Please enable JavaScript.

Coggle requires JavaScript to display documents.

An Introduction to Plant Biology (Plant Structure #, Genetics and…

- - - - develops into a fruit.
- - - - palms
    - - Typha
    - - Canna lilies
- - - - Fabids
      - malvids
    - - have iridoid compounds
      - lamiids
      - campanulids
- - - - The type of allele that a single individual has are called genotype.
    - - The expression of the alleles in the individual's size, shape, or metabolism is called Phenotype.
- - - - Step 1
        
        DNA double helix unwinds.
      - Step 2
        
        DNA helicase unzips DNA
      - Step 3
        
        DNA polymerase helps in pairing up free nucleotides with exposed bases. Polymerase adds nucleotides to the 3' end of the growing nucleic acid.
      - Step 4
        
        Weak hydrogen bonds form between complimentary bases.
      - Step 5
        
        Covalent bonds form between adjacent nucleotides.
      - Step 6
        
        Two identical daughter molecules are formed. Semi conservative replication occurs as each resulting double helix contains one new molecule and has conserved one old one.
- - - - Neither parental trait dominates the other, so the pair of alleles shows incomplete dominance.
    - - When a plant's own pollen is used to fertilize its own eggs, the cross is selfing.
    - - Dominant allele is exposed and Recessive is not exposed.
    - - Genes exist in many forms.
  - - - Alleles of Genes on separate chromosomes move independently to alleles of another gene.
- - - - sporophytes are always diploid.
    - - Plant spores undergoes mitosis and grows into an entire new haploid plant called gametophyte.
      - Mammalian gametes are of two types
        
        microgametes
        
        They are small sperm cells.
        
        microgametophytes (male)
        
        grown from microspores
        
        megagametophyte ( female)
        
        grown from megaspores
        
        megagametes
        
        also known as oogamy.
  - - - these are lowermost and outermost of the four floral appendages.
    - - petals together make up corolla. Sepal and petals together constitute flower's perinath.
    - - Above the petals are stamens, collectively called androecium.
      - have two parts
        
        filament
        
        it is the stalk.
        
        anther
        
        pollen is produced here.
        
        neighboring anther cells in a layer called the tapetum act as nurse cells.
    - - constitute gynoecium
      - has three parts
        
        stigma
        
        it catches pollen grains
        
        a style
        
        it elevates the stigma to a useful position
        
        an ovary
        
        where megaspores are produced.
        
        inside the ovary is placentae
        
        it holds ovules.
        
        the ovule has a central mass of parenchyma called a nucellus.
        
        Some nucellus cells enlarge in preparation for meiosis: these are megaspore mother cells or megasporocytes.
      - Gametophytes
        
        Microgametophyte
        
        microspores develope into microgametophyte.
        
        microspores nucleus divides mitotically producing a
        
        Vegetative cells
        
        generative cells
        
        Megagametophyte
        
        embryo sac is multinucleate megagametophyte.
        
        The seven cells are one large central cell with two polar nuclei
        
        three small antipodal cells
        
        an egg apparatus
        
        consisting of two synergids
        
        and an egg.
      - Fertilization
        
        Syngamy of sperm and egg involves both plasmogamy and the fusion of the protoplasts of the gametes and karyogamy.
        
        a large endosperm nucleus is established
        
        both sperm nuclei undergo fusions one with the egg nucleus and the other with the polar nuclei- the process is called double fertilization.
      - Embryo and seed development
        
        Suspensor, which pushes the embryo deep into the endosperm
        
        radicle
        
        epicotyl
        
        hypocotyl
        
        albuminous seed are a mature seed in which endosperm is rather abundant.
        
        if endosperm is sparse or absent at maturity, the seed is exalbuminous.
        
        Seed coat
        
        The integument that surround the nucellus expand and mature into the seed coat.
      - Fruit development
        
        As the ovule develops into a seed, the ovary matures into a fruit.
        
        has three layers.
        
        exocarp is the outer layer
        
        mesocarp is the middle layer
        
        endocarp is the innermost layer.
- - - - the life cycle consist of four types of plants
        
        microgametophytes
        
        megagametophytes
        
        staminate sporophytes
        
        carpellate sporophytes
- - - - has only limited potetntial for growth.
- - - - The relationship between area and species richness is called Species-area relationship
    - - It is obtained by plotting the number of species in each abundance class.
- - - - Feeding rate ( how quickly a predator find a new prey individual)
      - Handling time ( the amount of time needed to consume the prey)
    - - Zero growth isocline ( The line indicating population stability is Zero growth isocline)
    - - If the population falls to less than half its carrying capacity, the fixed effort harvest will remove fewer individuals from the population than are recruited into it, and the population will grow. This is one way in which a fixed effort harvest is less risky than a fixed quota harvest.
  - - - Foragers maximize fitness by maximizing energy intake rate
      - 2.Food items are encountered one at a time and in proportion to their abundance
      - 3.All food items in the environment can be ranked according to their profitability
        
        Profitability – the energy it contains divided by its handling time
    - - Exploitation competition ( Exploitation competition occurs indirectly through a common limiting resource which acts as an intermediate. For example, use of resources depletes the amount available to others, or they compete for space) .
      - Interference competition ( one organism prevents other organisms from using the resource) .
      - Apparent Competition ( Apparent competition is a type of indirect interaction that is defined as a negative effect of one species on the population growth rate or abundance of another species, mediated through the action of shared natural enemies. It can occur whether or not the two species compete directly for resources)
- - - - Both branches being of equal size and vigor.
  - - - Prostele
        
        The center is a solid mass of xylem with no pith.
      - Endarch Prostele
        
        Protoxylem is located in the center and metaxylem differentiates on the outer edge of the xylem mass.
      - Exarch Prostele
        
        Metaxylem is located in the center of the xylem mass and protoxylem on the edges as several groups next to the phloem
      - Siphonostele
        
        Pith is present in the center.
- - - - clusters of sporangia
- - - - Pertica displays pseudomonopodial branching
  - - - leaves on gametophytes of non vascular plants
      - enations of zosterophyllophytes and lycophytes
      - megaphylls, leaves
- - - - Class Musci
      - Class Hepaticae
      - Class Anthocerotae
- - - - The leafy stems, known as gametophores of many moss plants grow close together , tightly appressed and forming dense mounds.
    - - The innermost cortex is composed of cells called hydroids that conduct water and dissolved minerals.
      - At the base of the stem are rhizoids which are small, multicellular trichome-like structures that penetrate the surface of the substrate.
    - - Gametophore growth begins when a spore germinates and sends out a long, slender chlorophyllous cell which undergoes mitosis and produces a branched system of similar cells; the entire network is a protonema
    - - Sperms are produced in microgametangia called antheridia and Eggs occur in megagametangia called archegonia.
- - - - They can be very easily confused with mosses. They have typical lobed leaves, which grow from two apical points and their basal pouch.
    - - They have thick bodies and are not easily confused with mosses.
- - - - Upright cells
      - Procumbent cells
- - - - These are long tapered cells, it produces two elongate cells.
    - - These are short and more or less cuboidal, They undergo periclinal cell divisions, with one of the daughters remaining a cambial ray initial and the other differentiating into either xylem parenchyma ( inner) or phloem parenchyma ( outer)
- - - - Cork cambium is also called phellogen, its cells are like ray initials.
        
        The inner cell remains cork cambium after division whereas the outer cell differentiates into a cork cell also known as Phellem cell.
        
        Phelloderm ( A layer of Parenchyma cells ) is produced by the cork cambium.
        
        The cork cambium, the layers of cork cells, and the phelloderm are known as periderm.
- - - - Mid rib
        
        lateral veins
        
        minor veins ( helps in releasing water from xylem and loading sugar into phloem)
        
        Many fibers arranged in a sheath, called bundle sheath.
- - - - For example, mango, peanut, peas etc.
  - - - For example, rice , wheat, maize etc.
- - - - Mutations
      - Accidents
      - Artificial selection
        
        It is the process in which humans purposefully change the allele frequency of a gene pool.
      - Natural selection
        
        Also known as survival of the fittest, those individuals that are most adapted to an environment survive, whereas less adapted do not.
        
        Factors that are not part of Natural selection are purpose, intention, planning, or voluntary decision making.
        
        Situations in which Natural selection does not operate
        
        It does not operate if all individuals of a population are identical genetically or if it is impossible to become adapted to a certain condition.
        
        Multiple selections pressure
- - - - The original species is physically divided into two or more populations that cannont interbreed: if speciation results, it is called allopatric or geographic speciation.
    - - Any biological phenomenon that prevents successful gene flow is a biological reproductive barrier.
      - When two groups become reproductively isolated even though they grow together, the result is sympatric speciation.
      - When pollens are prevented from moving one plant to another, neither pollination nor fertilization occurs. Consequently these are called Prezygotic isolation mechanisms.
      - The large number of unique, characteristic alleles, each may become sufficiently distinct phenotypically that the two subpopulations can no longer interbreed. Their genomes are two different called postzygotic internal isolation barriers.
        
        The earliest postzygotic barriers to arise is hybrid sterility.
        
        When zygote or embryo dies early in development , this is called hybrid inviability.
- - - - stomatal pore open leads to
        
        water loss ( transstomatal transpiration)
        
        Some water is lost directly through the cuticle by (transcuticular transpiration)
        
        Water is pulled up through tension in xylem.
- - - - The roots are going to have lower potential of water than soil. So, water moves from soil to root.
- - - - For example, radish, tobacco seedling etc.
    - - For example, maize, wheat etc.
- - - - Casparian strips are involved in controlling the types of minerals that enter the xylem water stream.
- - - - Ectomycorrhizal relationship ( fungal hyphae penetrate between the outermost root cortex cells but never invade the cells themselves ).
      - Endomycorrhizal association ( in which hyphae penetrate the root cortex as far as the endodermis, but cannot pass the casparian strip
- - - - They have primary walls that remain thin
    - - These cells have a primary wall that remians thin in some areas but becomes thickened in other areas, most often in the corners.
    - - These cells has both a primary wall and a thick secondary wall, walls are elastic and can be deformed.
      - Types of Sclerenchyma
        
        Mechanical ( non conducting) sclerenchyma
        
        Sclereids ( Often dead at maturity)
        
        Fibers
        
        Conducting sclerenchyma
        
        Tracheids
        
        Vessel elements
  - - - Vessel elements
      - Tracheids
    - - Sieve cells
      - Sieve tube members
    - - Primary xylem
      - Primary phloem
- - - - Cutin/ waxes ( inhibit the entry of carbondioxide needed for photosynthesis)
- - - - Epidermis
        
        Cork cambium in some plants
        
        Cork
        
        Phelloderm
    - - Primary xylem
      - Primary phloem
      - Fsaciular cambium
        
        Vascular cambium
        
        Secondary xylem
        
        Secondary phloem
        
        Cork cambium
    - - Pith
        
        Interfasciular cambium
      - Cortex
        
        Cork cambium in some plants.
- - - - Climate
      - Soil factors
        
        A horizon is uppermost and consist of litter and debris.
        
        B horizon is the area where materials from the A horizon accumulate.
        
        C horizon is made of rock and rock fragments.
      - Latitude and Altitude
      - Disturbance
  - - - Commensal Relationships , in which one species benefits and other is unaffected for example cocklebur.
      - Predation, in which one species benefits and the other is unharmed. for example Insects laying eggs on Plants
      - Pathogenic, bacteria and fungi are pathogenic causing disease.
- - - - Limiting factor
    - - Random Distribution is when there is no obvious, identifiable pattern to the positions of individuals.
      - Clumped Distribution is in which spacing between plants is either small or large, but rarely average.
      - Uniform Distribution occurs in orchards and tree plantations, all individuals are evenly spaced from their neighbors.
  - - - The number of individuals in each populations that can live in a particular ecosystem is limited, that number is the carrying capacity.
  - - - r-selected species are those that emphasize high growth rates, typically exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood (i.e., high r, low K).
- - - - It is used in chemiosmosis
        
        36-38 ATP per glucose is created
- - - - Aneurophytales
        
        They have more relictual progymnosperms.
      - Archaeopteridales
        
        Reproduction is heterosporous.
    - - Megasporangium
        
        is surrounded by a layer of tissue called integument.
      - Micropyle
        
        a hole in the integument which permits sperm cells to swim to the egg after the megaspore had developed into a megagametophyte and had produced eggs.
      - Pollen chamber
        
        microspores settle here.
  - - - evolved from Aneurophytales
    - - Pollen cone
      - Microsporophyll in cycads may bear many microsporangia
      - Sperm cells of cycads have hundreds of flagella and must swim to the egg cell.
    - - Vegetatively, cycadeoids such as Cycadeoidea were similar to cycads. They had a broad cortex and a tough outer protective layer formed by persistent leaf bases.
  - - - Voltziales
        
        Family Voltziaceae , Lebachia
      - Coniferales
        
        Family
        
        Pinaceae
        
        Pine
        
        Two types of shoots
        
        Long shoots
        
        Short shoots
        
        Simple cones
        
        Araucariaceae
        
        Agathis
        
        Taxodiaceae
        
        Sequoia
        
        Podocarpaceae
        
        Podocarpus
        
        Cupressaceae
        
        Juniperus
        
        Cephalotaxaceae
        
        Cephalotaxus
      - Taxales
        
        Family , Taxaceae
        
        Taxus
- - - - G1 phase
        
        It is the first stage after division, the cell is recovering and conducting most of its normal metabolism.
      - S phase
        
        The genes in the nucleus are replicated in this phase.
      - G2 phase
        
        The cell prepares for division in this phase. Last about 3 to 5 hours.
- - - - Two types of Karyokinesis
        
        Mitosis
        
        It is a duplication division. It consist of four phases.
        
        Prophase (Chromosomes condense, Spindle fiber is formed)
        
        Metaphase (Chromosomes become visible, At the end of the metaphase, separase enzyme digests cohesin. The two chromatids of each chromosmes are free of each other. The no of chromosomes is doubled, but the size of each chromosomes in the cell is halved).
        
        Anaphase (Chromosomes on each side get closer to the end and are pulled together into a compact space).
        
        Telophase (Chromosomes become less distinct because of uncoiling, Most events in telophase are reversals of those in prophase).
        
        Cytokinesis ( This is the division of protoplast).
        
        Meiosis
        
        It occurs only in the production of reproductive cells.
        
        Meiosis II ( The two chromatids of each chromosomes are separated and the resulting nuclei each have a haploid set of chromosomes, each chromosome with only one chromatid)