People & Earth's Ecosystem PDF

PEOPLE & EARTH’S ECOSYSTEM NATURE & SCOPE OF ECOLOGY LEVELS OF ORGANIZATION in ECOLOGY Ecology: Environment, Environmentalism, Environmental BIOSPHERE: broadest level of Science....

PEOPLE & EARTH’S ECOSYSTEM NATURE & SCOPE OF ECOLOGY LEVELS OF ORGANIZATION in ECOLOGY Ecology: Environment, Environmentalism, Environmental BIOSPHERE: broadest level of Science. organization. Focuses on understanding It contains all ecosystems, the thin biodiversity's impact on ecological volume of Earth, and its atmosphere function. interactions among living that supports life. the biosphere is as organisms and their surroundings thick as its peel. It studies ecological systems at ECOSYSTEM: These are communities various levels: individuals, of organisms and their non-living populations, ecosystems, biosphere environment CONNECTION TO EVOLUTIONARY COMMUNITY: It consists of BIOLOGY populations of various species that live in the same habitat and interact Hawks feeding on mice impact with each other. mouse population and may eventually lead to selection for mice POPULATION: It comprises a group of with fur as camouflage organisms of the same species that live in a specific geographical area 2 Main Themes in Ecology and reproduce. 1. Where do organisms live? Why? ORGANISM: This is the simplest level To understand why certain species of organization, an individual living thrive in specific habitats. thing. 2. How many organisms are present? COMMUNITIES & ECOSYSTEMS Why? HABITAT VS NICHE Factors that influence the sizes of populations and explore the ecological reasons behind population fluctuations. Biotic Component: LIVING component that affects the population of another organism, or the environment a. Producers b. Consumers HABITAT: physical location where c. Decomposers members of the population live Abiotic Component: NON-LIVING NICHE: all of the resources required chemical of the environment that for survival, growth, and affect living organisms and the reproduction. functioning of ecosystems. TERRESTRIAL BIOMES a. Water b. Atmosphere ecosystems with distinctive c. Temperature communities of life and is found in d. Soil land. It exist because of the e. Sunlight variations of light, temperature, f. Wind and moisture across the biosphere PEOPLE & EARTH’S ECOSYSTEM TEMPERATE DECIDUOUS FOREST: warm summers, cool winters, and consistent rainfall. ✓ Occurs where there is sufficient moisture to support the growth of large trees. Groundwater can be temporarily unavailable if the soil freezes on very cold winter days. Characterized by: Broadleaf deciduous trees distinct annual rhythm in which trees POLAR ICE: COLDEST T. biomes. drop leaves and become dormant Temp: 0°C in winter, then produce new leaves in spring. Known for barren landscapes, glaciers, and huge ice sheets. TEMPERATE GRASSLAND: It has hot Nunataks: covered in ice with some summers, and cold winters, and is ice-free moderately moist. Marine algae called phytoplankton: tropical savanna but they found in primary producers in the polar ice. cold winter temp. Key to persistence: seasonal drought, occasional fires, and TUNDRA: its extreme coldness and grazing by large mammals, all of dryness(extremely low precipitation. which prevent woody shrubs from still a wet place because water invading and becoming established. evaporates slowly) animals have thick fur. CHAPARRAL: also called Mediterranean shrubland. Permafrost: a layer of permanently frozen ground below the surface. Characterized by: mild, rainy winters and long, hot, dry summers are dominated by this biome. TAIGA: LARGEST T. Biomes also called It has hot and dry summers and northern coniferous forest or boreal cool and moist winters. forest. found in cool high elevations in more temperate latitudes. There is a combination of environmental stresses in Soil is usually thin, nutrient-poor, and chaparral: acidic but evergreen trees are abundant here. only some mammals a. Aridity and birds stay year-round. b. short growing season, TEMPERATE RAINFOREST: also called c. low-nutrient soil, and frequent temperate coniferous forest. fires. mild winters, cool summers, and d. Plants are resistant to fire and abundant rain drought thrive; some shrubs have They are common in coastal strands of dense, spiny shrubs with areas that have mild winters and tough evergreen leaves heavy rain. Life includes large evergreens, amphibians, mammals, and fish. PEOPLE & EARTH’S ECOSYSTEM DESERT: DRIEST T. Biomes Its plants store water and most animals are active at night Characterized by: low & unpredictable precipitation. TROPICAL SAVANNA: a grassland with scattered individual tree. Cool&Dry, Hot&Dry, Warm&Wet. are low in nutrients, due in part to their porosity. TROPICAL RAINFOREST: is found in areas near the equator, where rainfall is abundant, and the dry season lasts no more than a few months. It is warm and wet. Characterized by: lush jungles and has the greatest diversity of species of all communities. PEOPLE & EARTH’S ECOSYSTEM Human Evolution f. foramen magnum migrated under the Human evolutionary process began skull, a more anterior position; from the theory of primates of genus and Homo. g. the pelvic region: shortened and widened to keep the ANATOMICAL CHANGES center of gravity stable while 1. BIPEDALISM walking. - Basic adaptation of the hominid. Main cause of skeletal changes Theories why evolution favored the adaptation of bipedalism: 1. liberated the hands for reaching ✓ This made the birth canal smaller and carrying food. and had significant effects on the 2 saved energy during movement process of human birth. 3. enabled running and hunting for ✓ The smaller birth canal limits the long distances. brain size it can accommodate to 4. enhanced the field of vision; and get out. 5. helped avoid hyperthermia ✓ Brain growth increases after birth, because it reduced the surface nurtured by the mother. area exposed to direct sun, ENCEPHALICATION Skeletal changes: a. Femur slightly more angular ▪ The larger brain size allows position to shift the center of gravity humans to learn from each other toward the geometric center of the and pick up language at a body. young age. The parts of the brain responsible for language and b. Knee and ankle joints social behavior, like the temporal increasingly robust to support lobes and prefrontal cortex, have weight better. grown larger in humans. c. Human vertebral column – S-shaped and the lumbar vertebrae became shorter and wider to support the increased weight on each vertebra in the upright position. d. big toe moved into alignment with the other toes to help in walking forward. e. arms and forearms are shortened relative to the legs making it easier to run. PEOPLE & EARTH’S ECOSYSTEM ▪ The increase in brain size o Meaning: female humans are (encephalization) in humans is fertile year-round. linked to the consumption of meat and starches, as well as the development of cooking. Additionally, there is a theory that human intelligence increased as a response to the need to solve complex social problems. The smaller jaw (mandible) and jaw muscle attachments in humans allowed more space in the skull for the brain to expand and grow larger. ULNAR OPPOSITION Thumb opposition This feature is unique to the genus Homo. This trait facilitates precision and power grip of the human hand. Other changes…. 1. increased importance on vision 2. rather than smell. 3. longer developmental period SEXUAL DIMORPHISM for o two sexes of the same species 4. the young. differ in characteristics aside from their sex organs. 5. higher infant dependency. o increased emphasis on pair 6. a smaller gut. bonding for prolonged child- rearing. 7. faster basal metabolism. o Important physiological change r/t sexuality in humans was the 8. loss of body hair. evolution of hidden estrus. 9. evolution of sweat glands. 10. change in the shape of the 11. dental arcade from being u- 12. shaped to being parabolic 13. development of a chin (found in Homo sapiens alone). development of styloid processes; and development of a descended larynx PEOPLE & EARTH’S ECOSYSTEM RECENT ANCESTRY Recent humans were more widespread Gracile Australopithecines ✓ Small braincases (400 to 500 DENSITY AND DISTRIBUTION cc) Population density – numbers of ✓ Walked on 2 legs individuals of a species per unit area ✓ Female 1 meter tall or unit volume of a habitat. ✓ Males 1.5 meter Robust Australopithecines Population dispersion – pattern of ✓ Small brained dispersal of individuals across an ✓ Larger than gracile area of interest. ✓ Large bony crest ✓ Jaw muscle attachments Demography is the statistical study of ✓ Bipedal a population, such as its, Archaic humans, Genus Homo a. density, ✓ All African ✓ H. habilis b. its distribution. ✓ 600 cc brain ✓ Teeth and jaw smaller than in c. and its rate of growth. Australopithecus Demography is dependent on ✓ Taller mortality patterns and age ✓ Less sexually dimorphic in size. Modern Humans distribution. ✓ Last 100,000 years FACTORS THAT AFFECT POPULATION ✓ Biggest brain SIZE ✓ 2000 cc Cro-Magnon ✓ Today, about 1200 cc BIRTH RATE: Number of individual ✓ Higher foreheads produced per unit time ✓ Flatter faces with a prominent nose BIRTHS AND MIGRATION: population increase population size. THE LAST SURVIVOR DEATH RATE: number of deaths per Modern Homo sapiens descended unit of time from multispecies radiation of African DEATHS AND MIGRATIONS: out of the hominids. population the population size. Many species co-existed at one time (estimated to be at least 5 species). Current evidence of human evolution suggests that there was interbreeding with other hominins, suggesting that the path was web-like and non- linear. Paleontological agreement on this. H. sapiens are descendants of some or all the H. ergaster/H. erectus This graph tells us that, most penguins group of die in their first year of life. species How and where did modern need to determine what percent humans arise? of individuals survive to reproductive age because it only they can Archaic humans were certainly in influence the size of the next Africa. generation. PEOPLE & EARTH’S ECOSYSTEM Type I - species that invest much Equilibrium species tend to show energy caring for young have logistic growth low death rates early in life. Most Their population size is near the individuals survive to reproduce carrying capacity They typically reach their Type II - species have an equal reproductive age slower than probability of dying at any age. opportunistic species, have longer lives, and have received Type III - Species invest little extended parental care energy in raising their young have high death rates among Birds, large mammals, and species offspring. Few individuals survive with type I or type II survivorship to reproductive age curves are often equilibrium species Age structure (distribution Exponential Growth of age classes) The pattern of population Age structure (distribution of age growth depends upon two classes) aids in determining if a primary factors: population is growing, stable, or 1. The biotic potential; and declining 2. Resource availability. NATURAL SELECTIONS INFLUENCE ON Factors that Regulate POPULATION Population Size Density-dependent Factors Thomas Malthus' writing, "An Essay 1. The effects of density-dependent on the Principle of Population" was factors one of Charles Darwin's inspirations Increase as the population density when he thought of "Natural rises. Selection 2 They result from interactions between Meaning: populations grow in organisms. geometric progression while food ✓ competing among each other for production grows in arithmetic space, nutrients, food progression. or mates ✓ spread of disease is easier with higher population density and the risk of predation Factors that Regulate Population Size Density-independent Factors 1. Density-independent factors exert effects that are unrelated to population Opportunistic species tend to show density exponential growth. ✓ Natural disasters, such as They are typically small organisms this fire, might eliminate that reproduce at an early age, population in an area have short life spans, and have without regard to population many offspring that receive density little parental care Weeds, insects, and many species with type III survivorship curves have opportunistic life histories PEOPLE & EARTH’S ECOSYSTEM Variation of Birth and Death Rates Worldwide Increase in population - countries with more individuals below reproductive age than are in their reproductive years. Decrease in birth rates - tend to decline as economic development progresses because of family planning programs and opportunities for women outside of the home. POPULATION GROWTH DEPENDS UPON THE REPRODUCTIVE CHARACTERISTICS OF THE POPULATION: 1. Number of offspring per reproduction 2. Chances of survival until reproductive age 3. Frequency of reproduction 4. Age at which reproduction begins WILL HUMAN POPULATION CONTINUE TO GROW EXPONENTIALLY? Overpopulation and Extinction 2 causes of overpopulation 1. Population size 2. Resource consumption The probability that a species will become extinct depends upon three primary factors: Size of Geographic Range Degree of Habitat Tolerance Size of Local Populations