explain endosymbiosis theory and how it relates to certain organelles:
Primary endosymbiosis - unicellular heterotrophic protists engulfing free-living photosynthetic cyanobacteria and retaining it instead of digesting in food vacuoles, endosymbionts then turned into organelles bound by two membranes, and transmitted vertically to subsequent generations.
Chloroplasts likely started as free-living cyanobacteria (part of protist group)
What is brown algae (# of species, what does it form, what chlorophyll pigments does it use?)
and what are its commercial usages?
2,500 known species
Largest and most complex of all algae, all multicellular and live in marine environments exclusively
Most have alternation of generations
Form kelp forests (food source and habitats for other organisms). Khaki brown due to chlorophyll A and C, and green pigments (fucoxanthin - brown pigment)
Commercial usage: alginic acid from cell walls extracted to make thickeners (ice cream, soups, Kombu, cosmetics, gaviscon, and other pharmaceuticals)
What are kelp forests? what is destroying them?
mostly found in coastal zones growing on rocky substrates. Provide habitats, food, and structure for other coastal species (e.g. fish and other seaweeds). Some reach up to 200ft
Urchin Barrens - area that once were kelp forests but transitioned to barren due to overpopulation and grazing from adult urchins. Transition defined by phase shift (where a stable community state is shifted to another)
Causes a decrease in biodiversity as there’s no kep thus no additional habitats for other species and no primary production for juvenile urchins to survive (urchins must be controlled by predators to have a healthy ecosystem)
Caused by change in trophic cascade often due to anthropogenic reasons - predators are reduced or removed from an environment which changes trophic levels.
What is red algae (where is it found, what chlorophyll pigments does it use?)
and what are its commercial uses?
6,000 known species
Most are multicellular, found in warm tropical waters
Most have alternation of generations and reproduce through water currents
Important to building and maintaining coral reefs
Cells coated in agar or carrageenan
Red pigments from phycoerythrin and chlorophyll A and D
Commercial uses: thickening agent (carrageenan and agar) for jellies, Bangiaceae algae family eaten as nori (but demand now outweighs supply), Karengo (grown on rocks in high tide and eaten - must be regulated)
What is green algae (pigments, number of known species, wehre its found)
What are its commercial uses?
7,000 known species
Found in colonies as unicellular and multicellular
Found in freshwater and saltwater (and even in wet soils)
Main source of food for aquatic organisms, and closely related to land plants
Pigment is bright green (chlorophyll A & B) and contain Beta-carotene
Commercial Uses: cosmetics and skincare, B-carotene from extraction, used medically to treat disease like covid and cancer
What are the challenges to transition from water to land? What are the solutions created for this?
Desiccation - Waxy cuticles
Requires structural support - cell walls with lignin
UV radiation - protective flavonoids (pigments) that absorb UV
Gametes must rely on currents to disperse - adaptations to attract pollinators and use rainwater triggers for gametes to release
Dispersal issues (cannot solely rely on currents to disperse) - dispersal adaptations to attract frugivores and have lighter seeds like spores
What are the benefits of marine to terrestrial transition?
More sunlight on land than in water
CO2 diffuses faster and more abundant in air than water
Initially no animals to eat them (only temporary)
What is the evidence that Green algae is the ancestor to all land plants?
Same gene pigments (chlorophyll A and B) in chloroplasts,
same flagellated sperm cells,
requires water to complete reproduction,
common alternation of generations, same synthesis cellulose,
fossils record green algae about 850 mya, and molecular systematics
cellular morphology show both are closely related
What are bryophytes? What is their dominant life stage?
Bryophytes - nonvascular and absorb nutrient and water through nutrients like leaves (cell to cell transport) - most diverse
Lifecycle = (dominant is gametophyte) gametophyte → gametes → sporophyte → spores → gametophyte
What are liverworts?
nonvascular land plants with a gametophyte-dominant life cycle that carry only a single set of genetic information.
Explain the bryophyte sporophyte stage and the stomata:
Sporophytes made of elongated seta and capsule containing sporophytes undergo meiosis to give haploid spores
Have Stomata (and cuticles) - waxy cuticle coating on leaf and stem surfaces as spores that allow gas exchange. Help protect reproductive system (gametangia), spores (sporopollenin), and the embryo (feed on mother plant)
Explain liverwort reproduction and dispersal:
Differ from spore dispersal
Asexual reproduction through gemmae cups (use water that hits the cupped tissue that breaks off and starts growing as broken bits into a new plant
Sexual reproduction - gametongia maybe on some
What are hornworts?
Smallest group, large pencil-like sporangia (thus the name ‘horn’)
what is xylem and what are its characteristics?
xylem - part of vascular system
Thick cell walls made of lignan
Water and minerals
Root to shot (transpiration stream0
No end to walls between cells
What is phloem and what are its characteristics?
phloem - vascular tissue that conducts sugars from source to sink
Thin cell walls (cellulose)
Sucrose and amino acids (+ water) - very thick
2-way flower (source to sink) - translocation of nutrient transport
End wall between cells with perforations (sieve plate)
