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Chapter 7 Energy relations Energy sources and trophic biology: light, organic molecules, or inorganic molecules.

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Presentation on theme: "Chapter 7 Energy relations Energy sources and trophic biology: light, organic molecules, or inorganic molecules."— Presentation transcript:

1 Chapter 7 Energy relations Energy sources and trophic biology: light, organic molecules, or inorganic molecules

2 Announcements? Meetings?

3 Photosynthesis = autotrophic –Plants, bacteria, protists Energy sources and trophic biology

4 Chemosynthesis = autotrophic –Bacteria Energy sources and trophic biology

5 Consume organic matter = heterotrophic –Bacteria, fungi, protists, animals, plants Energy sources and trophic biology

6 Trophic diversity across biological kingdoms Figure 7.2

7 3 biochemical pathways for photosynthesis: C 3 In dry environments: –C 4 –CAM

8 Cool/moist, low light environ Energy efficient Less efficient water use Less efficient CO 2 uptake Different photosynthesis types in different environments - C 3

9 Hot/dry, high light environ Less energy efficient More efficient water use More efficient CO 2 uptake Different photosynthesis types in different environments - C 4

10 Desert - succulents Less energy efficient Most efficient water use Efficient CO 2 uptake at NIGHT Different photosynthesis types in different environments - CAM

11 Energy Relations In Plants ( All measured by CO 2 flux) Gross Photosynthesis (P gross ) –Total amount of CO 2 fixed into glucose Respiration (R) –Total amount of glucose utilized for energy Net Photosynthesis (P net ) –P gross - R

12 Generalized Light Response Curve Irradiance P net (= P gross - R) Compensation Point Saturation Point

13 Contrasting photosynthetic response curves Figure 7.21

14 Light response curve: 1 = range of irradiance where P limited by low light

15 Light response curve: 2 = optimum irradiance (max P net )

16 Light response curve: 3 = range of irradiance where P limited by high light; breaks down photosynthetic apparatus faster than repaired

17 Light Response Curves Irradiance P net (= P gross - R) C4 Plant Species Sugar Cane Sorghum Corn C3 Plant Species Trees Wheat Algae C3 Species Have Higher P net in Low Light

18 Light response curve for different species

19 Generalized Nutrient Response Curve Growth Rate Nutrient Concentration >>>Toxicity >>>> Saturation Optimum

20 Nutrient Response Curves Growth Rate Nutrient Concentration Macro- Nutrient Micro- Nutrient C O H P K N S Mg Ca Fe Mn Zn Cu Mo B Cl. Required in large quantities Rarely toxic at concentrations that occur in Nature Required in small quantities Become toxic at higher concentrations

21 Energy/nutrients usually in limited supply Environment-plant relations: –Photosynthesis only with appropriate T, light, water, nutrients (based on climate/soil)

22 Energy/nutrients usually limited supply Plant-Herbivore relations –Plants are numerous –Easy to find, catch –Low nutritional value –Available seasonally

23 Energy/nutrients usually limited supply Plant-Herbivore relations –Plants use physical and chemical defenses Thorns Toxins Digestion-reducing compounds

24 Energy/nutrients usually limited supply Predator-Prey relations: –Prey animals less numerous than plants –difficult to find, catch –Higher nutritional value

25 Energy/nutrients usually limited supply Predator-Prey relations: –Evolution of defenses by plants and prey animals –NS pressure on herbivores/predators to evolve alternative methods

26 Energy/nutrients usually limited supply Detritivores: –Majority of food plant material

27 Predation 1 search 2 recognition 3 catching 4 consumption

28 Table of adaptations Pred activityPred activity SearchingSearching Pred adaptationPred adaptation Sensory acuitySensory acuity Search where prey are abundantSearch where prey are abundant Search imageSearch image Prey counter-adaptationPrey counter-adaptation Improved sensory acuityImproved sensory acuity Space outSpace out PolymorphismPolymorphism

29 Table cont. Pred activity Recognition of prey Pred adaptation Learning Prey counter- adaptation Warning signals, mimicry

30 Pred activity Catching Pred adaptation Improved motor skills Weapons of offense Prey counter-adaptation Improved motor skills, startle responses, aggregation formation Weapons of defense Table cont.

31 Pred activity Handling prey Pred adaptation Subduing skills Detoxification ability Prey counter-adaptation Active defense, tough integument, autotomy Toxins

32 Anglerfish: Frogfish: Cryptic against rocky background. Lure to attract prey.

33 Harris Hawk To detect small prey, extremely good eyesight. For capturing prey, has sharp beak and talons.

34 SEA ANEMONES - poisonous tentacles. Counter-adaptation, CLOWNFISH coat themselves with chemical inhibitor - prevents anemone stings, avoid predation from anemone and other fish.

35 FLOUNDER Lies on one side of its body - prevents shadow. Chromatophores modify color to match background. Throws sand on the top of their flattened body to increase concealment.

36 What do these BUTTERFLIES mimic?

37 Some INSECTS resemble twigs in physical structure and behavior. They can branch off a limb and remain motionless.

38 AUSTRALIANTAWNYFROGMOUTH Resembles part of the tree in which it rests. This bird is active at night and remains motionless during dayight hours.

39 GRAY TREEFROGS occur as two different color morphs within the same population: a brown morph and a green morph.

40 Predators generally avoid snakes with a bright banding pattern of black, yellow, and red. ~ 70 spp. of New World snakes have this "coral" type of banding. EASTERN CORAL SNAKE is highly venomous

41 Warning signals need not always be visual. RATTLESNAKES possess a highly venomous bite and give a warning noise with their rattle.

42 Warning signals can be olfactory: SKUNKS- warning coloration and bad odor warn predators. Spray temporarily blinds close predators; offensive odor lingers long after discharge.

43 MONARCH BUTTERFLY feeds as larva on milkweed plants - contain toxins. Toxins are sequestered in tissues of adult. Distinctive colors of adult Monarch warns birds not to eat them.

44 VICEROY (left) closely resembles Monarchs. Although not distasteful, birds avoid Viceroy.

45 Katydids employ two types of defense. First, coloration resembles leaves - crypsis decreases chances of detection. If detected, second line of defense decreases probability of being captured - it hops away.

46 PEACOCK BUTTERFLY from Ireland has spots resembling eyes. These "eyes" frighten away insectivorous birds.

47 Squids deter predation by forming a group. Group formation may decrease per capita predation risk in number of ways: selfish herd behavior, confusion effects, or by having more individuals on look out for approaching predator. This may explain why large ungulates travel in herds.

48 ELK have keen sense of smell, good hearing, and are swift runners to avoid most predators. If trapped in deep snow, antlers are a match for most predators.

49 Turtles have tough integument which is virtually impenetrable. BOX TURTLES have broad hinge across plastron, allows them to completely close shell so tightly - not even a knifeblade can be inserted.

50 Six-lined Racerunner has a bright colored tail that distracts predators from its head. When caught, the tail breaks off allowing the lizard to escape = AUTOTOMY.

51 HEDGEHOGS are covered with sharp spines similar to the porcupine. When attacked, they curl up into a ball exposing a sphere of spines.

52 LIONFISH have long, poisonous spines that are used as a defense against predators.

53 POISON ARROW FROGS of C. and S. America produce mucous covering - one of most potent natural poisons known. Mucous used by native people to poison arrow points. Frog has warning coloration.

54 Counter-adaptations of prey 1. Crypsis: –Increases recognition time –Only have to make prey less profitable than other prey item

55 2. rarity Most predators eat more than one type of prey Most target more common species, or PT (= apostatic selection) Example: prey choice of bird

56 Optimal foraging theory Maximize benefit/cost ratio of energy Natural selection should result in traits that allow species to shift behavior / growth patterns to maximize efficiency of resource acquisition under changing environmental conditions

57 Optimal “Foraging” by Plants Environment Low light Limited water or nutrients Optimal Growth Pattern Produce more leaves (less roots) Produce more roots (less leaves)

58 Optimal foraging Herbivores, carnivores –Optimize foraging by: Minimize energy/water use in search, chase, subdue, eating prey Select prey based on availability and value

59 Size of pumas and their prey Figure 7.19

60 Fig 7.25

61 Optimal foraging theory predicts maximum energy intake But, many studies do not find animals behave optimally Why?


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