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Course Mindmap, Tissues and the primary growth of stems (Internal…

- - - - inexpensive to build, requires little glucose; cell walls are only 80-100 nm thick with just 5-10 layers of microfibrils
    - - chlorenchyma cells: parenchyma cells involved in photosynthesis
        
        have multiple chloroplast, has thin walls to allow light and carbon dioxide to pass
        
        pigmented cells (flower petals and fruits) must be parenchyma cells with thin walls because of pigments that are visible.
      - glandular cells: secrete nectar, fragrances, musilage, resins and oils are parenchyma cells
        
        contain few chloroplasts, have elevated amounts of dictyosomes and endoplasmic reticulum
        
        transport sugar and minerals, use them metabolically, transport product out
      - transfer cells: mediate short-distance transport of materials are parenchyma cells
        
        have large extensive membranes which hold numerous molecular pumps
        
        increase their surface area with extensive knobs, ridges
    - - some die at maturity so pollen, seeds, and gas may be released
  - - - wind, animals or snow are detrimental
    - - sclereids have strong walls on all three sides, both brittle and strong at same time
      - conducting sclerenchyma transports water
- - - - nodes: where the leaves are attached
      - internodes: region between nodes
      - leaf axil: stem area just above where a leaf attaches
      - axillary bud: within leaf axil, miniature shoot with a dormant apical meristem and several young leaves
        
        if its a vegetable bud it'll grow in a branch, if its flower bud it will grow in to flowers or group of flowers
      - bud scales: small corky wax that protects the delicate organs inside
      - terminal bud: at the very tip
    - - alternate phyllotaxy: leaves alternate up the stem, one leaf at each node
      - opposite phyllotaxy: two leaves per node
      - three or more leaves per node is whorled
      - distichous phyllotaxy: leaves are arranged in only two rows, like corn
      - decussate phyllotaxy: leaves are arranged in four rows, only in species with opposite leaves
      - spiral phyllotaxy: each leaf is located slightly to the side of the on immediately above or below it, most common arrangement
- - - - shields delicate internal cell from abrasion by dust particles, passing animals, leaves and stems that might rub together
      - reflectivity protects the plant from overheating in the sunlight
    - - builds up as a layer called cuticle
      - when cuticle isn't enough it will have a layer of wax, which together resist digestive enzymes and provide defense against pathogens
    - - guard cells have a radial arrangement of cellulose microfibrils which makes the opening of the stomatal pore possible
      - guard cells swell when absorbing water and the walls on the back are weak and form an arc which creates the opening
      - after photosynthesis is done and the stomatal pores close, somethings a trichomes forms
        
        "hairs" elongate outward making it hard for plants to land on or animals to chew on
  - - - open tissue with large intercellular air spaces
    - - these have large cortical air chambers which gives buoyancy
    - - water and minerals enter through the roots and the xylem sap travels through dead, hollow cells
      - when its in the shoots, most water evaporates the rest and the minerals is used by surrounding cells
    - - cells are living, they pick up sugar where there is plenty and it transports the sugar where its needed
  - - - young cell matures into a treachery element it must enter cell cycle arrest and stop duplicating first
      - initially a small parenchyma cell with a thin wall but becomes long , narrow and then deposits a secondary wall #
        
        once secondary wall is reinforced the cell dies leaving a hollow tubular wall
        
        primary wall must remain uncovered for water to enter and leave the cell because secondary is impermeable to water
        
        annular thickenings set of rings that are the secondary wall, what allows water in and out of cell, not very strong
        
        helical thickening: gives support to the primary wall, secondary wall exists as three helices
        
        scalariform thickening provides more strength
      - treachery elements with annual thickening are weak but a large percentage of there primary wall is free on the secondary wall
      - pitted element s are the oposite , they are very strong but water leaves and enter slowly because of the secondary wall lining
      - tracheids obtain water from other tracheids below them and pass it onto ones above
        
        must be near each other with overlapping
        
        Pitts are aligned so that water can pass through
        
        aligned set of pits is a pit pair and the set of primary walls and middle lamella between them makes a pit membrane
        
        very permeable to water, but does offer resistance
      - vessel elements provide a way to move water with less friction then tracheids
        
        are individual cells that produce both primary and secondary walls
        
        however an entire region of primary and secondary wall is missing
        
        during the final stage of differentiation a large hole called perforation is digested through a particular site of the primary wall
        
        an entire stack of vessel elements is a vessel, on each end of a vessel is only one perforation
        
        vessels must absorb water from parenchyma cells, tracheids, or other vessels and they must pass it on
  - - - they are parenchyma cells, primary walls only and must remain alive to conduct
      - immature sieve elements begin to differentiate and enlarge to a diameter of more then 1 mcm that is when there called sieve pores
      - plasmodesmata occurs in groups and create sieve areas
      - sieve elements stay alive during differentiation and the plasma membrane continues to line the sieve pore
      - cytoplasm within the pore also increases and rapid, bulk movement from cell to cell happens
      - sieve pores must be aligned for phloem sap to pass through
      - sieve elements that have cells that are elongate and spiel shaped and sieve areas all over it is a sieve cell
        
        evolved first, found in fossils and in non-angiosperm vascular plants
- - - - these sieve elements don't have a secondary wall so they are identical
      - cells closet to the metaxylem become metapholem
        
        cells are smaller then metaxylem
    - - have had the longest time for growth before differentiation, they develop into metaxylem
      - constitute the first xylem to appear, called protoxylem
      - visible differentiation begins, certain cells stop dividing and start elongating
      - and differentiating into first tracheids or vessel elements of the vascular bundles
- - - - perpendicular to the petiole, cells involved in cutting off the leaf when its useful life is over.
  - - - leaf flutters also make it difficult for insects to land on leaf and knock those that have already landed
      - long, thin flexible petioles allow blade to flutter in wind, cooling and bringing fresh air
        
        if there's no air, CO2 is absorbed from the vicinity of the leaf faster, which depletes CO2 and decreases photosynthesis
  - - - also called the dorsal surface, large veins abaxial side, upper side ventral surface
    - - light harvesting portion is called leaf blade
- - - - although the leaf appears highly modified it is similar to foliage leaves
        
        epidermis must be absorptive, and throat of the pitcher contains numerous trichomes
        
        most significant difference is the lamina is tubular not flat
        
        it has numerous stomata and vascular bundles, and mesophyll that contains aerenchyma and chlorenchyma
        
        it is thin, parenchymatous, and capable of photosynthesis
      - this happens because the habitats lack nitrogen and ammonia
    - - they use the object for support as it continues to elongate
      - when they touch something the side facing the object stops growing and the opposite side continues to grow
      - they grow indefinitely and contain cells that are capable of sensing contact
  - - - no mesophyll parenchyma or vascular tissue, instead has closely packed fibers
        
        after fiber mature, they deposit lignin, which makes them hard and resistant to decay
      - are needle shaped, inhibit lamina formation
      - spines are their axillary buds
    - - petiole is either very small or absent because the bud scale must remain close to stem
      - are small and rarly compound
      - bud scales protect these by forming a tight layer around stem tip
        
        are tougher and waxer then regular leaves, can produce a thin layer of corky bark
      - in perennial plants, dominant shoot apical meristems are protected from low temps and drying wind
  - - - most leaves are perennial, consequently the plants are evergreens
      - leaves are always simple, have only few forms
      - they have thick cuticles, epidermis and hypodermic cells have thick walls
    - - such plants are sclerophyllous and leaves are sclerophylls
        
        cuticle is usually very thick and waxes are abundant
        
        sclerenchyma is often present as a layer just below epidermis and in bundle sheaths
      - result makes leaf hard, which makes it more resistant to animals, fungi, freezing temps, and UV light
      - extended lifetime and prolonged productivity
      - live more then 2 years
  - - - photosynthesis occurs more deeply then foliage leaves
      - lack of air spaces, makes mesophyll more transparent, allowing light to penetrate further
      - reduces internal evaporative surface area and water loss through stomata
    - - has an automatic consequence of reducing the capacity of CO2 uptake
      - reduction in surface area is advantageous for water retention
      - spherical is the optimal surface-to-volume shape
      - some leaves are cylindrical or even spherical
- - - - water molecules are trapped in quiet air and may diffuse back to stomata, stomata is greater in lower epidermis than upper.
      - however, air tends to be trapped on the underside of the leaf, so water lose from stomata there is not significant
      - if stomata in upper epidermis are open and loosing water, the water molecules are swept away by convection
      - sunny day, leaf is warmer then surrounding air, thus heats air and convection currents rise
      - stomata being concentrated on bottom has its benefits,fungi, and bacteria typically land on the top of the leaf
        
        leaf stomata are usually sunken into epidermal cavities, creates a region of nonmoving air
    - - guard cells and trichomes, may be abundant
      - large percentage of flat tabular ordinary epidermis cells
      - leaf epidermises are often remarkably hairy, trichomes can affect leaf biology
        
        provide shad on upper surface but prevent rapid air movement and slow water loss from stomata #
        
        makes it difficult for insects to walk on plant, sometimes makes them vulnerable
        
        can even recreate stinging compounds which prevents animals from eating
        
        if large enough can protect small insects from predators so they can reproduce on leaf
      - like stem, leaf epidermis contain a coating of cutin and usually wax on their outer walls
    - - a serious problem if the soil is to dry and roots cannot replace lost water
      - water lost through epidermis is called transpiration
  - - - main photosynthetic tissue of plants
      - cells are separated slightly so that each cell has most of its surface exposed to intercellular spaces
      - cells being separated helps with CO2 absorption
      - typically only one layer thick but it places with intense sunlight can be multiple layers thick
    - - open loose aerenchyma that permits CO2 to diffuse rapidly away from stomata
    - - leaves held horizontally(most leaves) sun is overhead
        
        palisade parenchyma near the upper surface permits max absorption of light and photosynthesis
      - leaves held vertically, both sides are equally illuminated, and palisade parenchyma is functional on both sides
  - - - an eudicot leaf usually has one large midrib, lateral veins emerge into narrow minor veins
      - minor veins are important for releasing water from xylem and loading sugar into phloem
      - midrib and lateral veins are involved in conduction
      - vein structure size varies
        
        midrib and lateral veins are both primary xylem on upper side, and phloem on lower side
        
        because they both conduct and support leaf blade, they may have fibers arranged as a sheath
        
        a bundle sheath is around the vascular tissue, makes it hard for insects to chew on vascular tissue
        
        minor veins are sites of material exchange and must have a large surface area in contact with palisade and spongy mesophyll
        
        they do not contain fibers or other nonconducting cells
        
        some endings consist of only xylem and in others only phloem, but typically have both
    - - help give rigidity to blades
      - believed to provide an additional means by which water moves from bundle out to mesophyll #
  - - - arrangement of tissues differs at the two ends
        
        epidermis contains fewer stomata and trichomes then lamina
        
        petiole mesophyll is rather like cortex, somewhat compact, not especially aerenchymatous
        
        considerable collenchyma is present if petiole supports a heavy lamina
      - Vascular tissue are the most variable
        
        one, three, five or more vascular bundles are called leaf traces
        
        branch from stem vascular bundles and diverge towards the petiole
        
        may remain distinct or they fuse into a single trace near or in petiole
      - in many species, petiole bears two small flaps of tissue at its base called stipules
        
        they may protect the shoot apical meristem
        
        contribute a significant amount of photosynthesis in some plants
        
        usually when leaf is mature they are very small and die early
- - - - the lamina meristematic cells remain active mitotically
      - the lamina grows a meristem located at its base, which attaches to the top of sheathing leaf base
    - - shoot apex enlarges, forms new stem tissue and next leaf primordium
        
        which will develop inside the previous leafs sheathing tube
      - outer surface of tube is abaxial epidermis, inner is adaxial epidermis
  - - - row of cells grow outwards initiating the lamina, resulting in a young leaf with a midrib and two small wings
        
        during lamina expansion, stomata, trichomes and vascular bundles differentiate, petiole becomes distinct from midrib
        
        all cells in wings are meristematic, their division and expansion enlarge the lamina rapidly
      - as it grows upwards it increases in thickness, establishing the midrib
      - form a connection with the young bundles in the stem
      - a strand of cells in the center differentiates into pro vascular tissue and then primary xylem and phloem
      - all cells are meristematic, with dense cytoplasm and small vacuoles
      - the primordium consist of leaf protoderm and leaf ground meristem
      - grows rapidly that it becomes taller than the shoot apical meristem
      - extends upward as a narrow cone,
- - - - eventually the host tree dies, leaving the strangler fig as a self supporting tree
      - before to long the trunk of the host in encased in numerous strangler fig roots
      - when the roots finally reach the soil it penetrates and rapidly branches
      - for most and even years the roots don't touch the soil , so they must get nutrients from rain water on the tree
      - which then grows rapidly and wraps around the tree extending downwards
      - when the seed germinates , its roots cling to the bark of the host branch
      - birds eat the fruit of the figs and deposit the seeds onto different branches of other trees
    - - surprisingly most parasites attack only the xylem
      - however, haustoria typically remains firmly to their host
        
        penetration either occurs by forcing a shaft of cells through the dermal system
        
        or by expanding the haustorium radically, cracking hosts epidermis
        
        either by adhesive or growing around a small branch or root
      - parasitism has evolved several times
      - in most cases very little root-like structure remains
  - - - causing adjacent cortical cells to undergo mitosis and form root nodule
      - infection thread penetrates once cell after the other all the way into inner cortex
      - bacterium then attaches to the convex and pushes the infection thread
      - bacteria free in the soil secretes a substance which causes root hair to curl sharply
      - sum plants have a relationship with anitrogen-fixing bacteria
    - - endomycorrhizal association
        
        they invade the cells but do not break the host plasma membrane
        
        cannot pass the casporian strips
        
        herbaceous plants have a hyphae that penetrates the root cortex
      - ecotomycorrhizal relationships happens in woody forest plants
        
        but never invade the cells themselves
        
        fungal hyphae penetrate between the outermost root cortex cells
  - - - the contraction is caused by changes in the shapes of the cortex cells
        
        the vascular tissues buckle and become undulate
        
        they simultaneously shorten and expand rapidly
      - because the root is firmly fixed, the stem is pulled downward
        
        in the case of bulbs it gets buried deeper
        
        this makes the base of the shoot kept at soil level
    - - although they live in rainforests, they are adapted to drought conditions
        
        the velamen acts as a waterproof barrier
        
        the root epidermis called velamen is composed of several layers of dead cells
      - and often dangle freely in the air
      - their roots spread along the surface of bark
  - - - prop roots and branches can spread and produce massive trees many meters in diameter
      - they also contract slightly and place some tension on the stem
        
        if they undergo a secondary growth and become woody they can be very strong supports
        
        which acts as a stabilizer
      - they transport additional nutrients and water to the stem
    - - in biennial species, roots are the only permanent organs
        
        its less economical to winter proof the shoot than replace is using the nutrients stored in the root
        
        carbs stored in the root are used to produce a new shoot in the spring
        
        in autumn, most of the stem dies back to a few nodes in the ground
- - - - the arrangement of these differs from the stem
        
        roots of many monocots have strands of xylem and phloem that are distributed in ground tissue
        
        surrounding it is strands of phloem, no pith is present
        
        the xylem of almost all plants except monocots, forms a solid mass in the center
  - - - because they are impermeable, minerals can cross the endodermis
        
        however only if the endodermal protoplasts absorb them
      - cortex cells cannot exert any control without endodermis
    - - their radial walls -top,bottom,sides- are encrusted with lignin and Suberin
      - cells of endodermis have tangential walls, which are thin ordinary primary walls
  - - - or by absorption into the cytoplasm of a cortical cell and then transferal from cell to cell
      - done by either diffusion through the walls and intercellular spaces
      - most significant activity is the transfer of minerals from epidermis to vascular tissue
    - - no distinct boundary exists between the two
    - - greatly increasing absorption of water and minerals
- - - - in the zone tissues are quite permeable
      - cells begin to differentiate
        
        center is provovascular tissue cells that develop into primary xylem and phloem
        
        outermost cells are protoderm and differentiate into epidermis
      - similar to the shoots sub apical meristem region
    - - central cells do not synthesize DNA
        
        this region is known as the quiescent center
        
        very important because damage happens frequently
        
        if cap or meristem are damaged this center creates a new one
        
        believed to act primarily as a reverse of healthy cells
        
        these cells are more resistant to various types of harmful agents
      - root is more orderly then shoot because it experiences no disruptions
      - regular files of cells can be seen to originate the meristem
  - - - as they are pushed closer to the cap their structure metabolizes and metabolism changes drastically
        
        and the middle lamina breaks down and releases cells
        
        cell's dictyosomes secrete copious amounts of mucigel
        
        endoplasmic reticulum becomes less conspicuous, starch grains are digested
    - - although cells appear to extend through the sides , the root is actually growing through the cap
      - cells on the edge grow towards the sides of the root
      - undergoing cells division with transverse walls
- - - - with apical growth only the extreme tip pushes through the soil
        
        because it pushes through the soil, its constantly damaged and must be renews by cell multiplication
        
        dictyosomes of root cap secrete mucigel, which lubricates the passage of the root through the soil
        
        also causes soil to release its nutrient ions and permits ions to diffuse toward the root
        
        the root apical meristem is protected by a thick layer of cells called root cap
        
        just behind root cap and meristem is a zone of elongation
        
        root hair only form in a part of the root that is not elongating
        
        behind that is the root hair zone, many of the epidermal cells extend out
      - grows very slowly because it is embedded in a solid matrix
      - growth by discrete apical meristem is the only feasible type for longitudinal growth
  - - - most monocots cannot undergo secondary growth
        
        some do increase their size by means of stolons or rhizomes
        
        not just limited to monocots, many eudicots also grow this way naturally #
        
        their horizontal shoots branch and then produce adventitious roots
        
        conducting capacity and leaves can not be increased
        
        after stem is formed, the number of vascular bundles, tracheary elements and sieve tubes are set
      - many eudicots are perennial and undergo secondary growth
        
        this enlarging permits an increase in leaves and fine absorptive roots
        
        results in an increased quality of healthy functional wood in both trunk and root #
    - - most monocots and some eudicots have a fibrous root system
        
        as the plant ages more toor primordial are initiated in the stem tissue, resulting in adventitious roots
        
        these roots increase the absorptive and transport capacity of the root system
        
        as a result root primordial grows outwards and forms the first stage of fibrous root system
        
        this happens because the radicle dies
      - lateral roots can make more lateral roots which results in a highly ramified set of roots
        
        if the plant s perennial and woody the roots undergo secondary growth, producing wood and bark
        
        can become prominently swollen like a taproot
      - the tap root develops from the radicle, after germination it grows extensively becoming the largest root
      - most plants have one taproot which is longer, then many small lateral roots or branch roots
- - - - as the years go on the trunk increases in width and the leaves increase and adventitious roots
        
        this is called establishment growth
    - - truck is primary tissue consisting of vascular bundles
        
        never develops a VC
        
        only contain primary xylem and phloem
  - - - secondary phloem between two bands of xylem is called included phloem
      - cells in outermost secondary phloem reactivate and differentiate into new VC
      - after a short period cambium cells stop dividing and differentiate into xylem
    - - secondary tissue are an irregular matrix of parenchyma , few sieve tubes, vessels and VC
      - has numerous VC around individual vessels or group of vessels
- - - - they keep folding in on each other to create a bigger opening for oxygen to enter
  - - - all these layers are known as the periderm
        
        periderm only offers temporary protection
      - inner cell remains cork cambium and outer differentiates into cork cell
        
        all tissues outside cork cambium make outer bark
        
        secondary phloem btwn VC and innermost cork cambium is inner bark
        
        can produce a cell into the inside to mature into phelloderm
      - cork cambium has cuboidal cells like ray initials #
      - difference is in secondary phloem- now referred to cork cambium or phellogen
- - - - the two regions exist because vessels and tracheas do not
      - lighter, moist outer region is called sapwood
    - - first and last make up one years growth called annual ring
      - late wood "summer wood" have lower proportion vessels
  - - - procumbent cells do not
      - upright cells- have direct connection to axial cells
      - store carbohydrates and other nutrients
    - - in agiosperms, axial contains fibers, gives wood strength and flexibility
        
        "softwoods" conifers/ few or no fibers
        
        "hardwoods" basal angiosperms and eudicots / lots of fibers
      - contains treachery elements, carry out longitudinal conduction of water
        
        important for temporary water reservoir
        
        some immature cells undergo transverse divisions and differentiate into column of xylem parenchyma
- - - - biggest difference is ray produces short cells
        
        mostly parenchyma and albuminous cells
      - very similar to fusiform
    - - longitudinally anticlinal walls increase the number of cells
      - inner daughter cells cause cambial to push outward
    - - one cell becomes fusiform other secondary xylem and phloem
        
        inner remains cambium, outer becomes secondary xylem
        
        outer cell remains cambium , inner becomes secondary phloem
  - - - vascular cambium (VC) has to extend every year
        
        fusiform initials and ray initials for cell type #
        
        during the next growth season apical meristem extends and continues growth
      - some mature parenchyma cells resume mitosis forming imterfascicular cambium ; connects to fc
      - instead they divide and constitute the fascicular cambium (fc)
    - - stop dividing and differentiate into conducting tissue
- - - - potassium and water build occurs to make the halves open
      - pressure in the midrib causes the halves to close
  - - - when they open K+ are actively transported into the guard cells but they can't leave
        
        extra K+ and water causes guard cells to swell
  - - - the actions together are called apoplast
- - - - there's a tube like structure which is called xylem vessels is what transport water up the tree
      - if you cut a tress in half you can see water pouring out of the wood
    - - even though the cuticle and waxes are effective ways to prevent water loss, it still happens
        
        this is called trans cuticular transpiration
      - stoma pores are open and water loss happens naturally
        
        this water loss is called transstomatal transpiration
    - - molecules interact with many other substances making it adhesive
      - water molecules interact strongly with other water molecules
        
        because of this liquid water is said to be cohesive
        
        they behave weakly bound together, frozen molecules strongly bound
  - - - if phloem is cut, sap can continues leak because its under pressure
        
        P-protein and P-protein plug help prepare the damage to stop sap leakage
    - - the amount of sugars and nutrients transported per hour is called mass transfer
        
        can be divided by the cross-sectional area to obtain specific mass transfer
      - in both mechanisms, cells surround sieve elements
        
        has companion cells, parenchyma cells this unit is called STM/CC complex
      - however in other species phloem is loaded by polymer trap mechanism
    - - leaves are the dominant source during summer and spring
- - - - cell wall, membranes and soil particles #
    - - any additives can be very dangerous
  - - - water moves up the tree from the roots and as it goes further up the less water there is
        
        simply because other parts of the tree take some of the water while it moves upwards
- - - - also has intercellular transport which the vesicles migrate through cytoplasm and fuse with organelles
      - this is called active transport
      - uses ATP to force molecules across membrane
    - - differentially/ selective- only allows certain things
        
        aquaporins allows movement to happen more rapidly
        
        helps stop bacteria and viruses from reaching the epidermis
      - completely impermeable- don't allow anything to pass
      - freely permeable- membrane allows all solutes to go through
- - - - each ecosystem contains some members, autotrophs, that bring energy into the system
        
        this whole process is referred to as the energy flow and carbon flow of the ecosystem
        
        at each step most of the food is used in respiration which results in the production of ATP
        
        herbivores "primary consumers" because they eat the primary producers
        
        carnivores are secondary consumers because they eat herbivores
        
        decomposers are fungi and bacteria break down the remains of all types of organisms
        
        autotrophs are known as primary producers
        
        there the first step of any food web
      - basically its feeding levels
    - - competition is intense, natural selection has resulted in habitat partitioning #
      - depends on whether the climate is mild or stressful , soil is rich or poor, and if the species tolerance is broad or narrow
        
        mild climates with rich soil supports an abundance of plant life
        
        stressful climates with poor soil only support a low amount of species
      - refers to the number and diversity of species that coexist in an ecosystem
    - - we know that plants change dramatically with the seasons
        
        late summer and autumn brings changes that depends on the ecosystem
        
        in northern US, herbs die but shrubs and trees develop resting buds
        
        spring is typically a time for renewed activity with production
      - changes that an ecosystem undergoes with time
        
        the time can be as short as a day or can encompass seasons and decades
    - - the classification was the means by which the plant survives stressful seasons
      - trees, shrubs and herbs are the three most useful categories and life forms
      - the physical size and shape of the organisms and their distribution
- - - - intrinsic rate of natural increase "biotic potential" is the number of offspring produced by an individual #
        
        even with optimal conditions the individual has a large percentage of seeds that don't germinate
      - generation time is the length of time from birth of one individual until the birth of an offspring
        
        generation time is used to measure population instead of years
    - - however this technique is mostly used with animals and will be difficult for plants
      - demography is the relative proportions on young, middle-aged and old individuals
  - - - uniform distributions typically happens in orchards and tree plantations
        
        ideal because there is even space between individuals
      - clumped distributions: when the space between plants is to small or large
        
        can be caused by to many seeds
      - random distribution is used when there is no obvious, identifiable pattern to the position of individuals
      - local distribution of individuals living locally is also important
    - - so many things can act as a limiting factor: water, sun, wind, shade
      - a limiting factor determines the health of the plant
- - - - before subpopulation could be called subspecies they were called ecotypes
        
        to test if ecotypes are true they used transplant experiments
        
        discovered that plants can be grown together in common ground
        
        took plants from each site and transplanted them in other sites
      - however if it is disadvantageous its a competition
      - if an interaction is beneficial for both organisms its called mutualism
      - when several individuals occur together the possibility of interaction occurs
    - - just the plant being in the environment effects the habitat
        
        can be beneficial, detrimental or neutral
  - - - disturbances "phenomena" often have a radical effect in the ecosystems
      - latitude contributes to many factors to abiotic environment
        
        some ares days are longer same with nights
    - - after several years the soil starts to change
        
        it has a thick soil layer with three horizons underneath
        
        C horizon is composed mostly of parent rock and rock fragments
        
        B horizon is known for as zone of deposition
        
        minerals from A horizon accumulate, reich in nutrients, humus and clay
        
        A horizon is the uppermost layer and is sometimes called the zone of leaching
        
        consists of litter debris as it breakdowns rainwater moves nutrient to next layer
      - the first plant to invade the soil was called pioneers
        
        soil around this time was very sandy, had large particles and the important minerals were still inside the rocks
      - soils are formed by breakdown of rock
    - - the most important is the hottest and the lowest a climate gets
- - - - allow pigments to enter every reaction, large pigments, not very mobile
      - Allow pigments to make several smaller intermediates, more mobile, easy to control
        
        generates ATP from ADP
        
        photophosphorylation, light energy in plants
        
        substrate-level phosphorylation, compounds with high-energy phosphates
        
        oxidative phosphorylation, last stage of respiration ADP-ATP
  - - - cofactor heme, holds iron atom,
      - iron atom carries electrons and cycles between +2, +3
    - - like cytochromes, transport electrons #
    - - like cytochromes, small protein that carries electrons on copper #
- - - - electromagnetic radiation spectrum: gamma rays, X-rays, ultraviolet light, infrared light, microwaves, radio and visible light.
      - Radiation: treated physically as set of particles called quanta, or as a set of waves
        
        Short wavelengths: cosmic rays, gamma rays, ultraviolet light, large amounts of energy in wave lengths
        
        Long wavelengths: inferred, microwave, radar, radio, little energy in waves
    - - Any material that absorbs certain wavelengths therefore has distinct color
      - photosynthetic pigments transfer absorbed light energy to electrons causing chemical reaction
        
        chlorophyll a: capture some red and blue pigments
        
        because others have high energy quanta
        
        long-wavelength not useful because its to weak to be used for chemical synthesis #
        
        when quanta is absorbed by pigment, electron is activated
        
        goes from ground state to excited state, can be used in chemical reactions
        
        not used returns to stable orbital, emitting a quantum with less energy longer wavelength- release called fluorescence
        
        action spectrum: shows which wave lengths are most effective at powering a photochemical process
        
        chlorophyll a absorbs red 660 nm and blue 440 nm #
        
        absorption spectrum: a graph which shows which wave length are most strongly absorbed
        
        Accessory pigments: wavelengths not absorbed by chlorophyll a
        
        resonance: chlorophyll b absorbs wavelengths chlorophyll a doesn't absorb
        
        doesn't occurre at random, the pigments are held by protons called light-harvesting complex protons
        
        embedded in the thylakoid membrane #
        
        300 chlorophylls, carotenoids and protons are called antenna complex
        
        light strikes the complex and the energy is transferred to a reaction center
        
        only the reaction centers chlorophyll a molecule can donate an excited electron onto an electron acceptor molecule
        
        light energy is unstable, fluoresces can occur, chlorophylls electron must react only with the proper molecule
        
        photosynthetic unit: all pigments and carriers that work together are packed on this granule
  - - - energy excites an electron of P700, gets absorbed by a membrane-bound electron
      - the Fx(transfer electron) absorbs an electron from P700, becomes a powerful reducing agent
      - transferred electron still extremely unstable, Fx passes it onto ferredoxin
        
        in thylakoid membrane, small protein , electrons passed from ferredoxin to an enzyme ferredosin-NADP+ reductase #
    - - molecule of plastocyanin donates an electron to chlorophyll a of the PSI reaction center
        
        its oxidized, lacking an electron, must acquire one
      - receives new electron from cytochrome b6/f complex, which gets an electron from plastoquinone
      - receives electron from another Q, then receives electrons from phaeophytin
        
        chlorophyll a that doesn't contain a magnesium atom, becomes oxidized when it donates an electron to Q
        
        must obtain another electron from chlorophyll a when is absorbs light and is activated
        
        different type of chlorophyll a , its the reaction center of PSII called P680
    - - electrons go through the noncyclic electron transport
        
        goes from water to NADPH
      - electrons go through a cyclic electron transport
        
        cycles the electrons to plastoquinones to create more ATP
      - # # #
- - - - largest and most complex enzymes known, has a molecular weight of about 480,000 daltons
      - can constitute up to 30% of the protein in a leaf, making it the most abundant protein on Earth
    - - gets reduced by NADPH to 3-phosphoglyceraldehyde (PGAL)
      - some PGAL cane be taken out of the chloroplast and used by the cell as sugars, fats, amino acids, etc.
      - remaining PGAL stays in the chloroplast to be used for multiple stoma reactions
        
        goes through constructive metabolism called anabolism, and it consist of anabolic reactions, has to have multiple storage compounds
        
        short term storage: ATP and NADPH can be used in the cell, last briefly
        
        intermediate-term storage: simple sugar and disaccharide sucrose stable enough to go from cell to cell
        
        long-term storage: has starch, lipids because they are stable and very large
- - - - electricity is the biggest though, the lighting triggered chemical reactions which makes it possible for rain to reach the surface
      - heat is another energy used to power reactions
      - UV and gamma radiation was used long ago for energy,
        
        came from the sun and ws locked in the second atmosphere letting of quanta and atoms
    - - this second atmosphere was a reducing atmosphere due to the lack of molecular oxygen
      - we have a second atmosphere because the first one was lost to space
- - - - species rapidly diverges into many new species over an extremely short time line
    - - when two species are isolated and reproduce together it can cause sympatric speciation
      - mutations that cause color change
      - flower color, shape or fragrance can be features that cause this
    - - original species can divide into two or more populations and can't interbreed
        
        mountain ranges are a good example because pollinators do not fly across entire mountain
        
        commonly referred to as allopatric
  - - - can be carried by wind, floods and stream flow
        
        sticking to the fur of different animals, trapped above water on different debris
    - - if pollen grains sperm cells fertilize an egg, a new seed develops with an embryo which has all new DNA
      - new allele is carried by some pollen grains allowing it to travel a great distance
    - - critical feature* beneficial allele arise and are selected fir, become spread throughout entire population. Called gene flow
        
        animal and insects also contribute to gene flow
- - - - a good wy to understand natural selection is to know when it doesn't work
        
        can't work when all individuals of a population are identical #
        
        a good example is freshly planted crops of the same seed
    - - Natural selection: the most significant factor causing gene pool changes "survival of the fittest"
        
        factors that are not part of natural selection:
        
        purpose, intention, planning or voluntary decision making
        
        in order for process to happen two conditions must be met first
        
        secondary condition: progeny must differ from each other in their types of alleles
        
        population must produce more offspring than can possibly grow and survive to maturity
      - Artificial selection: process where humans purposefully change the allele frequency of a gene pool
        
        use it to enhance the plant in one form or another
        
        common use from breeders and farmers
      - accidents are events to which an organism cannot adapt
        
        ex. a large meteorite colliding with Earth
        
        if the allele just formed a new mutation, that mutation would be permanently destroyed
        
        all organisms and alleles would be destroyed
      - all genomes are subjected to mutagenic facts and mutations offer continually
        
        significance of mutation depends on population size
        
        existing alleles decrease, new alleles increase