Class Notes (839,242)
United States (325,886)
BSC 108 (56)
Lecture 18

BSC 108 Lecture 18: Biology Chapter 18 Notes

8 Pages

Biological Sciences
Course Code
BSC 108
Christina Yates

This preview shows pages 1,2 and half of page 3. Sign up to view the full 8 pages of the document.
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. •
More Less
Unlock Document

Only pages 1,2 and half of page 3 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.