Progress Of Cell Tissue Organs Organ System example essay topic

The tallest Biology CHAPTER 32 The tallest tree is the Redwood (Sequoia sempervirens) approx 110 m The tallest Angiosperm is the Australian Eucalyptus regnant Water Uptake and transport (Fig. 32.1) = water is essential because: transport solute, cool the body, photosynthesis and Turgor pressure Osmosis- movement of H 2) through a semi-impermeable membrane Osmotic potential (o) -depend on dissolve solute: Hi concentration means more negative o. Iso osmotic-two solution with same o; Hypo osmotic- solution that has a less negative o (more +) Turgor Pressure -hydraulic pressure result from water up take, cell turgid; analog to air pressure in a tire Water Potential -Overall tendency of a solution or cell to take up water from pure water solution. = o + P, P is positive and is measured in Mega Pascal (MPa); loss in P means the plant will wilt. MINERAL UPTAKE = Mineral and ions transported across membranes by protein: Pumps and Ion channel & Symport = Use both Facilitated (low K outside cell) and Active transport (depend on Respiration). = Plant do not have a Na / K pump but a H pump (generate membrane potential / gradient).

= Ion transport changes Electric potential of membrane (-120 mV- can be measure by electrodes) = The traffic of ions into / out of cell can be measure by Patch clamping technique. Apoplast & Symplast = Water moves into the Stele (more – ) from the cortex (less – ) from the soil (more less – ) = Mineral move by Mass flow or diffusion / Active transport (via Membrane Protein) Apoplast-movement through cell wall and intercellular space; it is continuous Symplast- movement through the cell and b / w cell via plasmodesmata; continuous but regulated = H 2 O from the Apoplast stops at the Endodermis (Stele); have Caspar ian strips -made of suberin = Strip separate Apoplast of the cortex from the Apoplast of the stele (pericycle) = Membrane protein enable enables selective mineral uptake and uptake rate. Transfer cells -in pericycle, transport minerals from cytoplasm back into the apoplast (MP / Mit, SA, rate) TRANSPORT IN XYLEM Model 1-"pumping cells's tem; ruled out by Eduard Strasburg er exp-use poison patric acid; Stop in the leaf = Exp. demonstrate: (1) pumping cell not responsible for uptake (2) leaves important (3) root not involve Model 2- "Capillary action' ruled out because capillary action cannot support 110 m tree (40 cm) Model 3- ' root pressure'-based on more – in xylem & less neg in root; support by guttation Guttation- the removal of H 2 O through the leaves under high humidity and a abundance of H 2 O in the soil = The Oozing of sap from a cut stem of Coleus when the top is remove; not enough = Root pressure changes, it either weaker or stronger but will not exceed 2 X atm pressure Evaporation-Cohesion-Tension mechanism (Fig. 32.8) (1) Evaporation of H 2 O through stomata-increase tension &make wall more – o; H 2 O enter nearest vein (2) Removal of H 2 O from leaf cause pull of water below; pull is send through the whole column (3) Column is maintain by the adhesion of water to the cell wall (glass) Summary-evaporation account for xylem transport & the resulting tension cause the cohesion Dry Air-more – o than root– less neg than sap in xylem which is less neg in leaf– less than air = Minerals dissolve in sap is transported to rest of the plant body by the phloem Evaporation-Cohesion-Tension mechanism -requires tension in column or solution of the xylem = Pressure can be measure by pressure bomb; done by Per Scho lander, Fig 32.9 = In vines there is no tension in xylem until the leaves are removed; some Plants loss tension at night TRANSPIRATION THROUGH THE STOMATA Transpiration- is the loss of water from shoot (leaf) by evaporation; also cools the cell = Loss is minimize by the cuticle; impermeable to CO 2 Stoma- composed of specialized guard cells in the epidermis which allow passage of H 2 O / CO 2 = In monocot it is associated with specialized epidermal cells; but mechanism is the same in dicot = Open by pumping of K into guard cells; stretching is regulated by Micro fibril = Pumping also allow for Cl & other organic ion uptake; maintain electrical balance or neutrality = Increase CO 2 level in spaces of leaf and – (release of ABA); blue light also reduce H pumping CAM-succulent plants-Crassulaceae-such as Kalonchoe = Have a backward stomata cycle- opens at night; leaf tissue becomes acidic (Malic / Aspartic acid = Adapted for environment devoid of water; loss of H 2 O occurs in cool environment. TRANSLOCATION = Occur in the Phloem- transport sugars, aa, minerals from leaf to root Model: bi-directional, up and down the stem or petioles (2) Arrest if tissue is damage by heating (3) Inhibited by compound that inhibit cellular respiration Pressure Flow Model- fig. 32.14-32.16 = Involve active transport of sugar into sieve tube at source (leaf) and removal at sink (stem / root ) = Sieve tubes at source cause increase in Turgor pressure; fluid is squeeze toward the Sink ends Sieve Plates- must be unclogged: it is regulated by protein which is randomly distributed (until cut) = Sugars pass from cell to cell via symport, then into the apoplast (active); likewise into sieve tube = Apoplast selectively sort out which compound is to be translocate d; Sym-Apo-Sym not universal = Sucrose is transported via secondary transport through a symport protein (H / Sugar protein) = In sink sugar are actively unloaded-maintain gradient and P in tube; Also build up sugar in seed / fruits = In some plants, Maple, sugar is stored as starch in xylem (living) of trunk / twigs ; digested in spring (syrup) CHAPTER 37 Need of one versus the many Sponges- compose of group of cell in direct contact w / environment; function independently = get nutrients from seawater; only two layers thick Multi-cellular organism- creates internal environment made of varying extracellular matrix = Cell meet need & exchange w / internal environment (IE) function independently thereof = Allow animal to occupy various habitat; Cell become specialized and efficient due to constant internal env ment = Cell become arrange in tissue system which maintain internal Environment & perform certain task = Evolution of animal physiology maintain progress of cell-tissue-organs-organ system-maintain IE. HOMEOSTASIS- maintenance of a constant composition of the IE-regardless of it continual / variable. = Enable organism to function and adapt; It is under control and regulation in response to IE / EE.

= Control and regulation requires information-Endocrine and Nervous system. Organ & organ system- many types Organ- group of tissue compose of cell with similar structure and biological function; 4 cell types = Epithelial, connective, muscles and nervous Epithelial-sheet of cell of intestine, skin and lungs; some have secretory function = mucous, digestive enzymes and sweat; some are ciliated- Olfactory system and fallopian tubes = some involve in absorption and transport; some are stratified (skin) or single layered-GUT Connective tissue- support and to reinforce other tissue. = Cell are embedded in extracellular matrix; Include ligament and tendons; lens of the eye; surround Gut = Include the Skin contain elastin protein but degrades with age; Bones-is a dense connective tissue = Include Adipose tissue- fat cells and the Component of blood Muscle tissue- include cells that cause movement of organs and limb; 3 types Skeletal-connects bone to bone; under Somatic NS control-responsible for behavior. Smooth muscles- found in internal organ (stomach); involve in the constriction of blood vessel Cardiac muscles -make up heart and pump blood Nervous tissue -enable animal to deal w / info ; 2 basic cell type Neurons-generate electrochemical signals; response to specific stimuli; = Communicate over long distances with other neurons / muscles /secretory cell; control activity of most organ Glial cell -support function of neurons; abundant in brain NERVOUS AND ENDOCRINE SYSTEM Nervous-process info and use the info to control physiology and behavior = Brain, Spinal cord and peripheral nerves-conduct signal from sensor to CNS; CNS to effector = Sensors- eye, ears, organ of taste and smell, organ of balance and orientation, touch; pain / temp /Pressure Endocrine system -process info and control function of organs via extracellular fluid (hormones) = Ductless glands-secretes hormone in blood; pancreas secretes insulin = There is a close interaction b / w NS and ES; cell in brain produce hormone that effect ES and vice versa = Messenger of ES or Endocrine Glands travels great distance to stimulate target cells SKIN, SKELETON AND MUSCLE SYSTEM Skin- the 1st line of defense against pathogens, loss of water; It's the largest organ = It a major sense organs-control rate of heat exchange (neurons); regulate body temperature. Skeleton system -support and protection; also an effector; support lever system for movement.

Muscle system -include muscles under conscious (skeletal) & unconscious control & cardiac muscles REPRODUCTIVE SYSTEM Gonads- male / female reproductive organs; include the testes / ovaries ; they produce gametes = include organ that deliver the organs; uterus-support the embryo = Mammary glands-provides nutrient for infants (breast); Gonads- contain hormone producing tissues. DIGESTIVE SYSTEM -extend from mouth to anus. = It's a continuous tubular structure– include the Gut; Gut is divided in different segment so differ function = Involve in digestion of food and absorption of nutrients; Glands-deliver digestive enzyme to the Gut = The lower Gut (intestine) reabsorb H 2 O from waste; Stores waste and eliminate them. GAS EXCHANGE SYSTEM -Trachea, Larynx, diaphragm = Also called respiratory system– provide O 2 and eliminate CO 2 = Lung- consist of many airways leading to membranous sac with large SA; the alveoli = Diaphragm? is a muscle and delivers air into and out of lungs CIRCULATORY SYSTEM = Transport O 2 from lungs to rest of body and CO 2 from tissue to the lungs = Transport nutrients from gut, deliver waste (N 2) to excretory system; regulate by hormones & remove heat Blood? contain a liquid medium the Plasma-is continuous with the extracellular fluids LYMPHATIC SYSTEM = Consist of vesicles extending through the body; do not include the heart and is not a circulatory system = Provide the extracellular fluid to circulatory system; include the immune system = Contain specialized blood cell produce in the spleen, lymphatic nodes, thymus and bone marrow EXCRETORY SYSTEM Urine-contain salt and waste product from catabolism of Amino acids and NA = Include the Kidney-control water content of body and correct salt composition of extracellular fluid = Bladder- storage of urine; Ureter- tube b / w kidney & bladder; Urethra-opening that release urine; = Skin- excrete H 2 O and salt.

Excretory system: also include the end of the digestive tract CONTROL OF REGULATION Homeostasis- depend on control / regulation of organs; organ system- depend on the need of cell of body Control-implies change in rate of a process; Regulation-a physiological concept-refer to maintain to a certain limit Regulation- requires the ability to obtain and use information. = Physiological regulation requires feedback from control system = AND how the information is obtain, process, integrate & converted by the regulatory system. To analyze a regulatory system requires US to identify the source of feedback. TEMPERATURE ANALOGY Thermostat-heating-cooling system is a regulatory system; furnace / air condition is the control system Sensors- provide the negative feedback; positive feedback amplifies an already existing response (ethylene) Feed forward information- changes the set point; it adds a clock TEMPERATURE AND LIFE = All living cell function between – 0 C and 45 C; = Chemical reaction are temperature sensitive; measure in terms of Q 10 = RT / RT-10; Q 10 = 1 not sensitive = Q 10 can be measure for single reaction or complex physiological process (O 2 consumption) = Biological process is between 2 to 3; Temperature change can be detrimental to animal ANIMAL SENSITIVITY = Some animal BT is coupled to it external temperature. Acclimalization- a physiological& biological change that animal undergo in response to seasonal change in climate = Fish-temp difference is always higher if remove from pond to lab and then to pond Metabolic compensation-readjustment of biochemical mechanism to counter effect of temp due to Acclimalization = It is not sensitive to seasonal changes but to short term fluctuation (lysozyme's-diff temp same function) MAINTAINING OPTIMAL BT Homeotherm's-animal that regulates Bt at constant levels Poikiltherms-animals whose temperature changes Hetero therms-Animal that regulates it's BT at constant level some of the time Ectotherms-depend on external source of heat to maintain BT above ET Endotherms-regulate BT by producing heat metabolically or by metabolizing active mechanism of heat loss ENDODERMS vs. ECTODERMS = Ectoderms cannot regulates it BT independently of it environment; BT will not drop below ambient temp = Endotherms regulates it Bt by altering it's rate of metabolic heat loss = Endotherms also have behavioral themoregulation; Ex. Nest construction / huddling ; widespread in Animals = Both can alter their rate of heat exchange b / w blood and environment-control the flow of blood to skin Ex, Iguana of Galop agus- control BT by blood flow to skin; slower heart rate; these are adaptive process.

= Some Ectoderms must maintain a certain temp at specific parts of it body (flight muscle, beetles, honeybee, shark) THERMOREGUALTION IN ENDOTHERMS -Fig 37.13 b, 37.14 Thermoneutral zone -narrow range of temp in which metabolic rate of Endotherms is temp independent Basal metabolic rate- is temp of metabolic rate of an animal resting in a thermoneutral zone (no digestion / reprod ) = 6 X the rate of an Ectotherms of same size; Endotherms have "leaker cells-expend E for Na / K-increase rate Thermoneutral zone Low zone-high rate to maintain BT due to heat loss; At maximum rate BT decline (dies). At high extreme-expand heat to cool the body (pants / sweat ); at maximum rate / High temp- BT increases (dies) Methods- mammals-either shiver or sweat; birds-shiver (skeletal muscle ATP– heat) = Brown fats– Non-shivering; use tissue rich in Mit / blood supply and Thermogenic. COLD vs. HOT- Fig. 37.21 = Cold climate Endotherms reduce heat by: smaller SA, round shape, shorter appendages fat, thicker fur THERMAL INSULATION AND RATE OF HEAT LOSS = Thermal energy is release by body to it's environment = Muscle contraction or change blood flow to skin; WOLF-constrict Blood vessel in its feet at above 0 C = Elephant, Rhinos, water Buffaloes have thick layer of fur; so they wallow in water = Sweating, panting are last resort use bu animals in hot climate or habitat (H 2 O evaporate quickly) THE VERTEBRATE THERMOSTAT- Fig 37.22/37.23 = All animals that thermo regulate must have a regulatory system; Info get from Hypothalamus-integration center In Humans: If glands is cool BT rises (constriction of Blood vessels and increase rate); Hypo temp is – feedback = Amount of increase in heat is proportional to how much the glands is cooled below the Set point. = Hypothalamus receive info from sensor in skin to shift the set point for responses; Higher when skin is cold FEVER Fever is a rise in BT in response to substance called Pyrogen's; heat production above set point cause chills, shiver = Macrophages attack antigen then secretes interleukin's; Interleukin stimulate prostaglandin and raise the set point ANIMAL AND THEIR THERMOSTAT Hypothermia- condition in which BT is below normal (starvation, illness, anesthetic) = Can cause unconsciousness, weaker contraction, nerve impulse, slow metabolism, cell damage / O 2) Torpor-condition in which an animal lowers its BT during the time of inactivity (Air temp, mice, hummingbird) = Willow tit lowers it Bt at night; the brain of the willow is it's integrated center for the thermostat. Hibernation -is the hyptherming to low temp for days of weeks; = It assures maximum energy conservation; BT is maintain at freezing pt.

= Metabolic rate 1/5 basal (Ex bats, bears, squirrel, poor will); occur when temp is low and food scarce = Control by biological clock (Circ annual rhythm); rhythm cycle of squirrel include active season; Hib-spring to fall Active season -Animal breed, raise young, prepare nest, fatten bodies and store food Hibernation season -occur in bouts; lose body weight; at end sex organs become functional CHAPTER 44 MUSCLE CONTRACTION: Actin / myosin interaction Effectors-adaptation in response to info that is sensed, integrated & transmitted by its neuron & endocrine = Muscle contraction is the most important effector mechanism in animal in response to Environment cues = All physiological and behavioral response depend on muscle cells Muscle Cells- have high density microfilament and myosin = Account for movement in earthworm, jelly fish, limb movement in Anthropoids / vertebrates = Found in blood vessel, gut, bladder and heart or where ever tissue contracts = Smooth, Skeleton and Cardiac Smooth Muscles = Provides contraction for internal organs under control of autonomic Nervous System (involuntary control) = Move food through digestive tracts; involve in blood flow and empties the urinary bladder = Simplest cell- long spindle-shaped w / single nuclei; actin / myosin not regularly arrange In digestive tracts: arrange as sheet of attach by Gap junction (electrical conduction) = Stretching the tract depolarize it's membrane potential- result in contraction; longer contract more stretch SKELETAL MUSCLES -strained muscle = Control all voluntary movement: running, playing the piano, generate movement of breathing = Highly regular arrangement of Actin / myosin ; Muscle fiber are large & multi-nucleated = Biceps compose of muscle fibers bundled together by connective tissues (Fig. 44.1) Muscle fibers- compose of myofibrils Myofibrils- are bundles of contractile filament; each thick filament is surrounded by thin filament = Band pattern of myofibrils due to its repeated units called Sarco meres-the unit of contraction. Contraction = The I-band- the region b / w A-bands and the Z-line; contain only thin filament (light) = A-band region of thick filament (center); H-zone- M-line and region where thick / thin do not overlap = Sliding of Filament theory-propose by Andrew and Hugh Huxley = Shorten of the H-zone and I-band; Z-line moves towards the A-band as if Actin is slide over myosin MYOSIN- made of 2 polypeptide chain coils ending in a globular head (contain ATPase) = Myosin filament compose of myosin molecules arranged parallel w / the head protruding MICROFILAMENT- consist of helically arranged polypeptide chain consisting of G-actin globular protein = Contain tropomyosin (2 chain) twist around Actin helix & Troponin- binds Ca, Actin, Tropomyosin Interaction = Head of myosin filament interact w / Actin cause 5-10 nm shift relative to the other; ATP return the system Rigor mortis -stiffness on muscle after death; no ATP no release of filament = Muscle at different part of body soften at different times (lose integrity); estimate time of death Interaction and Calcium Motor Unit- all fibers innervated by a single motor neuron which triggers it to contract (1) Contraction is initiated by nerve impulses at neuromuscular junction; receptor binding of molecules (2) Molecules is release in the synapsis by neurons via action potential (open channel) along it (3) Polarization of Plasma membrane of fibers send message throughout fibers & T-tubule system (4) Ca is pump into Sarcoplasmic Reticulum (SR) from Sarcoplasm (contact with T-tubule system) (5) Hi conc of Ca in SR is release into Sarcoplasm by opening of channels via the action potential (6) Binding of Ca to Troponin induce change in Tropomyosin which expose Actin-myosin bind site SMOOTH MUSCLE CONTRACTION = Contain no Troponin-Tropomyosin mechanism but use Ca; stimulated by Ca in cytoplasm = Stimulated by stretching, hormones level, action potential; Ca binds to Calmodulin protein Ca-Calmodulin complex- activate protein Kinase; Phosphorylation activate actin / myosin interaction = Re polarization of muscle fibers occurs through the pumping of Ca back into the SR (muscle relaxes) Muscle twitches In skeleton Muscle- the spread of impulse along fibers that cause a minimum contraction, a twitch = Twitch measured in terms of tension or the force it generates = If the twitch is generated over an adequate time period – ALL-or-None response or discrete twitch = Rapid firing cause summation of twitches; tension increase and contraction is continuous = Hi level of stimulation result in Tetanus- maximum contraction (no Ca from SR to S) Strength of the contraction depend on: (1) ' of motor neuron firing (2) rate of firing = some muscle have low level of tension, called Tonus when body at rest; neck, trunk and limb = Muscle Tonus arise from activity of many motor units; ? time in contract &? time relax; regulate by NS Muscle fibers, Aerobic condition and strength = A single muscles may contain different fibers types: SLOW and FAST-Twitch Slow-twitch- called Red muscle; contain many myoglobin, glycogen, fats and mitochondria & well supported blood vessels = They are resistant to fatigue so make of low tension fibers; found in most athletes Fast-twitch- called white muscle; fatigue rapidly; high myosin-ATP activity; sprinters and weightlifters. CARDIAC MUSCLES = Cell appear striated and are branched; so resistance to tear and high pressure = Also contain intercalated disc-mechanical adhesion and arrangement b / w cells (gap junction) = Conduct electricity due to low resistance to ion; they depolarize rapidly = Also contain special cell that are pacemakers (sinus node); so heartbeat is myogenic-beat it's own = Rate pacemaker cell is modified by Autonomic NS; not responsible for its continuous heart beat rhythm SKELETAL SYSTEM = Provide rigid support and attachment of muscles; 3 type of Skeleton; Hydrostatic, exo & endoskeleton Hydrostatic Skeleton = Found in cnidarian (sea anemone), annelids (earthworms) and soft-bodied invertebrates. = Contain incompressible fluid enclosed in a cavity surrounded muscles Movement: Usually involves muscle arrange longitudinal (retract) and circular (extension, fig. 44.13) = Alteration of contraction cause movement; Also found in Squid and Octopus.

Exoskeleton Exoskeleton- is a harden outer surface to which internal muscles are attach. Joints move relative to other Mollusk-shell grow with animal (note rings); Snails-shell made w / CaCO 3 and protein = Molluscan shell use for protein: Soft part of body is for Locomotion (hydrostatic skeleton) Antropod- (soft-shell crab) made of cuticle but not at joints; will not grow with animal; Crustacean-CaCo 3 Cuticle- 2 layers: Outer-the Epi cuticle is thin prevent drying out; Inner-Endo cuticle, thicken, Protein chitin Vertebrate Skeleton = Compose of bones connected by various joints; 206 bones; rod like, plate like and tube like = Divide into 2-skeleton-Axial (Ribs, sternum, skull and vertebral column and Appendicular skeleton- bones of the Arm, leg, feet & hands, pectoral girdle. = Endoskeleton- grows with organism; contain 2 kind of connective tissue: Cartilage and Bones CONNECTIVE TISSUE CELLS- large matrix of protein (collagen) and polysaccharides Cartilage- found where stiffness and resiliency is required (surface of joints) = Found in Larynx, nose, ears, shark and rays and embryonic skeleton during development Bones-mostly Collagen and CaPO 4; reservoir for Ca for the body; In equal with Ca in the Matrix = Under calcitonin and parathyroid control = Cell of Bones– Osteoblast, Osteocytes, Osteoclast Osteoblast-lay down new matrix on bone surface until cavitize (lacunae) in the bone. Osteocytes-Cavitize osteoblast cells; remain in contact by communicating Osteoclasts- erode and reabsorb bones; derive from WBC producing cells; for cavity and tunnel in bones = They proceed osteoblast so involve in remodeling BONES and CONNECTIVE Tissues– 2 types Membranous bones- form on scaffolding of connective tissue membrane; outer bone of skull Cartilage bone- form on cartilaginous structures until gradually ossified (limb); can grow -center outward Compact-good for compression / bending ; called Haversian bone in mammal (made of unit of Haversian sys) Cancellous bones- spongy bone; can stand compressive force BONES And JOINTS = Muscle work as antagonist pairs; contract and relax; Flexor-flex joints; Extensor- extend joint Ligament- bands of connective tissue that hold joint bones together Tenons- Connective tissue that attach muscles to bones; may span the joint Quadriceps (in knee jerk reflex) Types of joint- Hinge, ball-in the socket, Saddle joints, Pivotal joint, Ellipsoid joint, plane joint Hinge- knee; allow no rotation & flex in one direction; Saddle-b / w carpel bones; Plane -b / w tarsal bone Ellipsoid-b / w phalanges; Ball-in-socket-at hips; allow movement in most direction Pivotal- b / w 2 bones of the forearms at elbow; allow radius to rotate when wrist move side to side. LEVER SYSTEM- demonstrate the translation of force into fast movement or over short distance. Ratio = load arm / power arm; Arm-small ratio; much for over short distance: LEG-large; less force / short Dist EFFECTORS of Animal kingdom = Muscle are effector; not all effector are muscles; Function- as specialize for other function = Defense, communication, capture and avoidance Nematocyst-Hydra and Portuguese-man-of-war = Coiled structure produce by cell in tentacle; Hydra-contain a spine shape trigger projectile to capture prey = Once trigger it entangle and penetrate the prey Chromatophore's-pigment containing cell; under NS / Hormonal control; In Squids and Chameleon = Can be use for mating or for terrestrial rivaling in some species; There are 3 types Fixed cell- contain pigment granules-move by microfilament; high concentration means animal is pale Some capable of Amoeboid movement; Cephalopods-muscle contractions GLANDS- produce chemical involve in communication, defense or to capture prey Poison glands -snakes, frogs, fish, spiders; Dendrotoxin produce from skin of frog (use by arrow of tribe) Venom- bungarotoxin, inactivate acetylcholine receptor Puffer fish-tetrodotoxin, blocks Na / voltage gated channel; Mollusk-Conotoxin- interferes with Ca-channel NON-poisonous Glands = Mercaptan release by skunk; Pheromone-sex hormone; use as communication in some animals / protist = Gland are also involve in digestion (salivary) and heat regulation (sweat glands) Electric Organs = Electric eel (600 volts) and Torpedo ray and Catfish = The electric field is use to sense environmental cues, communication, capture prey; evolve from muscles CHAPTER 36 Plants reproduce both sexually and asexually; both are important in agriculture Grain crops such as: millet, rice, cereal & wheat all grow from seed (sexual).

The nasal orange however grows from a seedless orange seed (asexual). SEXUAL REPRODUCTION– genetic diversity = Meiosis and mating shuffles genes in a population; this produce diversity = Diversity serve as environmental changes or expansion into a new environment. Flower- a modified leaf Carpel-stigma, style, ovary; Stamen- anthers & filament; petals and sepals; calyx- collection of sepals. Carpel- bears the megasporangia (ovary and integument) – which produce the megasporangium Corolla-is collection of petals; Sepals- series of petals and sepals = Flowers is where alternation of generation lives (gametophytes, Fig 36.1) Gametophyte- a gamete producing generation that develop from haploid spores or sporangia.

Megasporangia- Produce the female gametophyte or megagametophyte or embryo sac. Microsporangia– produce the male gametophyte or micro gametophyte or pollen grain. Mega sporocyte? in megasporangia (ovule); produce 4 megaspores (meiosis); one spore survive. = The megaspore undergo 3 mitotic division in a single cell (3 top, 3 bottom, 2 middle); megagametophyte = cell wall formation lead to 7-celled gametophyte with 8 nuclei = 3 cell at micropyle-1 egg/2 synergic cells; 3 at top-called antipodal; 2 center-produce endosperm. The anther's (microsporangia) micro sporocyte produce microspores by meiosis-divide once then release. POLLINATION- transfer of pollen from anther to stigma.

= In gymnosperm / angiosperm the sperm travels in pollen grains. 2 types; self-pollination (legumes, peas) and cross- pollination (wind, insect, animals and water). In wind pollinated flowers the stigma is sticky or feather like.