Transcript Ecology
Chapter 52 Section 1 & 2 What Does Ecology Do? Ecology Reveals the richness of the biosphere What is Ecology? Study of interactions between organisms and the environment Ecology Has a long history as a descriptive science & is a rigorous experimental science Organisms and the Environment The environment of any organism includes: Abiotic Nonliving components Biotic Living components Biota All the organisms living in the environment What role does the Environment play for organisms? Affects the distribution and abundance of organisms Kangaroos/km2 > 20 10–20 5–10 1–5 0.1–1 < 0.1 Limits of distribution Southern Australia has cool, moist winters and warm, dry summers. Climate in northern Australia is hot and wet, with seasonal drought. Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year. Southeastern Australia has a wet, cool climate. Tasmania Ways Ecologists Study the Environment Use: Observations Experiments Subfields of Ecology Organismal Ecology Studies how an organism’s structure, physiology, and behavior meet the challenges posed by the environment (a) Organismal ecology. How do humpback whales select their calving areas? Subfields of Ecology Cont’d Population Ecology Concentrates mainly on factors that affect how many individuals of a particular species live in an area (b) Population ecology. What environmental factors affect the reproductive rate of deer mice? Subfields of Ecology Cont’d Community Ecology Deals with the whole array of interacting species in a community (c) Community ecology. What factors influence the diversity of species that make up a particular forest? Subfields of Ecology Cont’d Ecosystem Ecology Emphasizes energy flow and chemical cycling between biotic and abiotic components (d) Ecosystem ecology. What factors control photosynthetic productivity in a temperate grassland ecosystem? Subfields of Ecology Cont’d Landscape Ecology Deals with arrays of ecosystems and how they are arranged in a geographic region (e) Landscape ecology. To what extent do the trees lining the drainage channels in this landscape serve as corridors of dispersal for forest animals? Biosphere • Is the global ecosystem, • Sum of all the planet’s ecosystems Ecology and Environmental Issues Ecology provides the scientific understanding underlying environmental issues Rachel Carson Started the modern environmental movement Ecologists follow the Precautionary Principle Humans need to be concerned with how their actions affect the environment Section 52.2 Concept 50.2: Interactions between organisms and the environment limit the distribution of species Dispersion Patterns Many naturalists have noticed a pattern of the ways plants and animals are distributed Palearctic Nearctic Tropic of Cancer (23.5N) Oriental Ethiopian Equator Neotropical (23.5S) Tropic of Capricorn Australian Dispersal and Distribution Dispersal • Movement of individuals away from centers of high population density or from their area of origin • Leads to distribution of species Species Transplants Species Transplants Organisms that are intentionally or accidentally relocated from original distribution How does this effect an ecosystem? Can disrupt the communities or ecosystems causing a change in food chain Behavior and Habitat Selection A Few Thoughts Some Organisms • Do not occupy all of their potential range Species distribution • May be limited by habitat selection behavior Biotic Factors These affect the distribution of organisms Interactions with other species Predation Competition Abiotic Factors These affect the distribution of organisms Temperature Water Sunlight Wind Rocks and soil Salinity Temperature Environmental Temperature How does this effect distribution of species? It can change biological processes Water How is water a factor that could influence species distribution? Sunlight How is sunlight a factor that could influence species distribution? Can influence photosynthesis Development and behavior of organisms sensitive to the photoperiods can be altered Wind How does wind effect different species? Amplifies the effects of temperature on organisms Rocks and Soil How are rocks and soil a factor that could influence species distribution? Limit the distribution of plants and thus the animals that feed upon them by: Physical Structure pH Mineral composition Climate Climate • Is the prevailing weather conditions in a particular area Four major abiotic components make up climate: Temperature Water Sunlight Wind Climate patterns can be described on two scales Macroclimate These are on the global, regional, and local level Microclimate In certain locations Mountain Tops, under a fallen log etc… Global Climate Patterns Global Climate Patterns Determined by the input of solar energy Location of Earth in space How Global Climate Is Determined (Input of Solar Energy) Sunlight Intensity • Plays a major part in determining the Earth’s climate patterns LALITUDINAL VARIATION IN SUNLIGHT INTENSITY North Pole 60N Low angle of incoming sunlight 30N Tropic of Cancer Sunlight directly overhead 0 (equator) Tropic of Capricorn 30S Low angle of incoming sunlight 60S South pole Figure 50.10 Atmosphere How Global Climate Is Determined Cont’d (Location In Space) SEASONAL VARIATION IN SUNLIGHT INTENSITY 60N June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere. 30N 0 (equator) March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. 30S Constant tilt of 23.5 September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere. How Global Climate Is Determined Cont’d GLOBAL WIND PATTERNS Arctic Circle 60N Westerlies 30N Northeast trades Doldrums 0 (equator) Southeast trades 30S Westerlies 60S Antarctic Circle Figure 50.10 Regional, Local, and Seasonal Effects on Climate Various features of the landscape contribute to local variations in climate What might be some of these? Bodies of Water Oceans and their currents, and large lakes 2 Air cools at high elevation. 3 Cooler air sinks over water. 4 Cool air over water moves inland, replacing rising warm air over land. 1 Warm air over land rises. Mountains Mountains have a significant effect on The amount of sunlight reaching an area Local temperature Rainfall Mountain Effect Cont’d 1 2 As moist air moves in off the Pacific Ocean and encounters the westernmost mountains, it flows upward, cools at higher altitudes, and drops a large amount of water. The world’s tallest trees, the coastal redwoods, thrive here. Farther inland, precipitation increases again as the air moves up and over higher mountains. Some of the world’s deepest snow packs occur here. 3 On the eastern side of the Sierra Nevada, there is little precipitation. As a result of this rain shadow, much of central Nevada is desert. Wind direction East Pacific Ocean Sierra Nevada Coast Range Seasonality The angle of the sun • Leads to many seasonal changes in local environments June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere. SEASONAL VARIATION IN SUNLIGHT INTENSITY March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth 60N experience 12 hours of daylight and 12 hours of 30N darkness. 0 (equator) 30S Constant tilt of 23.5 September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere.