Ch.29 - Plant Diversity I Flashcards
Plants evolved from a green algae ancestor, but have some important differences, especially relating to the ____________ in their lifecycle.
Plants evolved from a green algae ancestor, but have some important differences, especially relating to the alternation of generations in their lifecycle.
Bryophytes are __________ (non/vascular) plants which have clearly observable _____________ (gametophytes/sporophytes).
Bryophytes are nonvascular plants which have clearly observable gametophytes.
Vascular plants have many adaptations and more visible ___________ (sporo/gametophytes).
Vascular plants have many adaptations and more visible (dominant) sporophytes.
Around ____ million years ago, small plants, fungi, and animals emerged on land. Since colonizing land, plants have diversified into roughly _____ (#) living species.
Around 500 million years ago, small plants, fungi, and animals emerged on land. Since colonizing land, plants have diversified into roughly 290k living species.
T/F: Land plants are defined as having terrestrial ancestors, even though some are now aquatic.
True
Land plants are defined as having terrestrial ancestors, even though some are now aquatic.
T/F: Land plants include photosynthetic protists (algae)
False
Land plants do NOT include photosynthetic protists (algae)
What are some key characteristics of terrestrial plants?
Key characteristics of terrestrial plants:
- Multicellular
- Eukaryotic
- Photosynthetic autotrophs
- Cell walls made of cellulose
- Chloroplasts w chlorophyll a and b
Note that many protists share these traits, incl brown, red, and green algae.
________ are the closest relative to terrestrial plants.
Charophytes (type of green algae) are the closest relative to terrestrial plants.
Plants and Charophyte green algae share which key characteristics?
Plants and Charophyte green algae share key characteristics:
- Rings of cellulose-synthesizing proteins
- Structure of the sperm: flagella present
- Formation of a phragmoplast: group of microtubules that form between daughter nuclei of the dividing cell
Many species of charophytes live in shallow waters. What adaptation allowed plants to survive dry periods on land?
Sporopollenin – durable polymer that prevents zygotes from drying out
Which derived traits of plants are found in the embryophyte kingdom Plantae but not in charophytes?
- Alternation of generations
- Multicellular dep embryos.
- Production of walled spores in sporangia
- Multicellular gametangia
- Apical meristems
Plants also have mycorrhizae–symbiotic associations b/w fungi/plants; cuticle, a waxy covering of the epidermis; and stomata, specialized cells that allow for gas exchange between the outside air and the plant.
Bryophyta (seedless, non-vascular plants) include which three phyla?
Bryophyta (seedless, non-vascular plants) include Hepatophyta (liverworts), Bryophyta (Mosses), and Anthocerophyta (hornworts).
Seedless vascular plants incl wh two phyla?
Seedless vascular plants:
- Phylum Lycophyta (lycophytes)
- Phylum monilophyta (monilophytes)
Vascular seed plants incl gymnosperms and angiosperms. Which phyla are included in gymnosperms? Angiosperms?
Gymnosperms (vascular seed plants):
- ginkgophyta
- cycadophyta
- gnetophyta
- coniferphyta
Angiosperms:
- Anthophyta (flowering plants)
What is meant by alternation of generations?
Lifecycle of all plants alternate between gametophyte (haploid) and sporophyte (diploid) forms; not found in charophytes.
- Gametophyte generation is haploid and produces haploid gametes by mitosis
- Fusion of a sperm and egg gives rise to the diploid sporophyte, wh produces haploid spores by meiosis
- Spores develop into gametophytes
What are sporophytes?
Sporophyte: “spore producing plant”
- diploid zygote grows, dividing by mitosis, produces sporophyte
- Sporophyte undergoes meiosis to produce spores
- Reproductive cells that develop into haploid organisms (the gametophyte)
The diploid zygote grows, dividing by ______ (mitosis/meiosis), to produce a sporophyte. The sporophyte undergoes ______ (mitosis/meiosis) to produce spores.
The diploid zygote grows, dividing by mitosis, to produce a sporophyte. The sporophyte undergoes meiosis to produce spores.
T/F: In seedless plants, both gametophytes and sporophytes are visible, while in flowering (seed) plants only the sporophytes are visible.
True
In seedless plants: both gametophytes and sporophytes are visible, but look very different
In flowering plants: only the sporophytes are visible; gametes are microscopic
Dev of the embryo (fr the zygote) occurs in the tissues of the _______________.
Dev of the embryo (fr the zygote) occurs in the tissues of the female gametophyte.
- Specialized placental transfer cells enhance transfer of nutrients.
- Landplants referred to as embryophytes bc of this derived trait (multicell, dep embryos).
Landplants referred to as embryophytes bc of wh derived trait?
Multicellular, dependent embryos
The sporophyte produces spores in organs called _________.
The sporophyte produces spores in organs called sporangia.
Diploid cells called _________ undergo meiosis to generate haploid spores.
Diploid cells called sporocytes undergo meiosis to generate haploid spores.
________ (hap/diploid) cells called sporocytes undergo meiosis to generate ________ (hap/diploid) spores.
Diploid cells called sporocytes undergo meiosis to generate haploid spores.
What advantage does sporopollenin offer?
Spore walls contain sporopollenin, which makes them resistant to harsh environments
Summarize the diffs b/w spores, sporangia, and sporocytes
Spores – haploid reproductive cells
Sporangia – multi-cellular organs that produce spores
Sporocytes – diploid cells that undergo meiosis to produce spores
Archegonia are female gametangia while antheridia are male gametangia. Summarize the diffs.
Archegonia – female gametangia
- pear-shaped organ that produces a single egg
Antheridia – male gametangia
- Produce sperm, many wh have flagella to swim to archegonium.
What are apical meristems?
Apical meristems
- Found at the tips of roots and shoots
- Regions where cell division occurs
- Differentiation of cells leads to specialized tissues
Define the following terms and their relationship to each other: sporophyte, sporangia, sporocytes, spores.
Spores – haploid reproductive cells
Sporangia – multi-cellular organs that produce spores
Sporocytes – diploid cells that undergo meiosis to produce spores
Sporophyte - diploid, dominant form of vascular plants
The gametophyte generation is haploid and produces haploid gametes by mitosis. Fusion of a sperm/egg gives rise to diploid sporophyte, wh produces haploid spores by meiosis. Spores dev into gametophytes.
Define the following terms and their relationship to each other: gametophyte, gametangia, archegonia, antheridia.
Gametangia are organs found in gametophytes where the production of gametes occurs.
- Archegonia - female gametangia; produces ONE egg.
- Antheridia - male gametangia; produces many sperm.
The gametophyte generation is haploid and produces haploid gametes by mitosis. Fusion of a sperm/egg gives rise to diploid sporophyte, wh produces haploid spores by meiosis. Spores dev into gametophytes.
T/F: Bryophyte gametophytes are larger and longer-lived than sporophytes.
True
In bryophytes, gametophyte is the dominant stage.
Spores grow into gametophytes in damp environments (soil, tree bark)
________ are one-cell thick filaments that help with water absorption
________ are structures that produce gametes
Protonema – one-cell thick filaments that help with water absorption
Gametophore – structure that produces gametes
Bryophyte sporophytes grow out of __________, and are the smallest and simplest sporophytes of all extant plant groups
Bryophyte sporophytes grow out of archegonia, and are the smallest and simplest sporophytes of all extant plant groups
A sporophyte consists of a foot, a ____ (stalk), and a sporangium, also called a _______, wh discharges spores through a ________.
A sporophyte consists of a foot, a seta (stalk), and a sporangium, also called a capsule, which discharges spores through a peristome.
Label the attached diagram for plant taxonomy.
Seedless vascular plants are mostly found in ______ (arid/damp) environments.
Seedless vascular plants are mostly found in damp environments.
- Recall: lycophytes and monilophytes. Need damp environ bc sperm must SWIM to eggs in archegonia of another gametophyte.
Describe the two types of leaves.
Sporophylls - modified leaves bearing sporangia
- Microphylls - leaves w a single vein
- Megaphylls - leaves w a highly branched vascular system
T/F: most seedless vascular plants are heterosporous.
False
Most seedless vascular plants are homosporous.
- Produce ONE type of spore.
- Produce bisexual gametophyte that produces both eggs and sperm.
T/F: some seedless vascular plants are heterosporous.
True
SOME seedless vascular plants are heterosporous. (ALL seed plants are heterosporous)
Heterosporous: TWO types of sporangia → produce two type of spores:
- Megasporangia produce megaspores that dev into female gametophytes, wh will produce eggs.
- Microsporangia produce microspores that dev into male gametophytes, wh will produce sperm.
What is the diff b/w mega and microsporangia?
Megasporangia produce megaspores that dev into female gametophytes, wh will produce eggs.
Microsporangia produce microspores that dev into male gametophytes, wh will produce sperm.
Fern gametophytes are __________.
- produced from haploid gametes
- free-living, multicellular organisms
- part of the asexual life cycle
- found on the underside of fern leaves (fronds)
- photosynthetic diploid organisms
Fern gametophytes are __________.
- produced from haploid gametes
- free-living, multicellular organisms
- part of the asexual life cycle
- found on the underside of fern leaves (fronds)
- photosynthetic diploid organisms
Ferns (monilophytes; non-vascular) produce small heart-shaped gametophytes that sustain themselves by psynth and produce haploid gametes.
Most fern species are homosporous -> devs into bisexual psynthc gametophyte -> EACH gametophyte devs antheridia AND archegonia.
Gametophytes are haploid.
Gametophytes produce gametes.
Gametophytes are involved in sexual reproduction.
The underside of the leaf (frond) is where sori are found.
