1What is Ecology?• The study of the interactions between organisms and their environment.– Organism – plant, animal, microbe…– Environment –• Abiotic– Non-living components – soil, water, nutrients…• Biotic– Interactions with other organisms – competition, predation, symbiosis…– Examples -What is Ecology?PhysiologyGeneticsSystematicsTaxonomyMicrobiologyEcologyandEvolutionDevelopmentalBiologyOrganizational levels in Ecology• Organismal –• Population –• Community –• Ecosystem –Questions at different Organizational levels in Ecology• Organismal – How individuals are affected by their biotic and abiotic environments.• Population – Trends and fluctuations in abundance or density related to biotic or abioticenvironment. • Community – How do interactions among species determine distribution and abundance of populations in a particular area or habitat. • Ecosystem – How do patterns of energy, mass and nutrients flow through ecosystems.2Ecology as a science• Ecology is a science…so what is a science?• Science – systematic methodology to develop predictive models about the natural world.– Seeks to explain natural phenomena– Pose, develop and test hypotheses– Does not prove anything, refines models that make predictions about the natural worldProperties of hypotheses• Must be falsifiable• Must be testable• Must make a prediction about some natural phenomenon• Is neither proven or disproven. • Observations (results of experiments) either support or do not support a hypothesisTheory vs. “Theory”• Common language use of theory – conjecture, opinion or speculation– E.g. a political pundit has a theory about who will win the presidential election in November 2008 • Scientific use of theory – well tested and supported model describing a natural phenomenon– E.g. a scientist, using the theory of gravity, can plot the position and speed of the earth in November 2008– A theory is formed from hypotheses that are repeatedly tested and supported.– A theory is the highest level of scientific understanding3An Ecological Theory• Populations will compete for limited resources.• Turn this into a hypothesis…Environmentalism• Environmentalism is not a science– A political movement or world view– Does not make predictions, test hypotheses– Seeks to protect and conserve natural environments– Belief that humans have a moral obligation to do no harm• Not to be confused with the science of conservation biology (a subdiscipline within ecology)– The ecological study of rare and endangered species. History of the Environmental Movement• Early 1900’s – extinction of passenger pigeon, near extinction of buffalo motivated Woodrow Wilson to form the US National Park System– First national parks- Yellowstone and Yosemite• 1949 – Aldo Leopold – A Sand County Almanac– Humans have a moral responsibility to not harm the environment• 1960 - Rachel Carson – Silent Spring ,book that sparked US environmental movement.– Dangers of pesticide use (DDT)• Modern environmental groups –Greenpeace, Sierra Club• 1973 – Endangered Species ActEcology and Environmentalism – blurred lines• Thomas Malthus (1798) – 1stto have concerns about human population sizes and sustainability– 1stpopulation biologist by extension4Summary• Ecology is a science• Conservation biology is a science• Environmental biology is not a science• Ecologists or conservation biologists are scientists and may also be environmentalists• Environmentalists are not scientists, but may also be ecologists or conservation biologistsThe most important theory in biology…• Theory of evolution• Simply states that the genetic composition of populations changes over time.• An example -Natural Selection • One mechanism for evolution• Requires the following be true– Populations are variable– Variations are heritable– Variations affect individuals ability to acquire resources– Resources are limited, individuals compete, and those who are best at getting resources reproduce the most -> are most fit• These are all hypotheses, we should be able to design experiments to test their predictions.Environmental Protection Agency• Started in December 1970• Major initiatives– Energy star program– Car fuel economy ratings– Ban of DDT– Clean Air Act– Water quality monitoring– Regulation of hazardous waste disposal– Recent change – carbon dioxide5Fitness in the Environment• In natural selection, all that matters is how many offspring you produce.• Fitness is not defined by survival• Fitness is defined by number of offspring produced– Example• Two birds, Bob and Tom, live in a very harsh environment– Bob – survives for 5 years, reproduces in three years and produces 6 young– Tom – only survives two years, reproduces once, but produces 8 young in one yearModern Example…• Drought on island reduced seed abundance• Bird abundance drops with seed abundance• Birds with larger beaks can utilize a wider variety of seeds• Beak size is heritable• Mean beak size changed during drought6Adaptive Radiation• Rapid evolution of a group stemming from a single common ancestorSpeciationHabitat AHabitat BAAAAAAAAaaaaaSpeciationHabitat AHabitat BAAAAAAAAaaaaaColonizationAAaSpeciationHabitat A – favors phenotype AHabitat B – favors phenotype aAAAAAAAAaaaaaaaaaa7SpeciationHabitat A – favors phenotype AHabitat B – favors phenotype aAAAAAAAAaaaaaaaaaaIsolation + different selection pressures -> divergenceMisconceptions about natural selection and evolution• Is not a random process• Does not lead to “better” species, it is non-directional• Can result in very rapid changes, as fast as the environment can changeNatural Selection and Ecology• Ecology is the study of the interactions between organisms and their environment (biotic and abiotic)• Natural selection describes a process through which populations compete for limited resources• Thus, the sciences of ecology and evolution are very tightly linked.PhysiologyGeneticsSystematicsTaxonomyMicrobiologyEcologyandEvolutionDevelopmentalBiologyHistory of Life on Earth• Earth formed ~5-6 bya• Not hospitable for life for 1-2 billion years• First fossilized life 3.8 bya (3,800,000,000)8Abiotic Synthesis• Early Earth atmosphere– No O2– H2O H2NH4CH4– High energy– Formed simple amino acids• Amino acids