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1 Mon. Tues. Wed. Thurs. Fri. Week of Nov. 10 Week of Nov. 17 River ecology lab – dress for weather Lab Exam (bring calc.) Week of Nov. 24 No lab – Thanksgiving No lecture Week of Dec. 1 Independent project presentations Exam 3
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2 Ecology does not roll over into Genetics Last chance to take Genetics.
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3 Sp. interactions – 17 18 (through fig. 18.7), 19 20 (only covering p. 391) Community ecology – 21 22
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4 Structure of course Environmental variability Organisms Ecosystems Populations Species interactions Communities Applied Ecological Issues
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5 + + Mutualistic interactions AB
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6 Different types of mutualisms 1.Those involving energy, nutrients, and/or water (Trophic mutualisms)Examples? 2.Those involving defense (Defensive mutualisms) Examples? 3. Those involving dispersal (Dispersive mutualisms) Examples?
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7 Lichens
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8 Obligate mutualism – species are so dependent on each other that they cannot live without each other
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9 Acacia trees and acacia ants
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10 Trees without ants Trees with ants % of shoots with herbivores on them
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11 May 25 June 16 Aug. 03 Acacia height (cm) 0 120 60
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12 Which are more general? seed dispersal or pollination mutualisms
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13 Figure 20.16
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14 Structure of course Environmental variability Organisms Ecosystems Populations Species interactions Communities Applied Ecological Issues
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15 Communities What is a community? How are communities described? How are species organized within a community? How do communities change over time?
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16 Community: an association of populations of different species living in a particular area Community ecology: focus is understanding the diversity and relative abundance of species in the community
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17 Questions asked by community ecologists What determines the number of species in a community? How does disturbance affect community structure? Does adding new species change the way a community functions?
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19 Figure 21.6a Ecotone- zone of transition between 2 distinct communities
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20 Figure 21.9 boundaries less distinct
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21 Communities What is a community? How are communities described? How are species organized within a community? How do communities change over time and space?
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22 How are communities described? number of species = species richness evenness = # individuals/species diversity = richness and evenness relative abundance
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23 Figure 21.18 Relative abundance few dominant many rare
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24 5 species high evenness 5 species lower evenness
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25 Diversity = combination of richness and evenness - contribution of species weighted by relative abundance
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26 5 species high evenness 5 species lower evenness Which has higher diversity?
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27 What determines diversity of a community?
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28 What determines diversity of a community? 1.diversity is related to area 2.diversity is related to variability Lots of other theories that attempt to explain controls on diversity
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29 Figure 21.20 one of the most common patterns in ecology
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30 What determines diversity of a community? 1.diversity is related to area 2.diversity is related to variability Lots of other theories that attempt to explain controls on diversity
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31 Figure 23.5
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32 Hard to separate variability and area - typically larger areas have more habitat variability Lesser Antilles – island size and habitat diversity vary independently - two kinds of islands - tall volcanic – diverse habitats - low raised seabed – 1 habitat - both kinds of islands come in all sizes
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33 Figure 21.21
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34 Communities What is a community? How are communities decribed? How are species organized within a community? How do communities change over time?
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35 How are species organized within a community?
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36 Suppose there are 3 species in a community, species A, B, and C. When you remove species A from the community, species C goes extinct. What can you conclude about the relationship between species? a.Species A is a predator of species B. b.Species A is a prey of species C. c.Species B is a competitor of species C. d.All of these are possible.
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37 Figure 21.12
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38 Connectedness web Starfish Snail ChitonsLimpetsMusselsBarnacles
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39 Energy web Starfish Snail ChitonsLimpetsMusselsBarnacles
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40 Functional/interaction web Starfish Snail ChitonsLimpetsMusselsBarnacles
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