deck_1244966 Flashcards
Kingdom Fungi
- Heterotrophic 1. Decomposers (saprobes) 2. Parasites/pathogens (of plants and animals) 3. Mutualists 4. Predaceous (few species)- Chitin (carbohydrate) based cell wall- Mostly multicellular + Yeast is the only exception.- Possess hyphae + Septate or coenocytic- Thallus/micellium + Body of hyphae- May possess haustoria + Specialized hyphae designed for predaceon.
Fungal disease examples
- Black stem rust- Ergots (lysergic acid, or LSD) on rye- Pink ear rot on corn
Examples of mutualistic fungi
- Lichens- Mycorrhizae
Predaceous fungi have adapted ___ for catching prey.
Haustoria
Haustorium
Specialized hypha that inserts itself inside of a host cell (plant/animal) to absorb it from within.
Septate hyphae
Contain septa (singular “septum”) that form cross-walls, separating the individual cells within the the hypha. Septa contain pores that allow organelles to move between compartments.
Coenocytic hyphae
Non-septate hyphae. Nuclei float around freely with the hypha. These hyphae are one large cell.
Mycelium/thallus
A mass of individual hyphae composing the body of the fungus. - Used in feeding. - If fruiting body is not visible, mycelia may still stretch for vast distances underground.
Asexual reproduction in fungi
- Mycelium (n) forms spore-producing structures called sporangia.2. Sporangia releases spores into the environment.3. Spores attach to a food source and germinate, developing their own mycelium.- Asexual reproduction occurs when food is scarce.- Spores may lay dormant and not germinate until food is available.
Sexual reproduction in fungi
- Mycelium (n) of two compatible (+/-) attract one another through the release of pheromones and form side branches to connect.- The hyphae touch and their cytoplasms fuse, engaging in plasmogany.- This area where both hyphae meet becomes its own heterokaryotic cell (n+n).- Karyogamy occurs when the nuclei pair up and fuse together, causing the cell to become a zygote (2n). This is when fertilization is occurring.- Zygote undergoes meiosis to form (n) cells that will develop into sporangia.
Plasmogany
Fusion of cytoplasm - From (n) to (n+n)
Karyogamy
Fusion of nuclei - From (n+n) to (2n) - Also referred to as “fertilization.”
Heterokaryotic hyphae
Possess 2 or more genetically different nuclei resulting from the fusion of hyphae. + Dikaryotic hyphae are a subtype of heterokaryotic hyphae.
Dikaryotic hyphae
Posses exactly 2 nuclei in each cell.
Today’s fungi evolved from ocean dwelling ___ which possessed ___.
Chytrids, flagella
Fungi Phylums
- Chytridiomycota- Zygomycota- Ascomycota- Basidiomycota- Deuteromycota
Phylum Chytridiomycota
“Chytrids” - Aquatic, water mold fungus - Flagellated spores, unique to this phylum - Most primitive fungi - Saprobes or parasitic
Phylum Zygomycota
- Mostly terrestrial + Soil or decaying material- Spores dispersed by air- Mostly coenocytic hyphae- Possess zygosporangium- E.g., Rhizopous (black bread mold) + Zygosporangium is the black portion + Mycelia is the white portion
Zygosporangium
Fruiting body of zygomycota + (n+n)
Zygomycota life cycle
Same as general fungus life cycle, but the zygote in sexual reproduction is referred to as a “zygosporangium” (n+n) following plasmogamy, and becomes a zygote, called a “zygospore” (2n), following karyogamy.- Can determine if fungus was produced asexually or sexually based on if it came from mycelium or a zygosporangium.
Gametangia
Haploid cells from genetically different mycelia after meeting one another but prior to plasmogany.
Phylum Ascomycota
“Sac fungi”- Most diverse group + Marine, freshwater, and terrestrial- Saprobes or parasites- Symbiotic- Include unicellular fungi (yeasts) to very large fungi- Spores dispersed by air- Septate hyphae- E.g., Aspergillus (in peanuts, toxic), Saccharomyces (yeast), Penicillum, ergots (lysergic acid, or LSD) on rye, morels and truffles + Used to make cheese, bread, and wine.
Ascomycota life cycle (asexual)
- Conidiophore releases conidia (spores)- Conidia germinate and develop into mycelia, which then become conidiophores. + Conidiophore with conidia looks like dreadlocks! Only referred to as conidia(phores) in asexual reproduction.
Ascomycota life cycle (sexual)
- One organism’s hyphae will form an “ascogonium” and a genetically different organism will form an “antheridium.”- These structures meet and undergo plasmogamy when the antheridium (now n) deposits its nuclei into the ascogonium (now n+n).- The now (n+n) and (n) hyphae form the “ascocarp,” or fruiting body.- (n+n) Asci (singular “ascus”) will form on the tips of the hyphae of the ascocarp.- Only the ascus undergoes karyogamy to become 2n, while the rest of the hyphae remains (n+n).- Ascus undergoes meiosis to form 4 (n) “ascospores”, which undergo mitosis for a total of 8 ascospores within the ascus.- The ascus releases the ascospores into the atmosphere.- Germination occurs and mycelium develop.Only cells facing the inside of the ascocarp develop an ascus.
Phylum Basidiomycota
“Club fungi”- Major decomposers of wood (lignin)- Septate hyphae- Terrestrial- World’s largest organism- Only reproduce sexually- May smell bad to attract flies that distribute their spores- E.g., mushrooms, toadstools, shelf fungi, puffballs and rusts
Basidiomycota life cycle
- Compatible (n) mycelia meet and undergo plasmogamy.- (n+n) mycelium forms between them, and develops into a “basidiocarp” (fruiting body). The entire fruiting body is (n+n).- Basidiocarp develops “basidia,” similar to the ascus, which is (n+n) until it undergoes karyogamy.- After karyogamy, which only occurs in the (2n) basidium, they undergo meiosis to create 4 basidiospores.- Basidiospores attach externally to the basidium until they are ready to be released (forms a club shape).- After release, spores are able to germinate.
Phylum Deuteromycota
“Imperfect fungi”- No known sexual reproduction (“imperfect” for this reason)- Reproduce asexually through conidiospores- E.g., certain molds, ringworm, predatory fungus (nematode-eater!)
Lichen
Organism produced by a symbiotic relationship between algae/cyanobacteria and fungus (asco/basidio). - Fungus receives sugars from photosynthesis. - Algae receives moisture from hyphae.
Mycorrhizae
Mutualistic relationship between roots and fungi (zygo/asco/basidio). Tends to increase plant growth.- Ectomycorrhizae or endomycorrhizae - Fungus obtains sugars from photosynthesis. - Roots receive water and minerals from hyphae.
Ectomycorrhizae
Fungus wraps around the outside of the root.
Endomycorrhizae
Hyphae penetrate the cell walls of the root.
Commercial use of fungi
Food: Mushrooms, truffles morels, etc.Yeasts: Fermentation of wine, beer, and raising of bread.Antibiotic production: Penicillin from penicillum
Fungi and health
Most fungi are opportunistic and can cause health problems.- Grows in human tissues, especially the lungs + Histoplasmosis- Causes allergies + Aspergillus- Produces mycotoxins - Aspergillus is peanuts and cereals
Histoplasmosis
Condition of having fungus in the lungs, most common in spelunkers due to exposure to bat feces.
Exoenzymes
Used by fungus to break down food into smaller molecules that can then be absorbed.
Predecessor of plants
Phylum Chlorophyta, Class Charophycea”Green algae” + E.g., spirogya- Unicellular, colonial or multicellular- Chlorophyll A & B- Chloroplasts- Cell wall: cellulose and pectin- E.g., Chlamydomonas (unicellular), Volvox (colonial), and Ulva (multicellular)
Shared characteristics between charophycea and land plants
- Intracellular structures + Rosette cellulose-synthesizing protein complex + Peroxisome enzymes + Sporopollenin- Structure of flagellated sperm
Kingdom Plantae
- Multicellular- Photosynthetic autotrophs + Chlorophylls A & B- Monophyletic + One common ancestor for all species- Cell wall: cellulose-based- Reproduce by alternation of generations + Gametophyte and sporophyte- Apical meristems + Allow for tips of roots and shoots grow by acting as stem cells- Starch storage- Gamete evolution + Mostly oogamy but can also use isogamy and anisogamy
Evolution of land plants
- Land colonization began 400 million years ago.- Likely ancestors were green algae.- New issues for land plants and their adaptations: a. Obtaining water - Root system b. Transporting water and nutrients - Conduction tissue c. Water loss due to increased temperatures - Cuticle: wax surface d. Gas exchange - Stomata e. Gravity - Support tissue + E.g., wood f. Reproduction in dry, terrestrial environments and alternation of generations - Gametes protected within gametangia
Bryophytes
“Non-vascular plants”- Lack vascular tissue- Unisexual gametophyte is dominant and sporophyte is ephemeral (short-lived) and dependent on gametophyte.- Most have cuticle and stomata on their leaf-like structures + Hepatophyta does not!- Flagellated sperm cells + Dependent on water for fertilization- Posses rhizoids but no true roots- Small due to lack of vascular tissue- Usually in moist environments- Classification of bryophytes + Phylum Bryophyta + Phylum Hepatophyta + Phylum Anthocerophyta
Phylum Bryophyta
“Mosses”- Most advanced bryophytes- Possess conducting cells- Possess rhizoids- Possess protonemata + Chain-like thread of cells that develops into the gametophyte- Possess cuticle and stomata- E.g, Sphagnum moss
Rhizoids/rhizome
Used to anchor primitive plants into place. Not used for water absorption.
Cuticle
Coating of waxy lipids that retards water loss.
Stomata
Small closable openings in leaves and stems that are used to regulate oxygen exchange.
Gametangia
Multicellular organs that enclose plant gametes and prevent them from drying out.
Bryophyta life cycle
- Spores are either male or female. They germinate and form “protonemata.”- The protonemata forms a bud that develops into a “gametophore.”- At the tip, the male gametophore will develop “antheridia” that produce sperm, and the female will develop “anrchegonia” which hold a single egg within each of them. This entire structure is called either the male or female “gametophyte.”- Rain causes sperm to splash out of the antheridium and into the archegonium.- Fertilization occurs within the archegonium.- Zygote (2n) develops into an embryo. It stays inside of the archegonium until emerging as a young sporophyte.- After emerging, the sporophyte develops a capsule (sporangium). The sporangium contains “peristome” which control spore release.- Sporangium releases spores into the environment.
Phylum Hepatophyta
“Liverworts”- Simplest bryophytes- Lack conducting cells + Water is passed individually from one cell to another.- Lack cuticle and stomata
Hepatophyta life cycle
Similar to other byophytes, but the achegonium is on the underside of the female gametophyte. Sperm within the antheridium are located on top of the male gametophyte, and must swim up and into the archegonium for fertilization to occur.
Phylum Anthocerophyta
“Hornworts”- Closely related to green algae- Found along waterfalls and riversides, associated with freshwater.- Possess stomata
Alternation of generations
Life cycle of all land plants. Alternation between gametophyte and sporophyte stage. - Gametophytes are (n) and sporophytes are (2n)
Vascular seedless plants
- Dominant plants during Carboniferous period (300-350 million years ago)- Possess conductive tissue- Sporophyte-dominant life cycle + Gametophyte is ephemorous- Large sporophytes and small gametophytes that are independent of one another since they can both photosynthesize.- Posses xylem and phloem- Evolution of roots- Evolution of leaves + Microphylls + Megaphylls- Branching + Allows for more sporangia to be produced- Sporangia arranged in “strobilli”
Xylem
Transports water and nutrients from the soil.
Phloem
Transports food in the form of sugar.
Microphyll
Small leaf. An extension of the stem surrounding by very little tissue with no branching.
Megaphyll
Large branching leaf with soft tissue and veins throughout.
Strobilli
Arrangement of sporangia, densely aggregated along a stem.
Homosporous sporophyte
Produces one type of spore and thus one type of gametophyte. This gametophyte will be bisexual and is able to produce both egg and sperm.
Heterosporous sporophyte
Contains separate structures to produce either megaspores or microspores. Megaspores produce female gametophytes which produce eggs, whle microspores produce male gametophytes which produce sperm.
Vascular seedless plant phylums
- Phylum Lycophyta- Phylum Psilophyta- Phylum Sphenophyta- Phylum Pterophyta
Phylum Lycophta
“Club mosses”- Extinct/extant + Extinct species include small trees- Possess microphylls- Gametophyte may be unisexual or bisexual, dependent on species- Possess strobilli- Major group in coal formation- E.g., Lycopodium, Selaginella, Isoetes
Phylum Psilophyta
“Whisk ferns”- Extinct/extant- No roots or leaves- Dichotomous branching stems + Always branch in 2- Fused sporangia in the form of a “yellow ball”- Gametophyte is bisexual- E.g., Psilotum
Phylum Sphenophyta
“Horsetails”- Mostly extinct but some are extant- Stems contain silica- Scale-like leaves at nodes- May have separate vegetative and reproductive shoots- Gametophyte is bisexual- E.g., Equisetum
Phylum Pterophyta
“Ferns”- Many extinct while some are extant- Possess true roots able to absorb nutrition- Possess fronds (megaphylls)- Possess a “fiddlehead”- Possess “sori”- Gametophyte is mostly bisexual
Fiddlehead
Curled up, immature frond.
Sorus (plural “sori”)
Cluster of sporangia
Phylum Pterophyta life cycle
- Spore develops into a bisexual gametophyte.- Gametophyte produces both an archegonium and antheridium.- Fertilzation occurs within the archegonium when sperm enters.- Zygote develops into a new sporophyte but stays attached to the gametophyte.- Fiddleheads sprout from the roots of the sporophyte, creating more sporophytes.- Sori develop on the undersides of the “sprophylls” to protect them from sunlight.- Sporangia, surrounded by an “annulus,” release their spores into the environment.
Sporophyll
Leaf specialized for spore production.
Annulus
Specialized cells that surround the sporangia of a fern and aid in the release of spores.
Roots do not possess ___ because they are not exposed to light.
Chloroplasts
___ tend to survive better in soil while ___ tend to survive better terrestrially.
Gametophytes, sporophytes
Vascular seed plants
“Gymnosperms” and “Amgiosperms”Terrestrial adaptations:1. Reduced gametophytes2. Heterospory3. Pollination4. Seed5. Defense mechanisms
Reduced gametophytes in seed plants
Seed plants contain “ovules” and “pollen grain” which are retained and protected in moist sporophytic reproductive tissues.
Heterospory
Male and female spores are produced in different structures. - Characteristic of all seed plants.
Pollination
Transfer of pollen from the male reproductive organ to the female reproductive organ, or “stigma.” - Done mostly by wind and replaced swimming for sperm delivery to egg.
Seed
A dormant embryo with surrounding nutrients protected from environmental conditions. - Results from the fertilization of an “ovule.” - Contains roots, stems, and leaves of the young sporophyte. - Requires water to germinate. - Seeds replaced spores as dispersal agents, using wind, water, or animals for more efficient dispersal.
Defense mechanisms
Secondary compounds already present in non-vascular and vascular seedless plants are utilized for defense in seed plants. - May produce toxins - May release pheremones when attacked in order to attract predators of their attacker.
Gymnosperms
“Naked seed plant”- Do not produce flowers- Complex vascular system + True roots, stems, and leaves- Gametophyte is reduced and retained on as well as fed by the sporophyte- Reproduce via cones- Ovules/seeds exposed within cone- Classification of gymnosperms + Phylum Cycadophyta + Phylum Ginkgophyta + Phylum Gnetophyta + Phylum Coniferophyta
Phylum Cycadophyta
“Cycads”- Evolved 320 million years ago, highly diverse in Mesozoic era- 130 extant species- Palm-like leaves- Highly toxic compounds- May reach 18’ tall- Reproduce through “dioecious” cones + Beetles play large role in transporting pollen grain to ovule- E.g., Coontie
Dioecious
Male plant will possess only male cones and female plant will possess only female cones.
Coontie (Zamia integrifolia)
- Contains “cicasin” which is deadly unless cooked.- Only North American cycad.- Produces a neurotoxic chemical called “cicasin.”- Atala butterfly feeds on and absorbs its toxin.
Phylum Ginkgophyta
- Mostly extinct- Ginkgo biloba is the only surviving species- Fan-like leaves- Dioecious- Cones resemble fruit- Ciliated sperm
Phylum Gnetophyta
- Share characteristics with other gymnosperms as well as flowering plants- Fleshy leaves- Strobilli are similar to some inflorescence, or flower clusters- 3 genera + Gnetum + Welwitschia + Ephedra (previously used as a medication until it was found to be liver-toxic)
Phylum Coniferophyta
“Conifers” or “evergreens”- Oldest, tallest, largest trees- Sporophyte will produce both male and female cones- Possess needles, leaves adapted to dry conditions that do not fall off + Often experience drought in the winter + Bald cypress is the only species to lose its needles- Used for lumber, paper, etc.- E.g., Sequoia (red wood), pines, junipers, cypress, etc.
One bristlecone pine was found to be ___ years old.
4,600
Wollemia pines, only known from ___ ___, were rediscovered in Australia in 1994.
Fossil records
Phylum Coniferophyta life cycle
- Female possesses ovulate cones + Contain magastrobilus with megasporophylls (scales), micropyle.- Male possesses small staminate (pollen) cones + Staminate cones contain microstrobilus with microsporophylls.- Sporogenesis forms spores- Gametogenesis forms gametes
Cone is made out of ___ ___.
Modified leaves
Pollen grain
Male gametophyte or “microspore” - Strobili on the staminate cone of the mature sporophyte contain microgsporangium with microsporocytes. These microsporocytes undergo meiosis to produce pollen grain.
Ovule
Female gametophyte or “megaspore” - Ovulate cone will contain 2 ovules within each scale. + Ovule consists of megasporocyte (megaspore mother cell), which is inside of the megasporangium, which is inside of the integument (tissue that will become the seed coat).- Megasporocyte undergoes meiosis to produce 4 megaspores. Only one megaspore survives.- The surviving megaspore undergoes mitosis to become a multicellular female gametophyte.- Resulting megaspore contains an egg within an archegonium within the megasporangium within the integument. This ovule is now ready for fertilization.
Formation of the seed
- Pollen grain enters the unfertilized ovule via a small opening called the “micropyle.”- Pollen grain germinates within the integument. Releases two sperm via a “pollen tube” and one fertilizes the egg while the other degenerates.- Following fertilization, sporophyte embryo begins to develop.- Surrounding female gametophytic tissue develops into “endosperm” (n) which feeds the embryo.- Integument surrounding the endosperm develops into seed coat (2n) that protects the embryo.- Embryo is now a new sporophyte and ovule is a seed ready for germination.
Seed layers
- Seed coat (2n)2. Endosperm (n)3. Embryo (2n)
Staminate cone
Male cone (modified leaves)
Ovulate cone
Female cone (modified branches). Ovules reside in the scales of the cone.
Pollination in pines does not occur for ___ ___ as the pollen tube grows.
12 months
Monoecious
Both sexes are found on the same plant. - E.g., most pines.
What happens to the remaining female gametophyte after the sporophyte emerges?
It is absorbed by the sporophyte for nutrition since it is now able to photosynthesize on its own.
Angiosperms
“Seeds within a container” - Refers to the fruit suroundign the seed. Serves as the ovary wall. - Phylum Anthophyta
Genus Amborella
Considered to be least advanced of the angiosperms because they still have cone-like structures. - E.g., magnolias
Structure of a flower
Whorls from outside in: - Sepals - Petals - Stamen + Anther & filament - Pistil/Carpel + Stigma, style, ovary, & ovuleAll of the above are modified leaves.
Sepal
Green, outer leaves of the flower.
Stamens
Male sex organs containing developing male gametophytes. - Consists of the anthers at the end of the filament.
Anthers
Contain microsporangium with microsporocytes.
Pistil/carpel
Female sex organ containing developing female gametophytes. - Consists of the stigma, style, ovary, and ovule.
Stigma
Receives pollen grain
Style
Channel through which pollen grain must travel from stigma to ovary.
Ovary
May contain multiple ovules and is encased within the receptacle.
Perfect flowers
Flowers with both male and female reproductive organs.
Imperfect flowers
Flowers that are either staminate or ovulate.
Complete flowers
Flower containing all four structures/whorls, including both male and female reproductive organs. - Monoecious - Typical of more primitive flowers
Incomplete flowers
Flower missing one or more of the four structures/whorls, usually the male or female reproductive organs.
Simple flowers
Contain one flower per stem.
Inflorescence
A group of flowers on the same stem. - E.g., sunflower
Transfer of pollination in flowers occurs by…
- Insects (most common) + Attract insects by producing nectar or pollen grain.- Wind (not common in angiosperms, corn is an example)- Birds (hummingbirds)- Mammals (bats)- Water (less common)Flowers and animal pollinators have coevolved to have a mutualistic relationship.
Largest flowers
- Rafflesia (parasitic)- Carrion flower
The ovary wall develops into the ___.
Fruit
Fruits may be either ___ or ___.
Fleshy, dry
Types of fruits
- Simple fruit- Aggregate fruit- Multiple fruit
Simple fruit
Ovules are all contained within a single ovary. - E.g., peas
Aggregate fruit
Contains multiple ovaries. - E.g., raspberry (the little balls are the ovaries)
Multiple fruit
Each segment develops from the carpel of one flower. - E.g., pineapple
Monocots
- One cotyledon (or seed leaf within the seed) + Absorb nutrients- Parallel veins- Scattered vascular tissue- Fibrous roots + No main root- One opening in pollen grain- Floral organs in multiples of three
(Eu)dicots
- Two cotyledons (or seed leaves with the seed) + Absorb nutrients- Net-like veins- Vascular tissue arranged in a ring- Taproot system + One main root- Three openings in pollen grain- Floral organs in multiples of four or five
Another name for “fruit dispersal” is ___ ___.
Seed dispersal
Methods of fruit/seed dispersal
- Animals- Wind- Water
The pollen tube is able to grow by feeding on the ___ ___.
Female gametophyte
Development of the male gametophyte in angiosperms
- Anthers contain “pollen sacs,” or microsporangium containing microsporocytes.- Microsporocyte undergoes meiosis to create 4 (n) microspores.+ From here, process is now all (n).- Each of the four microspores undergoes mitosis to produce four two-cells pollen grains. + Each microspore contains one generative cell and one tube cell.
Generative cell
Divides by mitosis to form two non-flagellated sperm cells that participate in fertilization.
Tube cell
Forms the elongating pollen tube that delivers the sperm to the embryo sac.
Development of the female gametophyte (embryo sac)
Occurs within the ovule:- Megasporocyte undergoes meiosis to form 4 (n) megaspores.+ From here, process is now all (n).- Only one megaspore survives and absorbs the cytoplasm of the other 3, making it very large.- Megaspore undergoes mitosis 3 times to form 7 cells and 8 separate nuclei within the embryo sac. + 3 antipodal cells + One polar call - Contains 2 identical polar nuclei (n+n for now) + 1 egg + 2 synergids
Double fertilization
- Pollen grain germinates and discharges 2 sperm into the embryo sac.- One sperm fertilizes the egg, forming a (2n) zygote.- Other sperm fuses with the 2 polar nuclei, creating a (3n) cell that develops into (3n) endosperm.
Angiosperm seed ploidy
- Embryo (2n)- Seed coat (integument) (2n)- Endosperm (3n)
Angiosperm life cycle
- Microspores (n) are released from the microsporocytes (2n) within the anthers.- Pollen grain travels via the stigma, down the style, and forms a pollen tube to reach the embryo sac.- Two sperm are discharged and one fertilizes the egg, forming the zygote, while the other fuses with the polar cell, forming the (3n) endosperm.- Seed germinates when the new sporophyte emerges and root system begins to develop.- Sporophyte absorbs remaining female gametophyte.
Asexual reproduction of angiosperms
No spore involvement. New plants are able to sprout from the roots and shoots of plants. Rhizomes can sprout new roots and shoots in angiosperms.
Heterosporic plants can only reproduce ___.
Sexually
Plants and biotechnology
- Plant tissue cultures + Using just a few cells can lead to the formation of a complete plant.- Protoplast fusion + Type of genetic modification in which two plants are combined to create a hybrid.- Genetically engineered plants + All cotton and corn is genetically engineered. Also common in soybeans and rice. + Injection of keratin, or vitamin A, will turn the food source yellow.
The embryo sac contain ___ cell with ___ genetically identical nuclei.
One, two
