A.EcoIntro - Ecology Introduction Why am I here? Ecos =...

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Unformatted text preview: Ecology Introduction Why am I here? Ecos = “home” Ecos Ecology: the study of • …where an organism lives. – Range – Habitat – Distribution • …how/why it lives there. – Environment: factors of the habitat that affect the organism – Niche: role of the organism affecting the environment Ecology THE REALM OF ECOLOGY •Biosphere Biosphere Ecosystems •Ecosystem •Community •Biosphere Biosphere Ecosystems •Ecosystem Communities •Population •Organism Populations Organisms Heyer THE REALM OF ECOLOGY •Community Communities •Population •Organismal Ecology: How an individual organism adjusts its physiology and/or behavior to respond to its environment. Populations Organisms 1 Ecology Introduction THE REALM OF ECOLOGY • Biosphere Biosphere Ecosystems • Ecosystem • Community • Population Ecology: Communities Interactions among members of the same species in a given habitat. Populations THE REALM OF ECOLOGY • Biosphere Ecosystems • Ecosystem • Community Ecology: Interactions among members of all of the species in a given habitat. Organisms THE REALM OF ECOLOGY • Biosphere • Ecosystem Ecology: Interactions between the species in a given habitat and their physical environment. Biosphere Communities Populations Organisms Biosphere Ecosystems Communities THE REALM OF ECOLOGY • Biosphere Ecology: Interactions among all the ecosystems on the planet — Earth as a living system. Biosphere Ecosystems Communities Populations Organisms WHAT IS SCIENCE ? • Attempts to discover the order in nature • Makes predictions about what will happen • Methodical process of discovery and understanding Heyer Populations Organisms WHAT IS SCIENCE ? • Discrimination of what is true (reality) from what only appears to be true (illusion, prejudice, & story-telling) “Science as a way of knowing” 2 Ecology Introduction PROCESS SCIENTISTS USE TO ANSWER PROCESS SCIENTISTS USE TO ANSWER QUESTIONS ABOUT NATURE QUESTIONS ABOUT NATURE It all starts with Observations • Careful, meticulous, well-documented observations! • Naturalists and explorers • Scientific method – – – – – – Detailed descriptions, illustrations, maps, & anecdotes • Published scientific reports Observations Question Hypothesis Prediction Experiment Let the observations inspire specific questions! Why do frogs call at night? – Peer-reviewed journals • Personal experiences Proximate vs. Ultimate Questions ß Proximate questions (descriptive) ß what is it? ß how does it function? Propose plausible answers to your question. • • • • ß Ultimate questions (causal) ß why is something the way it is? ß what would be predicted about how it reduced predation rates reduced loss of foraging reduced water loss rates reduced phone rates ß breaths ß reproduces ß is related to other organisms Ecological Questions • Biogeography Species absent because – Provides a good starting point for understanding what limits the geographic distribution of species Yes Dispersal limits distribution? No Area inaccessible or insufficient time Yes Behavior limits distribution? No Habitat selection Yes Biotic factors (other species) limit distribution? No Predation, parasitism, competition, disease Water Chemical Oxygen factors Salinity pH Abiotic factors Soil nutrients, limit etc. distribution? Temperature Physical Light factors Soil structure Fire Moisture, etc. The Hypothesis • Hypotheses are possible explanations of an observation. • Scientists formulate hypotheses based on: 1) previous knowledge 2) inference from similar situations 3) common sense • The more basic facts you know, the better your questions. Figure 50.6 Heyer 3 Ecology Introduction RELATIONSHIP BETWEEN RELATIONSHIP BETWEEN The Hypothesis HYPOTHESIS AND PREDICTION HYPOTHESIS AND PREDICTION specific prediction Word it as falsifiable (null hypothesis) • If the hypothesis is correct.... • Then we predict the following outcome from our experiment • Formulate a • • Formulate falsifiable alternative hypotheses • Design tests of the prediction (experiments) Hypothesis Testing SCIENTIFIC METHOD • Hypothesis-driven science – Prediction • Reproducibility: Repeated testing of a • If …then hypothesis precedes its tentative acceptance. • Only testable hypotheses are worthwhile. • Untestable hypotheses are not generally considered science. Test the Hypothesis • • • • Observations Questions Hypothesis/Predictions Tests (Experiments) • Control Group • Experimental Group – Standardized Variables – Independent Variable • Data/Results – Dependent Variable • Conclusion Heyer – Test the prediction Evolution of Life History Traits in Jamaican Guppies Observations: • Guppies live in river pools. • Some pools have large cichlid fish predators. • Some pools have smaller killifish predators. • Some pools have neither predator. 4 Ecology Introduction Experiment •Question: Does the type of predator present alter the growth rate/maturation of guppies? More observations •Prediction: If guppies are exposed to a different predator, then they will alter their growth rate and maturation. Results Doing Science 1) Get all background information possible (lots of it normally) 2) Collect data (often several years of work) 3) Analyze data (can take months or years) 4) Write up results & submit for peer review and publication (often >1 year until publication) Ecology and Environmentalism • Silent Spring, 1962, by Rachel Carson ß Credited with starting the modern environmental movement ß Specifically, alerted the public to the side impact of DDT use upon bird populations ß Generally, publicized that human “control of nature” often came with severe retributions Ecology and Environmentalism • The precautionary principle ßBasically states that humans need to be concerned with how their actions affect the environment ßIt is a lot more plausible to prevent environmental degradation than to try to remediate it Figure 50.4 Heyer 5 Ecology Introduction Ecology and Environmentalism • Ecology — Provides the scientific understanding underlying environmental issues • Sustainable Development ß Long-term prosperity of both humans and ecosystems ß Commitment to protect and preserve biodiversity ß “Stewards of the land” • Decisions that benefit future generations Real and potential human insults to the integrity of the biosphere 1. Global contamination (pollution) 2. Global warming 3. Habitat destruction 4. Nuclear winter Nuclear 5. Destruction of the ozone layer 5. Figure 50.1 The Miraculous Coincidences of Planet Earth • Unique essential combination of factors compatible with life. • Water in all three phases • Size: smallerfilose oxygen bigger fitrap hydrogen • Distance from sun: 5% closer fitoo hot 1% farther fitoo cold Very likely unique in the universe! • Speed of rotation, tilt of axis, speed & shape of solar orbit fi prevent lethal extremes • Gas giants in outer solar system deflect interstellar debris Even our position in the galaxy is ideal! You are here If you were here, the high stellar density would create radiation and gravitational disruption. If you were out here, there would be insufficient heavy elements to form planets. Biophilia a love of life and its forms Our innate sense of connection to nature may eventually motivate a realignment of our environmental priorities Heyer Biologist Carlos Rivera Gonzales examining a tiny tree frog in Peru 6 ...
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