Bio – Lecture 2 PDF

9/8/24 1 ECOLOGICAL CONCEPTS, ECOSYSTEM COMPONENTS, AND BIOMES 2 ECOLOGICAL CONCEPTS 3 ECOLOGY The word “ecology” was first termed in 1866 by Ernst Haecker from two Greek words: oikos – me...

9/8/24 1 ECOLOGICAL CONCEPTS, ECOSYSTEM COMPONENTS, AND BIOMES 2 ECOLOGICAL CONCEPTS 3 ECOLOGY The word “ecology” was first termed in 1866 by Ernst Haecker from two Greek words: oikos – meaning “house” logos – meaning “the study of” Ecology: Scientific study of the relationship between organisms and their environments. Environment: All the external physical, chemical, and biological factors that directly affect survival, growth, metabolism, activity, development, and reproduction of organisms. 4 HISTORICAL PERSPECTIVES Natural History: Qualitative, descriptive studies of the form, function, behavior, and distribution of plants and animals. Quantitative Biological Inquiries: Systematic measurements of the environment; develop hypothesis and theories about ecological functioning. 5 HISTORICAL PERSPECTIVES Among scientists, a general disinterest in natural history was brought about by the rise of technology, but natural history is still important today. WHY? 6 HISTORICAL PERSPECTIVES Natural history data are essential for testing theories in ecology, evolution and conservation biology. 1 6 Natural history data are essential for testing theories in ecology, evolution and conservation biology. Natural history data set realistic boundaries on theories. ®Don’t need a theory that applies to things that don’t occur in the real world ®Natural history data let us know what a theory has to deal with and what it doesn’t Need a balance between natural history and quantitative studies. 7 LEVELS OF THE ORGANIZATION OF MATTER ORGANISM: Fundamental functional unit in ecology: ® Individual organisms interact directly with the environment and with each other ® Changes in higher levels of biological organization occur due to changes in the organisms that make them up 8 An organism is an individual life form. ○ 9 LEVELS OF THE ORGANIZATION OF MATTER POPULATION: A group of organisms of the same species occurring together in the same place and time. COMMUNITY: More than one population occurring together and interacting in a particular area/environment. ECOSYSTEM: A community of living things (biotic components) plus the non-living (abiotic) factors of a particular environment. 10 11  10 A population includes all members of a species that live in the same area at the same time. ○ 11 The biological community is made of all the populations living and interacting in one area. ○ 12 An ecosystem includes the biological community and surrounding physical environment. ○ 13 Levels of the Organization of Matter 14 REALM OF ECOLOGY 15 LEVELS OF THE ORGANIZATION OF MATTER Although organisms are the fundamental functional unit in ecology, they’re not usually a basic unit of study of ecologists. Most ecologists study ecosystems. WHY? Ecosystems are where biotic and abiotic factors are first studied together. Two basic types of ecosystems: ® Those of the lithosphere Þ terrestrial ® Those of the hydrosphere Þ aquatic 16 ECOSYSTEM COMPONENTS LIVING AND NON-LIVING 17 ABIOTIC COMPONENTS (NON-LIVING) Physical Factors: Temperature, light, humidity, precipitation, wind and water currents Weather: Day-to-day variations in atmospheric conditions Climate: Average prevailing weather conditions in an area over a relatively long time (30+ years): temperature, precipitation, sunlight, 17 Climate: Average prevailing weather conditions in an area over a relatively long time (30+ years): temperature, precipitation, sunlight, winds Macroclimate: Global, regional, and landscape level Microclimate: Small area (example: a community of organisms underneath a fallen log) 18 GLOBAL CLIMATE PATTERNS Determined by solar energy and the planet’s movement in space. Causes temperature variations, which drive evaporation and the circulation of air and water. Causes latitudinal variations in climate. 19 ABIOTIC COMPONENTS (NON-LIVING) Of these physical factors, which ONE is considered THE most important? Moisture WHY? ® Alone (or in conjunction with temperature) it is probably the most important physical factor affecting the distribution and pattern of terrestrial vegetation. ® Many/most adaptations of plants and animals are related to moisture: acquiring it; holding onto it; getting rid of it. 20 21 ABIOTIC COMPONENTS (NON-LIVING) Temperature ® Vast majority of life exists within a rather narrow band of temperature. ® Variation tends to be less in water than on land. Light Ecologically, there are three important characteristics of light to organisms: ® Quality (wavelength or color) ® Intensity 22  ® Quality (wavelength or color) ® Intensity ® Duration (day length) 22 ABIOTIC COMPONENTS (NON-LIVING) Wind and Water Currents ® Prevailing winds, major determinants of climate. ® Climate is also modified locally by topography and large bodies of water. What makes the winds blow? Solar energy ® thermal patterns + Earth’s rotation Þ wind (and water) currents Chemicals ® organic: contain C and H ® inorganic: do not contain C or H or either 23 ECOSYSTEM FUNCTION Ecosystem function: Interconnections or relationships among ecosystem components, abiotic and biotic. Two major ecosystem functions: ® Cycling of chemicals ® Flow of energy 24 LAWS OF MATTER AND ENERGY Govern the function of all matter at any level of organization. Are empirical laws: based on observation and experimentation. 25 LAW OF CONSERVATION OF MATTER (ENERGY) Matter (energy) can neither be created nor destroyed on Earth, but merely changed from one form to another. Matter is finite in our closed system and therefore matter which is essential to life must be cycled. 26  essential to life must be cycled. Matter is cycled by biogeochemical cycles. 26 BIOGEOCHEMICAL CYCLES Biogeochemical cycles: Flow of chemicals from abiotic components of an ecosystem to biotic components, then back to the abiotic components. Three basic types of biogeochemical cycles: Gaseous: Atmosphere is the primary reservoir Examples: C, O, N Sedimentary: Chemicals move from land to ocean and back again to land Example: Phosphorous Hydrological: Cycling of water 27 NUTRIENTS Nutrients: Elements and molecules necessary for growth and development of living organisms. Macronutrients: Materials needed in large amounts; constitute 95% of mass of all living organisms. ® Examples: C, O, H, N, P Micronutrients: Materials needed in small or “trace” amounts. ® Examples: Fe, Mg, Cu, I, Zn, Co, etc. 28 BIOTIC COMPONENTS (LIVING) Producers (plants, or autotrophs) Autotrophs (self-feeding) utilize solar energy to photosynthesize organic chemicals from CO2 and HOH. Macroconsumers (animals, or heterotrophs) Heterotrophs cannot manufacture their own food, but must feed on other organisms.  Heterotrophs cannot manufacture their own food, but must feed on other organisms. ® Herbivores: Consume plants (primary consumers) ® Carnivores: Consume other animals (secondary/higher consumers) ® Omnivores: Consume plant and animal food items ® Detritus Feeders (Detritivores): Consume dead matter 29 BIOTIC COMPONENTS (LIVING) Microconsumers (decomposers): Decomposers obtain food from dead organic matter (detritus) through decomposition. The detritus food chain (both detritivores and decomposers) is the major pathway of energy flow in most ecosystems. 30 BIOMES 31 BIOMES: TERRESTRIAL AND AQUATIC Biomes: Major life zones characterized by vegetation type (terrestrial biomes) or physical environment (aquatic biomes). Biomes are affected not just by average temperature and precipitation, but also by the pattern of temperature and precipitation through the year. 32 TERRESTRIAL BIOMES 33 34 35 TERRESTRIAL BIOMES Major terrestrial biome types (eight, nine, and varies; WWF recognizes 14): Forests: Tropical forest Temperate forest Conifer forest (taiga and boreal forest) Grasslands: Tropical savanna Temperate grasslands Chaparral (shrublands) 36 37  Temperate grasslands Chaparral (shrublands) Tundra (arctic and alpine) Deserts 36 37 TERRESTRIAL BIOMES General Features of Terrestrial Biomes: Often named for dominant vegetation. Reflect adaptations of dominant plant life forms. Usually grade into each other, without sharp boundaries. An area of intergradation, called an ecotone, may be wide or narrow. 38 VEGETATION CHANGES Plants in cold regions have traits to limit heat & water loss. Winter dormancy (drop leaves), smaller size, evergreens have needles. Plants in dry areas must lose heat and conserve water. No leaves, water storage, nocturnal activity. Plants in rainforests must get light and remove water. Broad leaves, drip tips, radiate heat. 39 TERRESTRIAL BIOMES Vertical layering is an important feature of terrestrial biomes, and in a forest it might consist of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer. Layering of vegetation in all biomes provides diverse habitats (microhabitats) for animals. Biomes are dynamic and usually exhibit extensive patchiness. Terrestrial biomes can be characterized by distribution, precipitation, temperature, plants, and animals. 40 FOREST BIOMES 41 World Distribution of Forests 42 40 41 World Distribution of Forests 42 TROPICAL FOREST Equatorial and subequatorial regions. Tropical rain forests, rainfall is relatively constant. Tropical dry forests, precipitation is highly seasonal. Temperate: 25–29°C. Vertical layering. Most diverse terrestrial biome (biodiversity). 43 TROPICAL RAIN FOREST Climate: Precipitation over 150 cm/yr, but still have rainy and dry seasons. Warm humid year-round climate à 80 °F. Long growing season. Distribution: 23.5 °N to 23.5 °S latitude à Tropic of Capricorn to Tropic of Cancer. About 2% of the Earth’s surface; major determinants of global climate. Three chunks: S. & C. America, C. Africa, SE Asia. Structure: Complex; stratified layers. Great diversity: 50-80% of terrestrial species. Relative Productivity: Greatest among terrestrial systems; unlimited by temperature and moisture. 44 45 46 TROPICAL RAIN FOREST Broadleaved evergreen trees. Huge biological diversity; specialized niches (microhabitats). Much of animal life found in canopy layer. Stratification of life in different tree layers increases niche partitioning. Paradox à great diversity but very poor soils. Rapid recycling of nutrients. 47  Paradox à great diversity but very poor soils. Rapid recycling of nutrients. Little nutrients stay in soil; most taken back into plants. Dense forest limits wind à plants rely on animal pollinators. 47 48 TEMPERATE BROADLEAF/SEASONAL FOREST Midlatitudes in the Northern Hemisphere, with smaller areas in Chile, South Africa, Australia, and New Zealand. Large amount of precipitation in all seasons. Winters average 0°C, while summers are hot and humid (near 35°C). Significant seasonal changes. Vertical layering. Deciduous trees; thick layer of leaf litter. Mammals, birds, amphibians, reptiles, insects. 49 TEMPERATE BROADLEAF/SEASONAL FOREST Forest ecosystems dominate the wetter regions of the temperate zone. Deciduous forest covered large area of Europe and China, but mostly converted to croplands, only exist in eastern China. North America, deciduous forests consist of a number of associations (next slide). Southern Hemisphere, temperate evergreen forest becomes predominant. Asiatic broadleaf forest found in eastern China, Japan, Korea is similar to the North American deciduous forest. 50 51 52 NORTHERN CONIFEROUS FOREST (TAIGA/BOREAL) Taiga/boreal forests span northern North America and Eurasia; largest terrestrial biome on Earth (34%). Lie just below tundra. Precipitation varies. Dominated by coniferous tree species (withstand cold; rapid growth in summer). 53  Dominated by coniferous tree species (withstand cold; rapid growth in summer). Low temperatures ® low decomposition; high soil acidity. 53 NORTHERN CONIFEROUS FOREST (TAIGA/BOREAL) In summer soil is waterlogged ® muskegs Muskeg: North American swamp or bog consisting of a mixture of water and partly dead vegetation. Winters are cold and long while summers may be hot (e.g., Siberia ranges from –50°C to 20°C). Pine, spruce, fir. Cone shape protects breakage from snow. Moose, bear, migratory birds, Siberian tigers. 54 55 56 GRASSLAND BIOMES TUNDRA, TROPICAL SAVANNA, TEMPERATE 57 World Distribution of Grasslands 58 TUNDRA Arctic regions. Alpine tundra exists on high mountaintops at all latitudes. Precipitation is low in arctic tundra, greater in alpine tundra. Winters are long and cold (below –30°C) while summers are relatively cool (less than 10°C). Permafrost; produces poor drainage. Spongy mat of vegetation: mosses, lichens, grasses. Reindeer, musk, oxen, lemmings (migratory animals), Arctic hare. Common breeding area b/c predators (snowy owls, Arctic foxes, Arctic wolves, and polar bears) are visible. 59 TUNDRA Distribution: 60 – 75 °N latitude à northern North America, Asia, Greenland. About 20% of the Earth’s surface. Structure: 59 About 20% of the Earth’s surface. Structure: Simple: Spongy mat of vegetation: mosses, lichens, grasses. Even trees are less than knee high. Relative Productivity is low; limited by temperature. Reindeer, musk, oxen. 60 61 62 Arctic Tundra Distribution 63 64 (TROPICAL) SAVANNA/SEASONAL FOREST Equatorial and subequatorial regions. Precipitation is seasonal. Warm year-round (24–29°C) but more seasonally variable than the tropics. Moderate rainfall; prolonged droughts. Fire-adapted plants. Grasses and forbs (occupy the niche of cacti). Zebras, lions, hyena, grazing and browsing herbivores, etc. 65 66 (TROPICAL) SAVANNA/SEASONAL FOREST Herbivore co-existence: Minimize competition by resource partitioning. Examples: Giraffes eat leaves from tree tops. Elephants eat leaves and branches further down. Gazelles & Wildebeests eat short grasses. Zebras eat longer grass & stems. 67 CHAPARRAL Midlatitude coastal regions on several continents. Rainy winters and dry summers. Summer hot (30°C+) while fall, winter, and spring are cool (10– 68 69 67 Rainy winters and dry summers. Summer hot (30°C+) while fall, winter, and spring are cool (10– 12°C). Shrubs, grasses, herbs (fire-resistant). Insects and small mammals. 68 69 TEMPERATE GRASSLANDS Found on many continents. Precipitation is highly seasonal, erratic; 25-45 cm/yr – enough to grow grass; Semiarid. Winters cold (often below –10°C) and dry summers hot (often near 30°C) and wet. Grasses and forbs adapted to fire and drought. Medium to high primary productivity; high turnover of grasses; rich soils. Most agricultural land is in grassland biomes. Bison and wild horses, ferrets, prairie dogs, owls, etc. 70 71 DESERT BIOMES 72 DESERTS Deserts distributed 30° N/S of equator and in interior of continents. 30% of Earth’s surface. Precipitation