Why is ecology important?

Transcription

1 Chapter 1 Overview Why Studying Ecology and Environmental Science Levels of Studying Ecology Differences among Ecological and Environmental Studies Biogeography and species distribution 1 Why is ecology important?

2 What is? 3 Ecology is: A science and as such is concerned with: Attempting to describe and explain as objectively as possible patterns and processes that occur in the physical world Also attempts to make predictions about future events based on past history and current circumstances 4 2

3 Easter Island 5 Easter Island 6 3

4 It is important to clarify the difference between Ecology and Environmental Science Ecology, is the scientific study of the distribution and abundance of organisms, while environmentalism, advocacy for the protection or preservation of the natural environment. To address environmental problems, we need to understand the interactions of organisms and the environment where. The science of ecology provides that understanding. Ecology provides a scientific context for evaluating environmental issues 7 Environmental science It can help us avoid mistakes made by past civilizations. Can we act more wisely to conserve our resources? The lesson of Easter Island (Chile): people annihilated (destroyed) their culture by destroying their environment. Easter Island, also called Rapa Nui, was annexed by Chile in Easter Island is small, but its story is a dark one that suggests what can happen when people use up the resources of an isolated area. New data suggest that people first arrived about 800 years ago, certainly played a role in the loss of trees (Deforestation), and the rats that arrived with the Polynesians were evidently responsible for eating seeds of the palm trees, preventing regeneration. 8 4

5 Overview of Ecology Ernst Haeckel, The Founders of the term ECOLOGY was the German zoologist, in 1866 Haeckel 1870 By ecology we mean the body of knowledge concerning the economy of nature the investigation of the total relations of the animal both to its inorganic and organic environment Ernst Haeckel 9 Definitions of Ecology Tansley 1904 (Ecology is) Those relations of plants, with their surroundings and with one another, which depend directly upon differences of habitat among plants. Elton 1927 Ecology is the new name for a very old subject. It simply means scientific natural history. Andrewartha 1961 Ecology is the scientific study of the distribution and abundance of organisms. 10 5

6 Definitions of Ecology Krebs 1972, 2008 Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms. Townsend et al Ecology is the scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance. 11 Ecology Ecology (from the Greek oikos, home, and logos, study) Ecology is the scientific study of the interactions between organisms and the environment Interactions determine both the distribution of organisms and their abundance Ecological interactions occur at a hierarchy of scales that ecologists study, from single organisms to the globe 12 6

7 Ecology is an interdisciplinary science 13 Ecology is: A science of dependency A probabilistic science 14 7

8 Levels (subfields) of Ecology: 1. Organismal ecology: Studies how an organism s structure, physiology, and (for animals) behavior meet the challenges posed by the environment (Adaptation). 2. Population ecology: Concentrates mainly on factors that affect how many individuals of a particular species live in an area (study of one species) 3. Community ecology: Deals with the whole array of interacting species in a community (Biodiversity) 4. Ecosystem ecology: Emphasizes energy flow and chemical cycling among the various biotic and abiotic components 5. Large scale ecology: Lanndscape ecology: Deals with arrays of ecosystems and how they are arranged in a geographic region Biomes Global Ecology (The biosphere): is the global ecosystem, the sum of all the planet s ecosystems. 15 Galaxies Ecology 2005 Solar system Scale Earth ECOLOGY Ecosystems PHYSIOLOGY Communities Populations Organisms Organs Community ecology Different levels of studying ecology Tissues BIOCHEMISTRY Cells CELL BIOLOGY Molecules Atoms The organizational levels of ecology 16 8

9 What is Environmental Science? Environment (from the French environner: to encircle or surround) can be defined as (1) the circumstances or conditions that surround an organism or group of organisms, or (2) the complex of social or cultural conditions that affect an individual or community 17 BIOGEOGRAPHY 18 9

10 Biogeography Interactions between organisms and the environment limit the distribution of species Biogeography is studying the Factors affecting the distribution of organisms Biogeography is the study of the geographic distribution of organisms throughout the landscape Biogeography provides a good starting point for understanding what limits the geographic distribution of species 19 Species Dispersal Dispersal refers to the process of distribution of individuals within geographic population boundaries Ecological (Adaptive) Dispersal: "why it happens" Movement to new, unused resources (away from parents) Within same habitat Across barrier to new habitat (within range) Successful Dispersal depends on "long distance" transport withstanding unfavorable conditions during travel and upon early arrival establishing a viable population 20 10

11 Kinds of Dispersal Three Kinds of Dispersal Leading to Range Expansion Jump Dispersal long distances over inhospitable habitat example: oceanic islands mostly by volant organisms (flight) ex.: Galapagos Islands Diffusion movement into adjacent habitats as population expands Plants: purple loosestrife, halogeton, storksbill Birds: cattle egret, starlings, house sparrows muskrat, armadillo, nutria (Myocastor coypus) Secular Migration: geological times scale Plants: diversification and spread of flowering plants Animals: spread of camels from North America to S. America and Asia 21 Dispersal Mechanisms Active Dispersal strong fliers annual migrators examples: golden plover (is a shore bird that breeds during the Arctic summer, and then flies to the southern hemisphere during its summer. Passive Dispersal Mechanisms: Plants 22 11

12 مسار هجرة اللقلق " فرينتسي" )باللون االزرق( من المانيا وحتى جنوب أفريقيا وعودتها )باللون البنفسجي( حسبما تم استيعابه من القمر االصطناعي من خالل جهاز االرسال المالزم لجسمها. زوجها " يونس" هاجر الى جنوب اسبانيا )باللون االصفر (. 23 Behavior Why Organisms may not occupy all potentially suitable habitat? Evolution doesn t lead to perfect organisms. Evolution is an ongoing process. Environments change, but it takes a while for organisms to respond

13 Biotic factors Did organisms required for potential community members to colonize may be lacking? Pollinators, prey, predators that limit competition 25 Abiotic factors Are there any Abiotic factors affect distribution? Temperature (range from 0 to 45 C) Water Sunlight Wind (increases heat & water loss) Rocks and soil 26 13

14 Influence of Precipitation and Temperature on Vegetation 27 Relationship Between Height above Sea Level, Latitude, and Vegetation Mountains built by geological processes and thus concentrated in belts of geological activity. Climate changes with elevation and latitude. Soils are generally welldrained and thin. Flora and fauna change with elevation. Historically used as a source of raw materials for human settlements

15 Mountains 29 Aquatic and Terrestrial Biomes Biome is major ecosystem type 30 15

16 Aquatic biomes Cover about 75% of the earth s surface - Wetlands - Lakes - Rivers, streams - Estuaries - Intertidal zones - Oceanic pelagic biome - Coral reefs - Benthos

17 Oligotrophic Lake: Nutrient poor, water is clear, oxygen rich; little productivity by algae, relatively deep with little surface area. 33 Eutrophic lake: nutrient rich, lots of algal productivity so it s oxygen poor at times, water is murkier قاتم often a result of input of agricultural fertilizers 34 17

18 Rivers and Streams: Organisms need adaptations so that they are not swept away by moving water; heavily affected by man changing the course of flow (E.g. dams and channel-straightening) and by using rivers to dispose of waste. 35 Wetlands: includes marshes, bogs, swamps, seasonal ponds. Among richest biomes with respect to biodiversity and productivity. Very few now exist as they are thought of often as wastelands

19 Estuary: Place where freshwater stream or river merges with the ocean. Highly productive biome; important for fisheries and feeding places for water fowl. Often heavily polluted from river input so many fisheries are now lost. 37 Marine environment with zonation 38 19

20 Intertidal Zone: Alternately submerged and exposed by daily cycle of tides. Often polluted by oil that decreases biodiversity. 39 Coral Reefs: occur in neritic zones of warm, tropical water, dominated by cnidarians (corals); very productive, protect land from storms; most are now dying from rise in global temperatures 40 20

21 Deep-sea vent: Occurs in benthic zone; diverse, unusual organisms; energy comes not from light but from chemicals released from the magma Terrestrial Biomes Biomes are distinguished primarily by their predominant plants and are associated with particular climates. Geographic and seasonal variations in temperature and precipitation are fundamental components. - Tropical forest - Savanna - Desert - Chaparral - Temperate grassland - Temperate deciduous forest - Coniferous forest - Tundra 42 21

22 43 Tropical Forest: Vertical stratification with trees in canopy blocking light to bottom strata. Many trees covered by epiphytes (plants that grow on other plants)

23 45 Tropical Rainforests Annual rainfall of 2,000-4,000 mm relatively evenly distributed

24 Tropical, Dry Forest 47 Tropical Dry Forest 48 24

25 Savanna 49 Tropical Savanna 50 25

26 Desert: Sparse rainfall (< 30 cm per year), plants and animals adapted for water storage and conservation. Can be either very, very hot, or very cold (e.g. Antarctica) 51 Desert 52 26

27 Chaparral: Dense, spiny, evergreen shrubs, mild rainy winters; long, hot, dry summers. Periodic fires, some plants require fire for seeds to germinate. 53 Mediterranean Woodland and Shrubland 54 27

28 Temperate Grassland: Marked by seasonal drought and fires, and grazing by large animals. Rich habitat for agriculture, very little prairie exists in US today. 55 Temperate Grassland Annual rainfall 300-1,000 mm

29 Temperate Deciduous Forest: Mid-latitudes with moderate amounts of moisture, distinct vertical strata: trees, understory shrubs, herbaceous substratum. Loss of leaves in cold, many animals hibernate or migrate then. Original forests lost from North America by logging and clearing. 57 Temperate Forest (Old Growth) Rainfall averages 650-3,000 mm

30 Coniferous forest: Largest terrestrial biome on earth, old growth forests rapidly disappearing, usually receives lots of moisture as rain or snow. 59 Boreal Forest (Taiga) 60 30

31 Tundra: Permafrost (Permanent frozen ground), bitter cold, high winds and thus no trees. Has 20% of land surface on earth. 61 Tundra mm precipitation 62 31