Ecology

1. Ecology The study of Interactions

2. Ecology • Interactions between organisms and their biotic and abiotic environments. • Biotic = other organisms & their products. • Intraspecific (among same species) • Interspecific (among different species) • Abiotic = non-living environment • Climate, Mineral Soil, Atmosphere, Temperature, Humidity, etc. • BIG questions – involving lots of factors. • Difficult Research!

3. Ecology Broken down into sub-disciplines: • Organismal Ecology – how individual organisms work within their environments. • Physiological Ecology • Energy allocation, reproduction • Evolutionary Ecology • Adaptations to environments • Behavioral Ecology • How organisms act to accomplish certain goals.

4. Ecology • Population Ecology • Study of groups of organisms of the same species, usually living in a particular area = populations! • Often involves #’s • Population increase/decrease • Fecundity (reproductive capacity) • Factors influencing population size • Food, shelter, predation, etc.

5. Ecology • Community Ecology • Study of all organisms of all species occupying a particular area. • Usually, assemblages of species are typically studied (easier to deal with). • Predation • Competition • Disturbance • Succession • Community Structure • Energetics

6. Ecology • Ecosystems (“Systems Ecology”) • Community of organisms plus all abiotic factors. • Emphasis on energy flow & nutrient flow • Energy – unidirectional • Nutrients – cyclic • Lake • Pond • Patch of forest of a specific type.

7. Ecology • Landscape Ecology • Interactivity between different ecosystems. • “Edge Effects” • Biogeography • Distributions of organisms. • Clumped, Random, Uniform, etc. • Dispersal, range.

8. Ecology • Biosphere (“Global Ecology) • Largest area – how landscapes interact. • Global nutrient cycling • Ozone, Greenhouse gasses, etc.

9. Ecological Systems are Complex! Organism Population Community Ecosystem Landscape Biosphere

10. Organismal Ecology • Genetic influences • Response to stimulus, Taxis, Tropism, Migration. • Signals & Communication. • Mating & Parental Behaviors. • Social interactions. • Environmental influences. • Learning, Association, Cognition.

11. Interactions among Populations • Intraspecific (same species) • Population Size • Births/Immigration – Deaths/Emmigration • Growth • Births/Immigration > Death/Emmigration • Growth Rate (“Rate of Increase”) • Changes in Growth over time • Density = numbers/area

12. Interactions among Populations • Exponential Growth ∆N ∆t But… • Carrying Capacity • Available resources limit population size

13. Interactions among Populations • Dispersion = spacial distribution • Clumped • Uniform • Random

14. Interactions among Populations • Life History Differences • How specific organisms live their lives • Survivorship Curves • Type I – large mammals, ↑ parental care. • Type III – plants, fish, ↓ parental care. • Type II – many in between.

15. Interactions within Communities • Competition • Predation • Herbivory • Parasitism • Disease • Mutualism • Commensalism

16. Competition -/- • Exploitive – indirect usually, typically negatively-effecting species. • Light, water, “limiting resources” – limit population size. • Adaptations allow better (or poorer) resource exploitation (speed, root efficiency, etc.) • Competitive Exclusion • Resource Partitioning – to avoid competition. • Ecological Niche • Total of an organism’s use of biotic & abiotic resources – where it “fits” in the environment…sort of.

17. Predation +/- • Feeding! -- One species benefits at the expense of another species. • Leads to many adaptations: • Cryptic coloration (Camouflage) • For both predator & prey! • Aposematic coloration (Warning) • Mimicry (of unpalatable species) • (Herbivory) – a type of predation in which the prey is not killed, but is still at a disadvantage! • Aposematic & Mimicry in plants! • Chemical, Mechanical, & Symbiotic defenses.

18. Parasitism +/- • One species compromises another living host while living on or in it. • Feeding, protection, reproduction • Complex lifecycles • Endoparasites, Ectoparasites • Disease – sometimes. • “Pathogens” = disease-causing agents Misteltoe

19. Mutualism +/+ • “Symbiosis” between two organisms. • Both Benefit! • Clownfish/Anemone, Ant/Acacia, Legume/Rhizobium.

20. Commensalism +/o • One species benefits, the other is neutral. • Algae on shells & fish, Cattle Egrets, Insects following leafcutters/army ants.

21. Changes in Communities over TIME • Succession: progressive changes in community structure over time. • Primary Succession – from bare rock. • Secondary Succession – from some intermediate state. • Disturbance – not always bad • “Intermediate Disturbance Hypothesis”

22. Trophic Structure of Communities • Food Pyramids • Food Webs • Producers • 1o consumers • (herbivores) • 2o consumers • Decomposers

23. Diversity • Species Richness • Species Evenness • “Functional Diversity” • emphasis on species contributions, rather than on the species themselves. • Ties in with Ecosystem Functioning • Rivet Hypothesis • Redundancy Hypothesis

24. Control of Community Structure • “Top-Down” Control • Top predators “control” community structure. • “Bottom-Up” Control • Producers/Herbivores “control” community structure • Foundation Species – establish & facilitate colonization by others. • Keystone Species – Large roles in community, controlling other species’ fates. • Invasive Species – “new” species with few predators & fast growth.

25. Biogeography: Large-Scale Distributions • Dispersal & Dispersal Mechanisms • Long-range vs. Short-range • Range expansion or compression • Potential vs Actual Range • Accidentals • Non-native species • Equator-Pole gradients • Altitude gradients

26. Alititudinal Gradients • Rain Shadow

27. Biosphere • Global Climate Change…

28. Biosphere • Global Climate Change…