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Today’s Plan: 4/12/10 Bellwork: Set up lab(15 mins) Finish AP Lab 11 (45 mins) Behavior notes (the rest of class) Today’s Plan: 4/13/2010 Bellwork: Finish Plant Behaviors (15 mins) Symmetry and tissue layers stations (45 mins) Animal Behavior notes (the rest of class) Pack/Wrap-up (last few mins of class) Today’s Plan: 4/14/2010 Bellwork: Go over plans (10 mins) Finish Symmetry and tissues(40 mins) Notes, continued (the rest of class) Today’s Plan: 4/19/2010 Check-in with animals progress (5 mins) Finish Behavior notes (15 mins) Finish invertebrates/begin vertebrates? (40 mins) Notes (the rest of class) Pack/Wrap-up (last few mins of class) Today’s Plan: 11/12/09 Finish Behavior notes (20 mins) Finish Vertebrates (40 mins) Animals Notes (the rest of class) Today’s Plan: 4/20/09 Bellwork: Invertebrate activities (20 mins) Vertebrate activities (40 mins) Notes (the rest of class) Today’s Plan: 4/21/09 Finish Beh. Notes (15 mins) Finish Vertebrates and chart (45 mins) Go over animals (the rest of class) Plant Regulation and Behavior Plants use hormones to regulate function, since they lack a nervous system There are a variety of hormones to control every plant response or to regulate all of the plant’s functions Growth-auxin, cytokinins, and gibberellins Apical dominance-cytokinins Cell division and differentiation-cytokinins Germination and fruit growth-giberellins Leaf dropping (abscission)-abscissic acid Fruit ripening-ethylene Figure 39-33-Table 39-2-1 Figure 39-33-Table 39-2-2 Figure 39-33-Table 39-2-3 Figure 39-26 PLANT TISSUE CULTURE 1. Start with piece of plant tissue. 2. Callus grows. 3. Roots form. 4. Shoots form. Figure 39-33 LEAF SENESCENCE AND ABSCISSION Senescent leaf Healthy leaf Age, drought, temperature, day length, etc. reduce auxin production from leaf Abscised leaf A protective layer has formed to seal stem where leaf was attached Abscission zone 1. High auxin: Cells in abscission 2. Low auxin: Cells in abscission 3. Leaf detaches at the zone are insensitive to ethylene. Leaf functions normally. zone become more sensitive to ethylene, leading to leaf senescence. abscission zone. Figure 39-32 Apical Dominance Controlled by an interaction of auxin and cytokinin Auxin produced at the terminal bud supresses the axillary buds, but decreases in concentration as it moves down the shoot. Cytokinins coming up from the root counteract the auxins in the stem, causing the lower axillary buds to develop Figure 39-23 Apical meristem intact Apical meristem cut off Lateral shoots Figure 39-24 Gradient of auxin concentration Apical end (toward shoot) 2H+ Auxin Auxin Cotransporters at top of cells bring auxin in Some auxin molecules are destroyed by enzymes as they travel down Carrier proteins at bottom of cells send auxin out Basal end (toward root) How do hormones work? Usually, there’s a signal transduction pathway involved Figure 39-1 STEPS IN INFORMATION PROCESSING External stimulus on receptor cell Internal signal 1. Receptor cell perceives external stimulus and transduces the information to an internal signal. 2. A hormone Cell-cell signal (cell-cell signal) released by the receptor cell travels throughout the body. 3. Receptor cells Internal signal receive the hormonal (cell-cell) signal, transduce it to an internal signal, and change activity. SIGNAL TRANSDUCTION 1. Signal Cell wall 2. Receptor protein changes in response to signal. Cell membrane ATP ADP ATP ADP Phosphorylation cascade Figure 39-2 3. Receptor or associated protein catalyzes phosphorylation reaction. 4. Phosphorylated protein triggers phosphorylation cascade (left)… ATP …OR release of second messenger (right). ADP Vacuole ATP Second messenger ADP 5. Phosphorylated proteins or second messenger initiate response. OR OR DNA 6. Activate or repress transcription. 6. Activate or repress translation. Nucleus 6. Change ion flow through channel or pump. Tropism Recall from Biology that a tropism in plants is growth in response to a stimulus Phototropism-growth toward light (auxins) Gravitromism-growth in response to gravity (amyloplasts and auxin) Thigmotropism-growth in response to touch Thigmomorphogenesis-stunted growth in plants that are mechanically stimulated (due to ethylene production) Figure 39-8 The phototropic signal is a chemical. Light Permeable agar: Impermeable mica: Shoot bends toward light No bending Chemical diffuses through agar The hormone can cause bending in darkness. Allow time for hormone to diffuse into agar block. Offset blocks cause bending of shoots not exposed to light The hormone causes bending by elongating cells. Cells on the shaded side elongate in response to the hormone (red dots) Figure 39-16 Roots grow down. Shoots grow up (or out, in some species). Figure 39-17 Root tips have a protective cap. Cap Gravity-sensing cells are in the center of the cap. Figure 39-18 Gravity Cell in root tip (or shoot) Amyloplasts are pulled to bottom of cells by gravity Activated pressure receptors AUXIN AS THE GRAVITROPIC SIGNAL Auxin distribution Auxin Gravity Figure 39-19 1. Normal distribution of auxin in vertical root prior to disturbance. 2. Root tip moved into horizontal position. 3. Gravity-sensing cells actively redistribute the auxin–more goes to bottom side. 4. Asymmetric auxin distribution inhibits cell growth on lower side and stimulates growth on upper side, leading to bending. Figure 39-21 Tendril Figure 39-27 Normal plant Dwarfed plant Plant movements Rapid leaf movements-sensitive plant withers when touched, b/c of an electric impulse (like that of a muscle contraction), causing rapid loss of turgor pressure Sleep movements-plants lower their leaves at night in response to different turgor pressure in cells Photoperiodism This is a plant’s response to a seasonal photoperiod (number of hours of light) Ex: Flowering Short-day plants-need a long night (less time in the light) and flower in fall or winter Long-day plants-need a short night (more time in the light) and flower in spring and summer Day neutral plants-unaffected by photoperiod Critical Night Length-flashing light during the dark period can throw off a plant’s ability to flower What controls flowering internally? Buds produce flowers, but photoperiod is detected by the leaves (plants with leaves removed can’t flower) A bud’s meristem must transition from vegetative growth to flowering Figure 39-13 How do plants respond to differences in day length? How do plants respond to nights interrupted by light? Phytochrome This is the pigment that actually detects the amount of light striking the plant Has 2 forms: Red and Far Red which are isomers of one another. Plants synthesize Pr, but sunlight converts it to Pfr At night, the Pfr reverts back to Pr, so the ratio of Pr to Pfr “tells” the plant how much sunlight it has absorbed The only thing is, the conversion of fr to r takes place in a few hours, so it doesn’t tell the plant how much darkness it has had. There is another internal circadian rhythm that measures the amount of dark based on when the sun sets and when it rises (informed by phytochrome) Figure 39-15 Phytochrome (Pr conformation) Red light (sunlight) Phytochrome (Pfr conformation) Red light: cis to trans shape change Far-red light (shade light) Photoreversible cis Isomer Far-red light: trans to cis shape change trans Isomer Figure 39-14 Hours Light flash Critical night length Long-day (short-night) plant Short-day (long-night) plant Figure 39-12 Ungerminated lettuce seed Red light (sunlight) 660 nm Inhibits germination Phytochrome (Pr conformation) Germinated lettuce seed Far-red light (shade light) 735 nm Shape change Shape change Stimulates germination Phytochrome (Pfr conformation) Plant Responses to Environmental Stress Water Stress-Stomates close b/c of a buildup of ABA Oxygen Deprivation-Plants form air tubes in the root if their soil is too wet Salt Stress-plants can produce compatible solutes in their cells to keep from losing water Heat Stress-transpiration does evaporative cooling, plus they can produce heat-shock proteins that can scaffold the other proteins in the cell to keep them from denaturing Cold Stress-plants can alter the lipid composition of their plasma membranes, and alter their solute composition to keep the cytosol from freezing Herbivores-physical and chemical defenses Physical-thorns Chemical-toxins or bad-tasing chemicals Recruitment-plants release chemicals that attract predators of herbivores (wasps vs. caterpillars) Figure 39-31 STOMATA OPEN IN RESPONSE TO BLUE LIGHT. Blue light strikes photoreceptor. STOMATA CLOSE IN RESPONSE TO ABA. ABA binds to receptors on guard cells. 1. Pumping by H+-ATPases 1. Pumping by H+-ATPases increases. Protons leave guard cells. stops. Outward-directed Cl channels open. Cl exits along electrochemical gradient. 2. K+ and Cl enter cells 2. Change in membrane along electrochemical gradients via inwarddirected K+ channels and H+/Cl cotransporter. potential open outward- 3. H2O follows by osmosis. 3. H2O follows by osmosis. 4. Cells swell. Pore opens. 4. Cells shrink. Pore closes. directed K+ channels. K+ exits along electrochemical gradient. Figure 39-39 Herbivore Wasp larvae emerging from devoured caterpillar Plant Defenses against pathogens First line of defense is the epidermis and cutin, however openings, like the stomata invite infections In general, pathogens gain enough from plants to benefit, but try not to severely damage or kill the plant Gene-for-gene recognition gives plants specific resistance to disease Hypersensitive Response(HR)-is produced when the plant is resistant to the pathogen. The plant produces more phytoalexins and PRs, and the plant can “seal” against the pathogen. Pland has r (resistance) genes, and the pathogen has avr(avirulance) genes. If any one of the plant’s r genes is dominant and corresponds to a dominant avr in the pathogen, the plant is resistant. If the plant is not resistant to the pathogen, it produces phytoalexins (antimicrobial agents) and PR proteins (pathogenesis-related) that can attack the infectious agent When the plants seal an infected area, they destroy themselves and a lesion forms Systematic acquired resistance (SAR)-occurs when the plant releases alarm hormones from the site of the HR response, alerting the rest of the plant of the infection. The other cells then release phytialexins and PRs Figure 39-34 GENE-FOR-GENE HYPOTHESIS Virus Bacterium Fungus 1. Pathogens (virus, bacterium, or fungus) enter plant cell via wound or connection with infected cell. 2. Pathogens release avr gene products and other molecules. 3. R gene products from host bind to avr gene products. 4. Binding activates R gene products and triggers protective hypersensitive response (HR). When R and avr gene products do not match, no HR occurs and plant succumbs to disease. Figure 39-35 Gene-for-gene interactions in a heterozygous plant R gene 1 R gene 2 R gene 3 R gene 4 . . . Gene-for-gene interactions in a homozygous plant R gene 1 R gene 2 R gene 3 R gene 4 . . . Figure 39-36 HYPERSENSITIVE RESPONSE (HR) Dead pathogens Pathogen R avr R avr Dead host (no more food for pathogens) 1. An R gene product binds to an avr 2. The HR includes the production of nitric 3. The HR results in the reinforcement of protein from a pathogen, triggering the hypersensitive response (HR). oxide (NO), reactive oxygen intermediates (ROIs), superoxide ions (O2–), and phytoalexins. cell walls, the suicide of infected cells, and the extermination of invading pathogens. Figure 39-39-Table 39-3-1 Figure 39-39-Table 39-3-2 Animal Behavior Nature or Nurture? Most scientists think it’s about 60% genetic, 40% environment Taxis-Response to a stimulus Reflex-controlled by a reflex arc and is not under brain control Instincts-also called innate behaviors that are thought to be genetically programmed (although may not be solely due to genes). The broader definition states that these are developmentally fixed behaviors that don’t vary between individuals of a species General types Cause of behavior Proximate causes-things that are happening NOW (ex: stimuli, mechanics of the action, etc)-these tend to be how questions Ultimate causes-the evolutionary reasons for behavior (ex: this behavior first appeared in an ancestral species)-these tend to be why questions Figure 51-2 Yawning Innate: no modification through learning Smiling Highly stereotyped Fixed: little variation Highly flexible Condition dependent Language acquisition Originates and is modified through learning Ethology-The classical study of animal behavior Understanding behavior means understanding the answers to the following: What stimulus elicits the behavior, and what physiologic mechanism controls the response? How does the animal’s experience during growth and development influence the response? How does the behavior aid survival and reproduction? What is the behavior’s evolutionary history? Fixed Action Pattern (FAP)-sequence of behaviors that once triggered is done to completion. The trigger is called a sign stimulus (ex: moths drop when certain ultrasonic signals occur) FAPs tend to be simple reactions to limited stimuli Ex: stickleback fish attacking any red-bottomed object Figure 51-14 1 2 1 3 2 When the bat is here (position 1)… Search …the insect is here (position 1) Approach 3 Power dive Terminal 4 Pulses of high-pitched shouts from bat Behavioral Ecology This is based on the premise that animals behave to maximize their evolutionary fitness and is the modern form of ethology. Cost/Benefit (TANSTAAFL) Foraging Behavior-most foragers are generalists but don’t randomly choose food. In stead, they form a search image of specific characteristics they’re looking for. When a particular food is scarce, animals can switch search images There are trade-offs in order to ensure optimal foraging, however Distance of food vs. size of food Energy obtained by food vs. energy used to obtain the food Figure 51-3 White-fronted bee-eaters are native to East Africa. Birds fly from their nesting colony to a foraging area, which might be close to the colony or far away Foraging behavior depends on distance traveled. Other examples of cost/benefit Parental investment-amount of energy invested in existing offspring at the expense of having additional offspring Mate choice-involves competition between males, female choice and possibly putting up with different mating schemes Monogamy Polygamy Promiscuity/cheating Game Theory applications-behaviors can often be explained using game theory Paper, rock, scissors and throat color of the sideblotched lizard. Orange=aggressive and defend large territories, Blue=small territories, yellow=sneaky Figure 51-19 Territorial male Female Female-mimic male Other behviors studied Migration-how do animals navigate? Rhythmic Behaviors- Circadian Rhythms-24 hour sleep/wake cycles circannual Rhythms-hibernation and estivation cycles Signals and Communication-usually a combination of gestures, postures, calls, touches, and sometimes pheromones (chemicals that animals emit which stimulate a response) Ex: honeybee dances-tell the hive where to find nectar Figure 51-16 The round dance The waggle dance Other bee workers follow the progress of the dance by touching the displaying individual Figure 51-17 Straight runs down the wall of the hive indicate that food is opposite the direction of the Sun. Downward waggle dance on honeycomb Sun Straight runs to the right indicate that food is 90 to the right of the Sun. Sun Sideways waggle dance on honeycomb Beehive Beehive 90 Down Down 100+ m Food source away from Sun 100+ m Food source at right angle to Sun Learning This is an experienced-based behavior modification Learning can affect developmentally fixed behavior, but not vice-versa There’s often a distinction between maturation and learning (birds can “learn” to fly, even if in isolation) Types of learning Habituation-getting used to a repeated stimulus Imprinting-time sensitive learning during a critical period that is irreversable (organism learns who their parents are and therefore mimics them)-Konrad Lorenz Spatial Learning-Tinbergen’s wasp study Insight-performing a behavior correctly without any prior experience, this is different from observational learning Operant conditioning-trial and error learning (rats in mazes)-B.F. Skinner Classical Conditioning-associative learning (Pavlov’s dogs) Figure 51-7 Learning Leads to. . . Warning coloration-a predator only has to know 1 warning color pattern in order to avoid danger Mimicry-animals looking dangerous by mimicking others’ warning coloration. Sometimes they’re also dangerous, sometimes they’re not. Play-practice aggression and social behavior Cognition?-Some animals have problemsolving abilities that lead to things like tool use Figure 51-18c This butterfly looks like a bad-tasting species but actually tastes good What about the genetics of behavior? Cross-fostering studies are helpful in understanding the extent to which behavior can be modified by environment Scientists have also looked at organisms reared in isolation that exhibit behaviors perfectly, indicating genetic regulation of behavior Inclusive fitness and Social Behaviors Why would an organism do an altruistic (not for it’s own fitness) act? Ex: prarie dogs and alarm calls, bees not mating, etc Kin selection-ensuring that your close relatives reproduce ensures your genome’s survival (inclusive fitness) Hamilton’s rule=rB>C r=coefficient of relatedness B=benefit C=Cost Figure 51-21 What is the r between half-siblings? Probability that mother transmits a particular allele to son is 1/2 Probability that mother transmits a particular allele to daughter is 1/2 What is the probability that half-siblings inherit the same allele from their common parent? Answer: r between half-siblings = 1/2 1/2 = 1/4 What is the r between full siblings? Probability that father transmits a particular allele to daughter is 1/2 (same for both arrows) Probability that mother transmits a particular allele to daughter is 1/2 (same for both arrows) What is the probability that full siblings inherit the same allele from their father or their mother? Answer: Probability that they inherit same allele from father = 1/2 1/2 = 1/4 Probability that they inherit same allele from mother = 1/2 1/2 = 1/4 Overall probability that they inherit the same allele = 1/4 + 1/4 = 1/2 r between full siblings = 1/2 Social Structures Eusociality-organisms like termites, ants, and bees that are haplodiploid Females arise from fertilized eggs Males arise from unfertilized eggs Hierarchies-based on dominance Territorial behavior-reinforced by agonistic (aggressive) behaviors Reciprocal altruism