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BSC 108 (56)
Lecture 18

BSC 108 Lecture 18: Biology Chapter 18 Notes

8 Pages
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Department
Biological Sciences
Course Code
BSC 108
Professor
Christina Yates

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Biology Chapter 18 Notes Humans • By far the most abundant large animal • Requires vast amounts of materials and space • Has devastated the environment for many other species • Have a disproportionately high impact on the environment An Overview of Ecology • Ecology ➢ Is the scientific study of the interactions between organisms and their environments • The environment ➢ Can be divided into two major components. ➢ The abiotic component: The nonliving chemical and physical factors in an environment. ➢ The biotic component: The living factors in an environment. Natural History • Natural history as a “discovery science” remains fundamental to ecology A Hierarchy of Interactions • Ecology can be divided into four increasingly comprehensive levels: ➢ Organismal ecology: Is concerned with evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments ➢ Population ecology: Is concerned with populations, groups of individuals of the same species living in the same area. Concentrates mainly on factors that affect population density and growth. ➢ Community ecology: Is concerned with communities, assemblages of populations of different species. Focuses on how interactions between species affect community structure and organization. ➢ Ecosystem ecology: Is concerned with ecosystems, which include all the abiotic factors in addition to the community of species in a certain area. Focuses on energy flow and the cycling of chemicals among the various abiotic and biotic factors. Biosphere • The biosphere ➢ Is the global ecosystem Global Distribution Patterns • Global distribution patterns ➢ Reflect regional differences in climate and other abiotic factors. • Patchiness of the environment on a local scale reveals a mixture of characteristics. Habitats • Habitats ➢ Are specific environments in which organisms live. ➢ Reveal patchiness on an even smaller scale. Abiotic Factors of the Biosphere • On a global scale, ecologists have recognized striking regional patterns in the distribution of terrestrial and aquatic life. Energy Source • Solar energy powers almost all ecosystems. • Availability of sunlight affects aquatic and terrestrial environments. • There is life deep in ocean. Powered by chemoautotrophic bacteria that get energy from inorganic chemicals. Temperature • Environmental temperature ➢ Is an important abiotic factor because of its effect on metabolism. • Some extraordinary adaptations enable some species to live in extreme temperatures. Water • Aquatic organisms may face problems with water balance. • For terrestrial organisms, the main water problem is drying out. Wind • Some organisms depend on nutrients blown to them by wind. • Organisms such as plants depend on wind to disperse pollen and seeds. • Wind ➢ Can also affect the pattern of a plant’s growth Rocks and Soil • Soil variation contributes to the patchiness we see in terrestrial landscapes. • In streams and rivers, the composition of the soil can affect water chemistry. Adaptations • Three types of adaptations enable organisms to adjust to changes in their environments: ➢ Physiological ➢ Anatomical ➢ Behavioral Physiological Responses • In mechanisms of temperature regulation, responses by organisms occur quickly. • Acclimation ➢ Is a physiological response that is longer term. • The ability to acclimate ➢ Is related to the range of environmental conditions a species naturally experiences. • Among vertebrates ➢ Birds and mammals can tolerate the greatest temperature extremes because they are endotherms. ➢ Reptiles are more limited in the climates they can tolerate because they are ectotherms. Anatomical Responses • Many organisms respond to environmental challenge with some type of change in body shape or anatomy. Behavioral Responses • In contrast to plants, most animals can respond to an unfavorable change in the environment by moving to a new location. • Humans exhibit an especially rich range of behavioral responses. What Is Population Ecology? • Population ecology ➢ Is the study of how members of a population interact with their environment ➢ Focuses on factors that influence a population’s size, growth rate, density, and structure. Biomes • Biomes ➢ A major terrestrial or aquatic life zone, characterized by vegetation type in terrestrial biomes or the physical environment in aquatic biomes. Aquatic Biomes • Occupy ~75% of Earth’s surface. • Determined by their salinity and other physical factors. • Freshwater biomes –Lakes, streams, rivers and wetlands ➢ Usually a salt concentration less than 1%. • Marine biomes –Oceans, intertidal zones, coral reefs, and estuaries ➢ Usually a salt concentration ~3%. Freshwater Biomes • A disproportionate share of biodiversity, ~6% of all species. • Use for drinking water, crop irrigation, sanitation and industry. • Two categories ➢ Standing water-includes lakes and pond. ➢ Flowing water-includes rivers and streams Lakes and Ponds • In lakes and large ponds, ➢ The communities of plants, algae, and animals are distributed according to the depth of water and its distance from shore. Rivers and Streams • Rivers and streams ➢ Are bodies of water flowing in one direction. ➢ Support quite different communities of organisms than lakes and ponds • Human activities have affected many streams and rivers. Wetlands • Transitional biome between an aquatic ecosystem and a terrestrial one. ➢ Among the richest of biomes in species diversity. Estuaries • Estuaries ➢ Are areas where a freshwater stream or river merges with the ocean ➢ Are one of the most biologically productive environments on Earth How Climate Affects Terrestrial Biome Distribution • Terrestrial biomes are determined primarily by climate, especially temperature and rainfall. • Heated by the direct rays of the sun, air at the equator rises, then cools, forms clouds, and drops rain • Altitude effects vegetation and animal distribution • Proximity to large bodies of water and the presence of landforms such as mountain ranges also affect climate. Terrestrial Biomes • The distribution of terrestrial biomes depends largely on climate. • If the climate in two geographically separate areas is similar, the same type of biome may occur in them. • Are named for major physical or climatic features and for their predominant vegetation The Water Cycle • All parts of the biosphere are linked by the global water cycle and by nutrient cycles. Human Impact on Biomes • Humans have been using more and more resources from the environment. Can not sustain this. •
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