The Final Examination

Transcription

1 The Final Examination 2 P.M. - 3:50 P.M. Tuesday, Dec. 9, 2008 Location: ED

2 Study Session This Sunday ~ 2:00 & 6:30 NS Spring Term Class Biology 370 Environmental Science The course examines the issues of humans in ecological systems. Final Examination ~40 Questions: ~5 Exam I ~35 Populations, Communities, and Ecosystems 2

3 Final Examination Study Hints: Every day ~ 40 minutes Study Group Start NOW! Don t Delay! Community Ecology Characteristics 1. Species Diversity and Relative Abundance 2. Prevalent Form of Vegetation 3. Community Stability (?) 4. Trophic Structure Community Ecology Characteristics 1. Species Diversity and Relative Abundance Community A :100 (1) 60 (2) 25 (3) 10 (4) Community B : 50 (1) 30 (2) 12 (3)

4 Species Area Curve In general, the larger the area, the greater the number of species. Community Ecology Characteristics 2. Prevalent Form of Vegetation - Ecologists examine the dominant species, its vertical and horizontal structure Vertical Structure Horizontal Structure Tropical Rainforests have four layers: EMERGENT LAYER The tallest trees are the emergents, towering as much as 200 feet above the forest floor with trunks that measure up to 16 feet around. Most of these trees are broad-leaved, hardwood evergreens. Sunlight is plentiful up here. It is hot, but not humid and very windy at times. The trees have mushroom shaped crowns. Animals found are eagles, monkeys, bats and butterflies. 4

5 Tropical Rainforests have four layers: CANOPY LAYER This is the primary layer of the forest and forms a roof over the two remaining layers because the trees are so close together. Most canopy trees have smooth, oval leaves that come to a point. Most of the trees are also covered by other plants called epiphytes. 90% of the animals live in this layer. Many animals live in this area since food is abundant. Those animals include: snakes, toucans and tree frogs. Some of these animals never go down to the forest floor. Tropical Rainforests have four layers: UNDERSTORY LAYER Little sunshine reaches this area so the plants have to grow larger leaves to reach the sunlight. The plants in this area seldom grow to 12 feet. Many animals live here including jaguars, red-eyed tree frogs and leopards. There is a large amount of insects here. Tropical Rainforests have four layers: FOREST FLOOR It's very dark down here. Almost no plants grow in this area, as a result. Since hardly any sun reaches the forest floor things begin to decay quickly. A leaf that might take one year to decompose in a regular climate will disappear in 6 weeks. Giant anteaters live in this layer. 5

6 Temperate Forests have three layers: Canopy Layer Understory Layer Forest Floor Community Ecology Characteristics 3. Community Stability (?) Disturbance Ecology Discrete events in time that disrupts ecosystem, community, or population structure and changes resources, substrates, or the physical environment. 6

7 Disturbance Ecology Examples: Floods Wildfires Ice Flows Hurricanes Wind and ice storms Periodic disturbances in forests, shrublands, grasslands, and wetlands are part of ecological systems; as natural of an environmental factor as snow, wind, or rain. Pacific NW Forests 7

8 Community Ecology 4. Trophic Structure Characteristics Feeding Level ; the categories of organism in a community, and the position of an organism in a food web, defined by the organism s sources of energy; includes producers, primary consumers, secondary consumers, etc. Trophic Structures Food Webs Complex Interactions A food web shows the actual feeding relationships in a community, including its many interconnecting food chains. 8

9 Food Webs Complex Interactions Food Chains Linear Interactions A food chain is a linear feeding relationship with just one representative at each trophic level. Different ecosystems have radically different food chains. Natural communities rarely contain well-defined groups of primary, secondary, and tertiary consumers. Biological Magnification 9

10 Food Webs Complex Interactions Habitat Change is Constant Habitat Ecology Species and Habitat Interrelationships Populations are a reflection of both the quantity, quality and location of habitats. 10

11 Chapter Reading Chapter # 28: How Do Ecosystems Work? Pg Ecological Levels of Organization - A Pyramid of Interactions - Species Populations Communities Ecosystems Biogoegraphical Realms Biosphere (Earth) An Ecological System? In the discipline of ecology, the word Ecosystem is an abbreviation of the term, Sir Arthur Tansley ( ) ecological system the basic unit in ecology. It first appeared in a 1935 publication by the British ecologist Arthur Tansley (Tansley, 1935). However, the term had been coined already in 1930 by Tansley's colleague Roy Clapham, who was asked if he could think of a suitable word to denote the physical and biological components of an environment considered in relation to each other as a unit. Tansley, A., 1935, The use of vegetational concepts and terms. Ecology, v. 16, p

12 Ecological Levels of Organization Ecosystems Ecosystem An array of species, populations, and communities, AND their physical environment, interacting through a flow of energy and a cycle of nutrients. An Ecological System? Composition: Structure: Function: What is here/there? How is the system built? How is it distributed? How does the system operate? What it does. An Ecological System? Components of an Ecosystem: Sir Arthur Tansley ( ) Abiotic (non-living) and Biotic Components Physical Components Species Water Populations Nutrients Communities Topography Weather Competition and Predation Disturbances 12

13 Energy and the Laws of Thermodynamics Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy. Kinetic energy Entropy Entropy Potential energy Energy and the Laws of Thermodynamics The 1 st Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another. Isaac Newton ( ) Energy and the Laws of Thermodynamics The 2 nd Law of Thermodynamics: "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state." In energy transfer, some energy will dissipate as heat. The flow of energy maintains order and life. Isaac Newton ( ) 13

14 Limits - Laws of Thermodynamics The 10% Rule Consumers Consumers Producers Greater than 90% of the available energy is lost in the form of heat energy at each level Limits: Thermodynamics and Pyramids of Biomass and Numbers Consumers Producers Decomposers Energy flows through ecosystems Nutrients cycle through ecosystems Global Primary Productivity 14

15 Nutrient Cycles Nutrients are elements and small molecules that form the chemical building blocks of life. Macronutrients are required by organisms in large quantities. Examples: water, carbon, hydrogen, oxygen Micronutrients are required only in trace quantities. Examples: zinc, molybdenum, iron, selenium Nutrient Cycles Nutrient cycles (or biogeochemical cycles) describe nutrient pathways between communities and abiotic components of ecosystems. Nutrient Reservoirs are sources and storage sites. Major reservoirs are usually in the abiotic environment. Nutrient Cycles The Carbon Cycle 15

16 Nutrient Cycles The Water Cycle Nutrient Cycles The Nitrogen Cycle World Climate: Seasons Earth s Curvature Cause of Seasons Amount of sunlight per area decreases as you move away from the equator. Orbit of the earth around the sun and the tilt of the earth give rise to seasons 16

17 World Climate: Currents Warm air rises at the equator. Cool air descends. Moves water around the Earth. Rotation of earth changes wind patterns.. World Climate: Oceans Water moves heat Moderates climate Examples: The well-known Gulf Stream in the Atlantic and its counterpart in the Pacific, the Kuroshio Current, are strong currents that carry heat northward from the tropics. California current along Oregon Coast (cool water) World Climate Patterns Sunlight, Temperature, Moisture, and Geology 17

18 Effect of Mountains on Temperature, Moisture, and Vegetation Effect of Altitude on Vegetation The Rainshadow Effect Kamloops, British Columbia Effect of Rainfall & Temperature on Vegetation Ecological Levels of Organization -Biomes - Biome Large regions of land and water that are characterized by similar habitat conditions and community structure. 18

19 World Biomes A Finnish word for treeless plain 1/5 of the Earth s land surface World Biomes Tundra - Average temperature below freezing. - Poor drainage - Short growing seasons - Low precipitation (<25cm/yr) - Permafrost (~1.5 ft below surface) Two types of Tundra: A) Arctic Tundra - Short growing seasons - Low productivity - Extensive peat bogs B) Mountain Tundra World Biomes Tundra - Islands of mountaintop habitat - Shorter daylengths 19

20 World Biomes Boreal Forest (Taiga) - Conifers (cone-bearing) trees - The Northern Coniferous Forest - Taigas ( swamp forests ) - A Russian word meaning mountain - Glaciated areas - Cold, dry winters - Scattered trees - Short growing season World Biomes Temperate Rain Forest - High Species Diversity in temperate climate - > 125 inches/yr rainfall - Long-term intervals between disturbances World Biomes Temperate Deciduous Forest - Broadleaf trees (Ash, Beech, Maples, Oaks, Birch, Chestnut, Elm) - More diverse than Coniferous Forests. - Freezing temperatures during winter. - Leaf loss due to freezing damage. - In SW U. S. associated with riparian areas. - Lost as farmers cleared land for agricultural production. 20

21 World Biomes Temperate Grasslands - Low Rainfall - Short and Long grass prairie - Deep, fertile soils - Maintained by the RainShadow World Biomes Temperate Grasslands Historically covered 43% of U. S. land area. - Fire and herbivores are important components in maintaining structure and function of the grassland system (a disturbance). World Biomes Chaparral - Found on west coast of continents (Mediterranean Climate) - Hot summers, cool wet winters - Usually above freezing temperatures - Shrubs are most prevalent species 21

22 World Biomes Deserts < 10 cm/year - Rainfall is brief but heavy - Relatively low productivity - Vast extremes in air temperatures World Biomes Deserts 1/3 of the world s land surface is arid or semiarid Cold, high mountain deserts Hot deserts World Biomes Tropical Rain Forests Highest Species Diversity Most productive biomes Annual mean temperature 25 C, humidity > 80% Litter does not accumulate, rapid decomposition of organic matter; soils are weathered and nutrient-poor 22

23 World Biomes Oceans, Estuaries, and Wetlands Biologically diverse systems World Biomes Coral Reefs Some of the most biologically diverse systems on Earth, aquatically (in water) or terrestrially (on land). Biogeographical Realms Realms: Six immense land areas and 1 aquatic area, each with distinctive species of plants and animals. W. L. Sclater 1858 (Bird distributions) A. R. Wallace 1876 (Mammal distributions) 23

24 Atmospheric Change The Keeling Curve Biology 370: Environmental Science 24