Unit 2 – Life on Earth (Ecology) Part 1

1. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Human Population & the Environment • Why has human population grown so rapidly in the last 100 years? • expansion of agriculture and • industrial production and • lower death rates from improvements in hygiene and medicine. • In 2006, the population of developed countries grew exponentially at 0.1% per year. • Why do the populations in developed countries grow more slowly than in developing countries? • more educational opportunities for women leads to more women in the workforce and a delay in 1st childbearing • Increased awareness of birth control • Developing countries grew 15 times faster at 1.5% per year.

2. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1

3. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Population Age Structure • Used to make population & economic projections Populations with a large proportion of its people in the preproductive ages (1-14) have a large potential for rapid population growth. • What do each of these structures indicate?

4. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Exponential vs. logistic growth • No population can grow exponentially indefinitely. • Logistic Growth Curve • “S” shaped • Pop. Growth slows as it reaches carrying capacity • Logistic Carrying Capacity • Birth rates = Death rates • No net change in population

5. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Exponential vs. logistic growth • If a country has a CBR of 21 per 1000 and a CDR of 7 per 1000, the natural annual percent increase of its population is • .3% • 1.4% • 3% • 14% • 28% • 21/1000 – 7/1000 = 14/1000 = 1.4/100 = 1.4%

6. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 A declining population can cause problems as well: Which of these problems do you believe are the most important?

7. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Reproductive strategies • r-strategists (opportunists) Large number of smaller offspring with little parental care (populate quickly but little ability to compete at K). • K-strategists (competitors) Fewer, larger offspring with higher invested parental care (populate slowly but able to compete at K). • r (population growth). • K (carrying capacity)

8. Ch.4 Unit 2 – Life on Earth (Ecology) Part 1 Demographic transition As countries become economically developed, their birth and death rates tend to decline. Population Momentum when total fertility declines, there is a lag period before the rate of natural increase declines. This is due to all the people already at reproductive age 1. little population growth due to high infant mortality 2. death rates drops and birth rates remain high. 3. birth rate drops and approaches death rate.

9. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Biogeochemical Cycles • The complete path a chemical takes through the four major components – or reservoirs – of Earth’s systems • – or sinks –

10. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Biogeochemical Cycles Macronutrients Required by all life S P O N C H Required in small amounts by all life or in moderate amounts by some living things. Micronutrients Na K Ca Limiting Factors When elements are not available at the right times, in the right amounts and in the right concentrations relative to each other

11. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Geologic Cycle Tectonic Hydrologic Rock The processes responsible for formation and change of Earth materials

12. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Geologic Cycle Tectonic Hydrologic Rock • Divergent plate boundary: • Occurs at a spreading ocean ridge, where plates are moving away from one another • New lithosphere is produced (seafloor spreading) • Convergent plate boundary • Occurs when plates collide • Produces linear coastal mountain ranges or continental mountain ranges • Transform fault boundary • Occurs where one plate slides past another • San Andreas Fault in California

13. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Geologic Cycle Tectonic Hydrologic Rock Condensation Rain clouds Transpiration Evaporation Precipitation to land Transpiration from plants • Humans alter the water cycle by: • Withdrawing large amounts of freshwater. • Clearing vegetation and eroding soils. • Polluting surface and underground water. • Contributing to climate change. Precipitation Precipitation Evaporation from land Evaporation from ocean Surface runoff (rapid) Precipitation to ocean Runoff Surface runoff (rapid) Infiltration and Percolation Groundwater movement (slow) Ocean storage

14. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Ecosystem Cycles Sulfur – component of the amino acids methionine & cystein Water Sulfur trioxide H2SO4 Acidic fog and precipitation Sulfuric acid SO3 Ammonia Ammonium sulfate SO2 Oxygen (NH4)2SO4 H2S Hydrogen sulfide Sulfur dioxide Plants Volcano Dimethyl sulfide Industries (CH3)2S Animals Ocean Na2SO4 Sulfate salts Metallic sulfide deposits Decaying matter Sulfur Hydrogen sulfide H2S

15. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Carbon – base of all organic molecules • Humans alter the carbon cycle by adding excess CO2 to the atmosphere through: • Burning fossil fuels. • Clearing vegetation faster than it is replaced. Cellular respiration Cellular respiration Burning fossil fuels Photosynthesis Photosynthesis Diffusion Volcanoes Weathering/ Erosion Sedimentation

16. Gaseous nitrogen (N2) in atmosphere Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Global Chemical Cycles Nitrogen – required for DNA and all amino acids • Humans alter the nitrogen cycle by: • Adding gases that contribute to acid rain. • Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. • Contaminating ground water from nitrate ions in inorganic fertilizers. • Releasing nitrogen into the troposphere through deforestation. Nitrogen Food webs on land Nitrogen fixation Carbon Phosphorus Fertilizers Loss by denitrification Uptake by autotrophs Excretion, death, decomposition Uptake by autotrophs NO3 Ammonia, ammonium in soil Nitrogen-rich wastes, remains in soil Nitrate in soil NH4 NH3 Nitrification Ammonification NO2 Loss by leaching Loss by leaching Nitrite in soil Nitrification

17. Ch.5 Unit 2 – Life on Earth (Ecology) Part 1 Phosphorus – used in the structure of ATP • Humans alter the nitrogen cycle by:Humans • Removing large amounts of phosphate from the earth to make fertilizer. • Reducing phosphorous in tropical soils by clearing forests. • Adding excess phosphates to aquatic systems from runoff of animal wastes and fertilizers. mining Fertilizer excretion Guano agriculture weathering uptake by autotrophs uptake by autotrophs leaching, runoff Dissolved in Soil Water, Lakes, Rivers Land Food Webs Marine Food Webs Dissolved in Ocean Water death, decomposition death, decomposition weathering sedimentation settling out uplifting over geologic time Rocks Marine Sediments

18. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 Ecosystem & Ecosystem Management What is an ecosystem? • All of the biotic & abiotic factors in an area capable of sustaining life Matter cyclesand energy flowsthrough an ecosystem An ecosystem changes over time (ecological succession)

19. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 Energy Flow in Ecosystems

20. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 X Food Web Keystone Species is one whose impact on its community or ecosystem is disproportionately large relative to its abundance X

21. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 processes by which the environment produces resources. Ecosystem Services These services are extensive and diverse … affecting the quality of our land, water, food, and health. * moderate weather extremes and their impacts * disperse seeds * mitigate drought and floods * protect people from the sun’s harmful ultraviolet rays * cycle and move nutrients * protect stream and river channels and coastal shores from erosion All life depends upon the goods & services that ecosystems provide. • These include: • Water filtration • Groundwater recharge • Storm-water control • Air purification • Nutrient recycling • Crop pollination • Soil enrichment * detoxify and decompose wastes * control agricultural pests * maintain biodiversity * generate and preserve soils and renew their fertility * contribute to climate stability * purify the air and water * regulate disease carrying organisms * pollinate crops and natural vegetation

22. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 Humans have profoundly impacted the environment in many ways. Describe human impact in the context of an ecosystem. Why would it be wise to make every attempt preserve each element of an ecosystem? (c) What is the underlying cause for this tremendous human impact? (i.) What demographic factors affect the underlying cause mentioned in c.

23. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 • Humans have profoundly impacted the environment in many ways. • Describe human impact in the context of an ecosystem. • Full Points: • altering biogeochemical cycles with 2-3 specific examples • removal of keystone species

24. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 • Humans have profoundly impacted the environment in many ways. • (b) Why would it be wise to make every attempt preserve each element of an ecosystem? • Full Points: • Discussion of keystone species with a specific example • Discussion of ecosystem services with 2-3 specific examples

25. Ch.6 Unit 2 – Life on Earth (Ecology) Part 1 • Humans have profoundly impacted the environment in many ways. • (c) What is the underlying cause for this tremendous human impact? • Full Points: • Exponential human population growth • (i.) What demographic factors affect the underlying • cause mentioned in c. • Full Points: • Discussion of Industrialization effect on Birth Rates, & Death rates