All things come from earth and to earth they all return Menander (342-290 B.C)
Main Questions of this chapter • What is ecology? • What is an ecosystem and its main components? • What happens to matter and energy in an ecosystem and how does that keep us alive?
Core Case Study: Tropical Rain Forests Are Disappearing • Cover about 2% of the earth’s land surface • Contain about 50% of the world’s known plant and animal species • Disruption of rain forest will have three major harmful effects • Reduce biodiversity • Accelerate global warming (burn, less absorption of greenhouse gases) • Change regional weather patterns
Natural Capital Degradation: Satellite Image of the Loss of Tropical Rain Forest
3-1 What Is Ecology? • Concept 3-1 Ecology is the study of how organisms interact with one another and with their physical environment of matter and energy. • Ecology is the study of connections in nature
(a) Eukaryotic Cell Energy conversion Nucleus (DNA) Protein construction Cell membrane Cells Are the Basic Units of Life • Cell Theory (all living things are composed of cells , the smallest and most fundamental unit of life) Eukaryotic cells have: membranes, nucleus and organelles (internal specialized parts)
(b) Prokaryotic Cell DNA (no nucleus) Cell membrane Protein construction and energy conversion occur without specialized internal structures Prokaryotic cell Has membrane No distinct nucleus No specialized internal parts All bacteria consist of a single prokaryotic cell Stepped Art Fig. 3-2, p. 52
Species Make Up the Encyclopedia of Life • Species • 1.75 Million species identified • Insects make up most of the known species • Perhaps 10–14 million species not yet identified
Ecologists Study Connections in Nature Levels of organization • Population • Group of individuals that live in same place • Genetic diversity (variation in a population) • Habitat: place where a population lives • Community • All populations that live in a particular place • Ecosystem • Describes the interaction of a community and their habitats • Biosphere consists of parts of the earth where life is found, in effect the largest ecosystem
Parts of the earth's air, water, and soil where life is found Biosphere A community of different species interacting with one another and with their nonliving environment of matter and energy Ecosystem Populations of different species living in a particular place, and potentially interacting with each other Community Population A group of individuals of the same species living in a particular place An individual living being Organism The fundamental structural and functional unit of life Cell Chemical combination of two or more atoms of the same or different elements Molecule Smallest unit of a chemical element that exhibits its chemical properties Atom Stepped Art Fig. 3-3, p. 52
Size of ecosystems • Range from a puddle of water to an ocean • Do not have clear boundaries • Not isolated from each other • Can be natural or man made
Think about the school in terms of how life can be grouped: • Populations • Communities • Ecosystems
Are insect populations important to the health of human populations? Which group needs the other more? Humans or insects?
Science Focus: Have You Thanked the Insects Today? • Pollinators • Eat other insects • Loosening and renewal of soil • Reproduce rapidly (food source) • Very resistant to extinction, fast evolutionary process
Do you think there is a useless population on earth? Explain your answer by defining the term ‘useless’ first.
Section Check • Q1: Distinguish between a eukaryotic and a prokaryotic cell. Name an example of living organism that has them for each type. • Q3: What % of all living species do we have information on? Which class of organism most likely has the greatest number of species? • Q4: What are the main differences between a population, a habitat and a ecosystem? Name an example of each.
3-2 What Keeps Us and Other Organisms Alive? • Concept 3-2 Life is sustained by the flow of energy from the sun through the biosphere, the cycling of nutrients within the biosphere, and gravity.
What are the 4 majors parts (spheres) of the earth life support system?
The Earth’s Life-Support System Has Four Major Components • Atmosphere • Troposphere – closest, weather, warmth, air • Stratosphere - farther away from surface, ozone • Hydrosphere • Geosphere- includes interior, minerals, oil, soil • Biosphere- all living things in all other spheres
Vegetation and animals Atmosphere Biosphere Soil Rock Crust Natural Capital Lithosphere Mantle Biosphere (living organisms) Atmosphere (air) Core Crust (soil and rock) Mantle Hydrosphere (water) Geosphere (crust, mantle, core) Fig. 3-6, p. 55
Life Exists on Land and in Water • Biomes (land) • regions of earth with one dominant type of environment (Deserts, plains, deciduous forests…) • Aquatic life zones • Freshwater life zones • Lakes and streams • Marine life zones • Coral reefs • Estuaries • Deep ocean
Major biomes along 39th parallel in US Average annual precipitation 100–125 cm (40–50 in.) 75–100 cm (30–40 in.) 50–75 cm (20–30 in.) 25–50 cm (10–20 in.) below 25 cm (0–10 in.) Denver Baltimore San Francisco St. Louis Coastal mountain ranges Sierra Nevada Great American Desert Rocky Mountains Great Plains Mississippi River Valley Appalachian Mountains Coastal chaparral and scrub Coniferous forest Desert Coniferous forest Prairie grassland Deciduous forest Fig. 3-7, p. 55
Three Factors Sustain Life on Earth • One-way flow of high-quality energy beginning with the sun • From sun through food cycle to environment exiting back into space • Dictated by 2nd law of Thermo, high to low quality energy • Cycling of matter or nutrients • Earth is basically closed in terms of matter • Nutrients must be recycled, in seconds or in centuries • Gravity (law of gravity) • How does gravity help sustain life on Earth?
How does gravity help? • Allows earth to hold on to an atmosphere • Allows movement of materials, life on earth
The name of the effect is ______________ How do you think this effects works? Is this effect natural or man-made?
What Happens to Solar Energy Reaching the Earth? • UV, visible, and IR energy (forms of electromagnetic radiation (waves)) • Radiation • Is absorbed by ozone • Is absorbed by the earth • Is reflected by the earth, as heat • Some is trapped in troposphere • The raising heat moves the air , creating wind
Energy flow to/from Earth Solar radiation Reflected by atmosphere Radiated by atmosphere as heat UV radiation Lower Stratosphere (ozone layer) Most absorbed by ozone Troposphere Visible light Heat radiated by the earth Heat Absorbed by the earth Greenhouse effect Fig. 3-8, p. 56
Natural Greenhouse Effect • Energy from sun is reflected back towards space as infrared radiation (felt as heat) • Encounter greenhouse gases (CO2, CH4, No3- and O3) • Causes gas molecules to vibrate more • More vibration greater KE and Heat • Warmer atmosphere and surface
1) What if there was no greenhouse effect? 2) What would happen if the greenhouse effect is increased?
Section Check Q5: How do the stratosphere and the troposphere differ? What are the main benefits humans derive from each? Q8: How are Biomes and Aquatic Life Zones similar? Q9: What are the 3 factors that sustain life on Earth? What the laws that relate to the factor?
Section Check: Green House Gasses Q6: What are greenhouse gases and how do they affect life on the planet? Q10: What is the benefit of the ozone in the troposphere? What would be the result if it were removed? Q11: How is wind generated by solar energy? Q12: How do greenhouse gases keep the earth warm?
3-3 What Are the Major Components of an Ecosystem? • Concept 3-3A Ecosystems contain living (biotic) and nonliving (abiotic) components. • Concept 3-3B Some organisms produce the nutrients they need, others get their nutrients by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms.
Ecosystems Have Living and Nonliving Components • Abiotic : Non-living components • Water • Air • Nutrients • Rocks • Heat • Solar energy • Biotic • Living and once living
Precipitation Oxygen (O2) Carbon dioxide (CO2) Major Biotic and Abiotic components of an Ecosystem Producer Secondary consumer (fox) Primary consumer (rabbit) Producers Decomposers Water Soluble mineral nutrients Fig. 3-9, p. 57
List of groups • Autotrophs • Primary consumers • Secondary consumers • Tertiary (and higher) consumers • Omnivores • Decomposers • Detritivores
Range of Tolerance Higher limit of tolerance Lower limit of tolerance No organisms Few organisms Few organisms No organisms Abundance of organisms Population size Zone of intolerance Zone of physiological stress Zone of physiological stress Optimum range Zone of intolerance Low Temperature High Fig. 3-10, p. 58
Several Abiotic Factors Can Limit Population Growth • Limiting factor principle • Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance • Principle of sustainability connection: population control