Ecology. (Freeman Chs 50, 52-53) 11 March Video: browser. ECOL 182R UofA K. E. Bonine

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1 Ecology (Freeman Chs 50, 52-53) 11 March 2010 ECOL 182R UofA K. E. Bonine Video: browser 1

2 Lecture Schedule (middle third) 18 Feb KB Fungi, Ch31 23 Feb KB Prokaryotes & Protists, Ch28&29 25 Feb KB Plant Diversity, Form, Function, Ch30&40 2 Mar KB Plant Form and Function, Ch36&37 4 Mar KB Plant Function, Ch38&39 9 Mar KB Plant Ecology, Ch50,52,53 11 Mar KB Ecology, Ch50,52, Mar Spring Break 23 Mar KB Biology of the Galapagos Wikelski 2000 and 25 Mar KB - Part 2. Discussion and Review. 30 Mar KB - EXAM 2 2

3 Ecology 3

4 What would an ecologist say about this picture? 4

5 What is Ecology? Study of thedistribution and abundance of organisms. Study of the myriad interactions among organisms and their environment. Includes both biotic and abiotic interactions/components. 5

6 Distribution and Abundance Primary Driver is Temperature Precipitation weather is short-scale climate Secondary Drivers: Resources Competition Predation (interspecific interactions) 6

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8 One tree in xxxx with same ant diversity as Britain Pimm and Jenkins

9 Species Richness and x Primack

10 [Phylogeny and Biogeography] Also important drivers of distribution and abundance xxxxxxxxxxx ROLES 10

11 What else explains some of the observed patterns of species distribution and abundance? Populations Life-history strategies Intraspecific interactions Communities Interspecific interactions 11

12 Population: individuals of the xxxx species xxxxxxxxxx in the same xxxxxx& actually x Population sizes change over time! 12

13 Community: all species living in the xxxx place at the same Also Dynamic 13

14 Dynamics differ enormously across populations and species. Cactus finch Arctic skua 14

15 Age Structure Diagram Humans in Australia 15

16 Life History Variation 16

17 Life History Variation 17

18 Unlimited Growth Bacteria: Binary fission (1 cell 2 cells) Pop. can every 1/2 hour > 1 million after 10 hours! Time # , ,048,576 18

19 Unlimited Growth Exponential growth; the exponential curve. 19

20 Unlimited Growth Exponential growth: constant doubling time xxxxxxxxxx growth rate. 20

21 Multiplied =Exponential Exponential Vs. Added Arithmetic 21

22 Exponential growth the Exponential Equation dn/dt = N (b - d) Maximum (b - d) for a pop. is its intrinsic rate of increase, r. dn/dt = r N (if you prefer, N/ t) 22

23 Biotic Potential... Exponential! 23

24 Why isn t the universe full of flies? 24

25 Resources NOT unlimited J vs. S Exponential vs. Logistic 25

26 K = carrying capacity 26

27 Exponential Vs. Logistic GROWTH xxx equation Pop. growth rate = exponential growth rate x a factor that slows growth as pop. approaches carrying capacity. dn/dt = (b-d)n x (K-N)/K xxxxx = r, K = carrying xxxxxx 27

28 To determine K we d need to know: (K = carrying capacity) What resources are required, in what amount Rates of resource renewal How much habitat is required Etc 28

29 r vs. K selected 29

30 Human Population Miller

31 Exponential Growth MALTHUS VanDyke 2003 Human Population Growth Ricklefs 2001 Logistic Growth Ricklefs 2001 Ricklefs

32 Exponential Growth N = N 0 e kt N = future population size at next time interval N 0 = population size at beginning of time interval e = (base of natural logarithms) k = rate at which population increases over time interval t = number of time intervals (usually years) If k = (1.36% annual increase), and N 0 = 6.2 billion what will population be in 20 years? N = (6.2x10 9 ) x e (0.0136x20) N = 8.14x109 (8.14 billion) 32

33 Exponential Growth Doubling Time N = N 0 e kt T d = 2N 0 = N 0 e k T d ln 2 = kt d R = growth rate therefore k=r/100 (e.g., R = 1.36%) T d = ln2/k T d = 0.693/k T d = 0.693/(R/100) T d = 69.3/R ~ 70/R RULE OF If R = 10% then T d = 70/10 = 7 years If R = 1.36% then T d = 70/1.36 = 51.5 years 33

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35 Metapopulation... Spatially disjunct groups of individuals with some demographic or genetic connection largely independent yet interconnected by migration 1. All local populations must be prone to extinction 2. Persistence of entire population requires recolonization of individual sites. (p.193 in VanDyke text)...a population of populations 35

36 Source b vs. d Sink 36

37 Metapopulation Examples: Hydrothermal Vents Lowland Leopard Frogs (thanks to Don Swann) 37

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40 Metapopulation Dynamics 40

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45 Chytrid Fungus 45

46 Habitat- Human Pinworm (Nematode) Giraffe MRSA Thermus aquaticus Methicillin-resistant Staphylococcus aureus Taq polymerase 46 Canyon treefrog

47 The Niche Resources limit population growth Each species requires many specific resources: Food Water Shelter Range of OK abiotic conditions and plays specific roles in the ecosystem 47

48 The Niche Resources limit population growth Niche: total range of abiotic & biotic conditions tolerated, resources used, and roles played. 48

49 The Niche Resources limit population growth Niche: total range of abiotic & biotic conditions tolerated, resources used, and roles played. 49

50 Fundamental niche: niche that xxxxxxxx can be occupied. Amt. of Shade Axes shown are for saguaro. In reality, there are >>3 axes!! Soil Moisture Tem per ature Realized niche: part of the fundamental niche that s xxxxxx occupied, in the presence of other species. Amt. of Shade Soil Moisture Realized Niche Tem per ature 50

51 Habitat vs. Niche Which one is best described as an organism s xxxxxx? Why? Which one is best described as an organism s xxx? Why? 51

52 What could keep a species out of part of its fundamental niche? Predators Amt. of Shade Soil Moisture Tem per ature in some OK sites. Competitors Realized Niche monopolizing some necessary resources. Amt. of Shade Soil Moisture Tem per ature 52

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54 PREDATION 54

55 Bio control example: Prickly pear, Australia Introduced potted plant No native enemies YEAR SQ KM INFESTED 0 40,000 90,600 93,700 55

56 Herbivore (Cactoblastis moth) introduced Plant nearly gone by Biological Control 56

57 Predator/Prey Dynamics What s so interesting about predation? Predator & prey pop. growth aren t independent. 57

58 Data from Canadian trapping records. Why do they cycle? 58

59 Interactions between pairs of species are amazingly diverse. 59

60 Interspecific Interactions Interactions between 2 species can benefit (+) harm(-) have no effect (0) on each of them. 60

61 Interspecific Interactions Competition: Both do worse when together. 61

62 Competition In nature, resources are limited in availability. Competition: resource use by 1 individual that reduces its availability for others. 62

63 Competition WHO competes? A. Intraspecific comp: individuals of the same species. Comp. for mates Comp. for space 63

64 Competition WHO competes? B. Interspecific comp: individuals of different species. Comp. for space & water 64

65 Competition HOW does comp occur? 1. Interference comp: individuals have direct confrontations. 65

66 Competition HOW does comp occur? 1. Interference comp: individuals have direct confrontations. Dragonflies: 1st sperm in fertilizes female. 2nd male to mate w/ female scoops out 1st male s sperm! 66

67 Competition HOW does comp occur? 2. Exploitation comp: Indirect depletion of shared resources. 67

68 Interspecific interference Interspecific exploitation Intraspecific interference Intraspecific exploitation 68

69 69

70 Example: How do 2 barnacle sp. coexist in the rocky intertidal zone? Both do best in low wet zone. 70

71 Example: How do 2 barnacle sp. coexist in the rocky intertidal zone? Both do best in low wet zone. Hypothesis: the worse competitor gets pushed to high dry zone, but is able to hang on. arthropods 71

72 Example: How do 2 barnacle sp. coexist in the rocky intertidal zone? Both do best in low wet zone. Hypothesis: the worse competitor gets pushed to high dry zone, but is able to hang on. Test: if better competitor is removed, does the poorer move into that area? 72

73 Yes. Removing the lower sp. causes the upper sp. to shift to the wet habitat (but not vice versa). 73

74 Attempted Predation & Interspecific Competition 74

75 The Interaction Grid Effect on Species 2 Effect on Species Mutualism Antagonism - Antagonism Competition 0 Commensalism Amensalism 75

76 Interspecific Interactions Commensalism: One does better when together; one is unaffected. 76

77 Interspecific Interactions Amensalism: One does worse when together; one is unaffected. 77

78 Interspecific Interactions Antagonism: There are many kinds of antagonistic interactions. One does worse, one does better when together. 78

79 Forms of antagonism (-+): 1.Predation Killing + eating of prey by predator. 79

80 Forms of antagonism (-+): 1. Predation 2.Herbivory Partial consumption of plants by animals. 80

81 Forms of antagonism (-+): 1. Predation 2. Herbivory 3.Parasitism Partial consumption of animals by animals. Endoparasite: lives inside host Ectoparasite: feeds from the outside 81

82 Forms of antagonism (-+): 1. Predation 2. Herbivory 3. Parasitism 4.Pathogens Microorganisms living & reproducing inside hosts & causing disease. 82

83 Interspecific Interactions Mutualism: Both do better when together. 83

84 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Pollination mutualism Animal: gets food. Plant: gets pollen moved between flowers. 84

85 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Seed dispersal mutualism Animal: gets food. Plant: gets seeds moved to good spot to germinate. 85

86 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Protection mutualism Ant: gets food. Aphid: gains protection from antagonists. 86

87 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Protection mutualism Ant: gets food. Cactus: gains protection from herbivores. 87

88 Mutualism: Many Kinds of Mutualism Each species uses its mutualist to get things it requires to survive & reproduce. Protection mutualism Cleaner: gets food. Host: gets its ectoparasites removed. 88

89 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Nutrition mutualism Plant: gets nutrients. Bacteria: gains habitat. 89

90 Many Kinds of Mutualism Mutualism: Each species uses its mutualist to get things it requires to survive & reproduce. Here, Rhizobium bacteria make N available to plant in usable form. 90

91 Many Kinds of Mutualism This is a xxxxxx mutualism: partners are physiologically integrated Here, Rhizobium bacteria make N available to plant in usable form. 91

92 Many Kinds of Mutualism Other mutualistic symbioses coral lichens 92

93 Most between-species interactions have parallels to within-species interactions. (+-) Altruism (++) Intraspecific competition (--) 93

94 Lots of species seem similar 94

95 Coexistence There must be mechanisms that permit similar species to coexist. 1. Resource partitioning Splitting up of shared, limiting resources. Example: varying root depths 95

96 Example: 5 warbler sp. xxxxx on same insect food by feeding in different parts of the same tree. 96

97 Example: 5 warbler sp. coexist on same insect food by feeding in different parts of the same tree. Fund. niche of each sp. = entire tree. Realized niche of each sp = part of tree it actually feeds in. 97

98 Predator/Prey Dynamics Influences Coexistence What s so interesting about predation? Hypothesis: Predators reduce prey #. So, more prey species can coexist on a limiting resource. Test: remove predators. 98

99 Starfish EAT EAT Mussels Limpets COMPETE mollusk gastropod Space is the limiting resource. 99

100 Starfish EAT EAT Mussels Limpets COMPETE Space is the limiting resource. What happens if starfish removed? 100

101 Mussels Limpets What happens if starfish removed? Mussels outcompete, eventually exclude limpets. 101

102 Starfish EAT EAT Mussels Limpets COMPETE Starfish = keystone predators. Their presence increases species diversity. 102

103 Keystone predator. Keystone. xxxxxxx species plays larger xxxx in ecosystem than you would xxxxxx from numbers or biomass alone. 103