A. Origin of life
B. Biological evolution
C. Classification of humans
D. Evolution of hominids
E. Evolution of humans
II. Global ecology and human interferences
A. Nature of ecosystems
B. Energy flow
C. Global Biogeochemical cycles
III. Human Population, planetary resources and conservation
A. Human population growth
B. Human use of resources and pollution
C. Biodiversity
D. Working toward a sustainable society
DISCLAIMER: The opening paragraph of chapter 22 sums up a world view that does not coincide with my personal beliefs BASED ON AS MUCH SCIENTIFIC EVIDENCE AS THE THEORY PRESENTED IN CHAPTER 22. It poses the question, "Could a chemical evolution have produced the first cell(s) on the primitive earth. My answer to this question is: If it could, it hasn't been proven to. Let's recall the experiment that Carl Sagan hailed in his classic series, "Cosmos." He explained Stanley Miller's experiment that simulated the earth's early atmosphere. There were amino acids produced by these experiments, but an organic protein that led to biological synthesis was never produced. Even the means of amino acid synthesis is questionable as it was managed and produced thanks to the INTELLIGENCE of the scientist(s) behind the experiment. Later the experiments were deemed fairly irrelevant as the idea of what the atmosphere was made of changed. There has not yet been a proven piece of evidence that the events leading to life, believed by most scientists, is accurate or reliable, or FACTUAL. That is the first stumbling block to overcome before even moving on to the more advanced evolution proposed by chapter 22. If those are overcome than we can move on to more advanced hurdles that stand defiantly in the way of the simply-stated theory behind the writing within. Much less we start this chapter after the beginning of the earth...and thus our solar system...and thus the universe. The odds of the beginning of each one of these is beyond improbable, astronomically at odds, and impossible (mathematically speaking). Therefore the review herein is stressed to be nothing more than an unproven theory that does not agree with my own...or the empirical and evidential scientific process. We must admit that the origin of the universe...or earth...or its inhabitants cannot be empirically evident, as it already happened. Therefore it is up to us as REASONING beings to decide which theory is the most logical for the origin of the universe. I am confident in saying that I do not believe that the theory of Neo-Darwinian Evolution is the most logical.
A. Origin of life
The fundamental principle of biology states that all living things are made of cells. Every cell comes from a preexisting cell. Therefore the very first living thing must have come from non-living chemicals. The theory presented herein would simply state that there was a slow increase in the complexity of chemicals that would produce the first cells on the earth.
The sun and the planets are believed to have been formed over a 10-billion-year period. At 4.6 billion years ago the solar system was formed and in place. The earth's gravitational field is strong enough to have an atmosphere. With less mass there would be no atmosphere. IF MORE THAN CONDITIONS WOULD BE MUCH MORE LIKE THAT OF PLANETS LIKE VENUS...unlivable. Possibly, the early earth's atmosphere was formed by gases escaping from volcanoes. If that was the case the early atmosphere would have been made of: H2O, N2 and CO2, with small amounts of H2 and CO. This would have been a very hot atmosphere and water would have been in gas form, creating dense clouds. As the earth cooled the water became liquid. The oceans could have been formed by millions of years of heavy rainfall.
Small organic compounds might have been formed through the concentration of organic compounds and much available energy. Stanley Miller's experiment (spoke
of in DISCLAIMER) produced organic compounds by synthesizing an environment similar to that thought of to be the early earth's atmosphere.RNA is thought to be the first basic macromolecule thought to carry out replication and continuation of organic synthesis, before DNA, the more stable protein complex, became dominant. This would have been some 3.5 billion years ago. The Protein-first hypothesis states that since amino acids join together when exposed to dry heat, perhaps they formed in puddles or something similar. When they returned to water they formed polypeptides which would aid in the forming cells.
Sidney Fox, who proposed the above stated hypothesis, also hypothesizes that lipid introduction to microspheres would have produced a lipid-protein that could carry on metabolism, but could reproduce. This cell would have been a fermenter since there was not free oxygen.
The supporters of these two different hypotheses about how DNA and, therefore, true cells could come about.
How the earth may have looked very
early on.
If cells evolved, the first cells would have been prokaryotic. These are cells without nuclei. From them would have come eukaryotes, then multicellular organisms and onward. Biological evolution is the process through which species change. Descent from the first cells could explain why all organisms have similar chemical makeup. Adaptations are the biological changes that help an organism survive. Charles Darwin formed the theory of evolution while spending time in the tropics. He concluded that lifeforms are so varied from place to place because of evolutionary adaptation. Fossils could be the best evidence for evolution. Paleontologists look to the stratum to determine or hypothesize the age of a creature. Transitional fossils would be those with characteristics of two different groups. One defended example is the archaeopteryx, which is a bird with reptile-like features. Because of the distribution of vegetation in various climates, scientists conclude that it also adapted to its environment. The similarity of bones in animals is another also used as evidence for evolution. Most proponents of evolution believe that natural selection was a very important factor in why we have the species we have today. Natural selection refers to the survival of organisms best suited to their environmen
t.C. Classification of humans
Through classification we can determine which organisms are most alike. Organisms of the same domain have general characteristics alike. Those in the same genus have much more specific characteristics in common. DNA data is being used more and more to trace the ancestry of species. Humans are primates, mammals that have binocular vision, grasping hands, larger brains and lower reproductive rates. They have mobile and opposable limbs and digits. There are many similarities between the skeleton of humans and of chimpanzees. However important differences are why human walk upright and chimpanzees do not.
Human belong to the moderately general
class of mammals.
According to the evolutionary tree all primates evolved from a common ancestor. According to it there was a common ancestor for monkeys apes and hominids 45 MYA (million years ago.) There was one for all apes about 15 MYA. Then one for African apes 7MYA. The split between
the ape and human lineage is thought to have occurred at that time. Humans couldn't have evolved from apes because they are contemporaries, but would have shared a common ancestor. Biologists do not agree on what the first hominid would be. Hominid features include the bipedal posture, larger brains and flat faces. Some of the fossil pieces thought to be related to hominids are those of the species Sahelanthropus tchadensis, Orrorin tugenesis and Ardipithecus kadabba.Human, Darren Naish, at the family reunion
with artists' renditions of what some hominids
may have looked like.
E. Evolution of humanswith artists' renditions of what some hominids
may have looked like.
Fossils are called "Homo" if the brain size is 600cm or larger, jaws and teeth resemble humans and tool use is evident. Homo habilis would be the first, dated between 2 and 1.9 MYA. They would have probably been omnivores. Since bones at their campsites have cut marks, they had tools. They probably used very crude rocks to do the work. Society and culture would have begun here if there was a cooperation between hunting and gathering. Speech and knowledge transmission were vital to this process. Homo erectus would have followed between 1.9 and .3 MYA. H. erectus would have had a larger brain and a flatter face.
Most scientists believe in the "Out-of-Africa" theory of human evolution: that homo sapiens evolved in Africa from homo erectus and then migrated. Neandertals are thought to be the another branch in the evolutionary chain. They would have had a larger brain than the modern human and would have been far more heavily muscled. Cro-Magnon DNA is supposed to be
very different from Neandertals to the point that there was no interbreeding. They may have lived side by side. They would have been such advanced hunters that they may have been responsible for the extinction of many large animals.Humans are widely distributed and have many different anatomic features. Some believe that some of these differences may be adaptations to their environment. Others cannot be explained. All humans are extremely similar.
Though there are variations
all humans are very similar.
II. Global Ecology and Human Interferences
A. Nature of ecosystems
The Biosphere is every where on earth where organisms are found. It is really one giant ecosystem, however there are divisions of ecosystems based on temperature and rainfall, for terrestrial ecosystems, or biomes. Some are: tropical rain forest, tropical grassland, temperate forest of grassland, taiga, desert and tundra. There are two types of aquatic ecosystems, saltwater and freshwater. The freshwater ecosystems are standing water and running water.
Biotic components of an ecosystem are the living organisms. Autotrophs are organisms that produce their own food from inorganic nutrients and outside
energy. These are most plants and algae. Heterotrophs need a source of organic nutrients. Some are herbivores, that only feed on plants or algae. Some are carnivores, that is meat eaters. Some are both; these are called omnivores. Other still are detritus feeders, which means they feed on the decomposing part of organic matter. Some of these are called decomposers because their feeding breaks down and releases nutrients for plant use. A niche is an organisms role in an ecosystem. Its interaction is part of the whole of the ecosystem. Every ecosystem is characterized by two factors, energy flow and chemical cycling. Nutrients absorbed or made by producers is passed on to consumers (heterotrophs). Then it is absorbed by decomposers who will return them to the soil or atmosphere where they will again be absorbed by the producers.
The Rain forest is the wettest of
all terrestrial ecosystems.
B. Energy flow
A food web is a diagram that describes the feeding relationships (trophic) of organisms in an ecosystem. They give us a picture of the energy flow. A graz
ing food web describes that which begins with producers and ends with the top carnivores. A detrital food web shows that which starts with detritus and moves to decomposers and on up to the top carnivores. If a diagram shows a single path of energy flow it is called a food chain. A trophic level contains all the organisms that feed at a single link in the food chain. Only about 10% of the energy of one trophic level is available to the next level. That is why an ecosystem can only support so many carnivores. Because of the loss of energy at each level it can be described as an ecological pyramid. It can also be described this way due to the amount of organisms and their weight, or biomass, at each level.
A food web of an temperate forest
ecosystem.
C. Global biogeochemical cycles
All organisms require various organic and/or inorganic nutrients. These chemicals circulate through biotic and geological components. This can either be done in a gaseous or a sedimentary (taken from soil by producers and passed on) cycle. Some different components of cycling are reservoirs or exchange pools. Human activities upset the normal balance by removing chemicals from reservoirs and exchange pools.
The hydrologic cycle, or water cycle, works like this: Evaporation occurs. Once in the atmosphere the water vapor condenses and falls as precipitation. Runoff makes water flow into lakes, streams, wetlands and the ocean. Other water percolates into the soil and some goes deep down into aquifers, which return in springs or wells.
Humans interfere by: withdrawing water from aquifers, clearing vegetation and building which prevents percolation, and pollute water and add sewage and chemicals.
The carbon cycle works in this way: Producers take carbon dioxide from the air and through photosynthesis. They turn it into valuable nutrients which are consumed by auto and heterotrophs. When organisms respire carbon is returned to the atmosphere as carbon dioxide and then is cycled back to plants. Dead and living organisms are reservoirs for carbon. Some of these are fossil fuels from plant and animal remains that have been converted over time.
Human interference has caused more CO2 to be deposited in the atmosphere than released. There is practically twice as much CO2 being released as there already has been in the atmosphere. The release of certain gases like NO and CH4 as well as CO2 has caused a change in climate that may make the earth's temperature rise, among other things. It is often called by its archaic name: global warming. Now it is mostly referred to as climate change, because much more is happening than a rise in temperature.
Nitrogen makes up about 78% of the atmosphere. Plants do not utilize N2 and it can limit the amount of growth in an ecosystem. It does, however use ammonium. N2 is converted to ammonium by some bacteria and it is used by the host plants of these bacteria. Plants also use nitrates, NO3, Nitrates are made when high energy occurrences make them bind with oxygen. Soil bacteria can also convert NH4 (ammonium) into No2, nitrite, which is converted by other bacteria into nitrate. During assimilation plants turn the nitrate into proteins and nucleic acids. Dentrification is the return of nitrate to N2 which counterbalances nitrogen fixation. Human activities double the fixation rate. The runoff enters lakes and rivers where overgrowth occurs. When the overgrowth dies off the decomposers will boom which ends in a large fish kill. The burning of fossil fuels has put too much nitrogen oxides and sulfur dioxide into the air. They attach to water vapor and
come down in rainfall. The acidic rain lowers crop yields and eats the marble, metal and stonework. These gases also combine with sunlight to make smog which doesn't allow the proper escape of pollutants out of the atmosphere.
Phosphorus is released through geological upheaval and through the slow weathering of rocks. It is used by plants to make ATP, phospholipids and nucleotides for DNA and RNA. Consumers get it from producers. Through decay phosphates are once again available to producers. Its scarcity controls the size of populations.
Humans boost the supply of phosphate through mining. This also causes overgrowth in waterways. The pollutants produced are very dangerous because they are not easily degraded and become more and more concentrated as they pass through the food chain. The oceans are most greatly affected by all the pollutions, where many species of fish are on the brink of extinction.
A. Nature of ecosystems
The Biosphere is every where on earth where organisms are found. It is really one giant ecosystem, however there are divisions of ecosystems based on temperature and rainfall, for terrestrial ecosystems, or biomes. Some are: tropical rain forest, tropical grassland, temperate forest of grassland, taiga, desert and tundra. There are two types of aquatic ecosystems, saltwater and freshwater. The freshwater ecosystems are standing water and running water.
Biotic components of an ecosystem are the living organisms. Autotrophs are organisms that produce their own food from inorganic nutrients and outside
energy. These are most plants and algae. Heterotrophs need a source of organic nutrients. Some are herbivores, that only feed on plants or algae. Some are carnivores, that is meat eaters. Some are both; these are called omnivores. Other still are detritus feeders, which means they feed on the decomposing part of organic matter. Some of these are called decomposers because their feeding breaks down and releases nutrients for plant use. A niche is an organisms role in an ecosystem. Its interaction is part of the whole of the ecosystem. Every ecosystem is characterized by two factors, energy flow and chemical cycling. Nutrients absorbed or made by producers is passed on to consumers (heterotrophs). Then it is absorbed by decomposers who will return them to the soil or atmosphere where they will again be absorbed by the producers.The Rain forest is the wettest of
all terrestrial ecosystems.
B. Energy flow
A food web is a diagram that describes the feeding relationships (trophic) of organisms in an ecosystem. They give us a picture of the energy flow. A graz
ing food web describes that which begins with producers and ends with the top carnivores. A detrital food web shows that which starts with detritus and moves to decomposers and on up to the top carnivores. If a diagram shows a single path of energy flow it is called a food chain. A trophic level contains all the organisms that feed at a single link in the food chain. Only about 10% of the energy of one trophic level is available to the next level. That is why an ecosystem can only support so many carnivores. Because of the loss of energy at each level it can be described as an ecological pyramid. It can also be described this way due to the amount of organisms and their weight, or biomass, at each level.A food web of an temperate forest
ecosystem.
All organisms require various organic and/or inorganic nutrients. These chemicals circulate through biotic and geological components. This can either be done in a gaseous or a sedimentary (taken from soil by producers and passed on) cycle. Some different components of cycling are reservoirs or exchange pools. Human activities upset the normal balance by removing chemicals from reservoirs and exchange pools.
The hydrologic cycle, or water cycle, works like this: Evaporation occurs. Once in the atmosphere the water vapor condenses and falls as precipitation. Runoff makes water flow into lakes, streams, wetlands and the ocean. Other water percolates into the soil and some goes deep down into aquifers, which return in springs or wells.
Humans interfere by: withdrawing water from aquifers, clearing vegetation and building which prevents percolation, and pollute water and add sewage and chemicals.
The carbon cycle works in this way: Producers take carbon dioxide from the air and through photosynthesis. They turn it into valuable nutrients which are consumed by auto and heterotrophs. When organisms respire carbon is returned to the atmosphere as carbon dioxide and then is cycled back to plants. Dead and living organisms are reservoirs for carbon. Some of these are fossil fuels from plant and animal remains that have been converted over time.
Human interference has caused more CO2 to be deposited in the atmosphere than released. There is practically twice as much CO2 being released as there already has been in the atmosphere. The release of certain gases like NO and CH4 as well as CO2 has caused a change in climate that may make the earth's temperature rise, among other things. It is often called by its archaic name: global warming. Now it is mostly referred to as climate change, because much more is happening than a rise in temperature.
Nitrogen makes up about 78% of the atmosphere. Plants do not utilize N2 and it can limit the amount of growth in an ecosystem. It does, however use ammonium. N2 is converted to ammonium by some bacteria and it is used by the host plants of these bacteria. Plants also use nitrates, NO3, Nitrates are made when high energy occurrences make them bind with oxygen. Soil bacteria can also convert NH4 (ammonium) into No2, nitrite, which is converted by other bacteria into nitrate. During assimilation plants turn the nitrate into proteins and nucleic acids. Dentrification is the return of nitrate to N2 which counterbalances nitrogen fixation. Human activities double the fixation rate. The runoff enters lakes and rivers where overgrowth occurs. When the overgrowth dies off the decomposers will boom which ends in a large fish kill. The burning of fossil fuels has put too much nitrogen oxides and sulfur dioxide into the air. They attach to water vapor and
come down in rainfall. The acidic rain lowers crop yields and eats the marble, metal and stonework. These gases also combine with sunlight to make smog which doesn't allow the proper escape of pollutants out of the atmosphere.Phosphorus is released through geological upheaval and through the slow weathering of rocks. It is used by plants to make ATP, phospholipids and nucleotides for DNA and RNA. Consumers get it from producers. Through decay phosphates are once again available to producers. Its scarcity controls the size of populations.
Humans boost the supply of phosphate through mining. This also causes overgrowth in waterways. The pollutants produced are very dangerous because they are not easily degraded and become more and more concentrated as they pass through the food chain. The oceans are most greatly affected by all the pollutions, where many species of fish are on the brink of extinction.
Acid deposition has killed these trees.
III. Human Population, Planetary Resources and Conservation
A. Human population growth
Since about 1750 the growth rate of the the human population has increased steadily. Then around the 1930's the population spiked in the less-developed countries (LDCs.)This is very different than the population growth in more-developed countries (MDCs) where growth is modest and people enjoy a good living standard. In LDCs most people live in poverty.
Between 1850 and 1950 the MDCs doubled their populations, thanks to modern medicine and new public health standards. Then there was a decline in birth rates around 1950 so population increase has been slowed. The MDCs have a growth rate of about 0.1% as a whole. The U.S. however, has a growth rate of about 0.6%. This partly due to constant migration to the U.S. from other countries. There is no leveling off to the
U.S. population growth. In the LDCs death rates decreased drastically after World War II, thanks to modern medicine. The birth rate remained high. Between 1960 and 1965 the growth rate was about 2.5%, the height of growth rate. The collective rate is about 1.6% now. Between 2002 and 2050 the population of the LDCs is expected to go up to about 8 billion. Some of this will happen in Africa, but most will be in Asia, because so many in Africa are dying of AIDS. Asia has been and will experience water loss, loss of biodiversity and urban pollution. Because more women are reaching reproductive years, than women leaving them, the population is increasing in the LDCs.
Resources are any biotic or abiotic substance that helps meet needs. Nonrenewable resources are limited. They include land, fossil fuels and minerals. These sources will run out. Renewable resources are naturally replenished. However some of these, such as animals, have population thresholds, below which they are unrecoverable. Pollution is a side effect of some resource consumption. It is an negative alteration of the environment. The amount of pollution put out is proportional to the size of the population. On an average there 83 persons living per square mile on the planet, including all the uninhabitable parts of the world!About 40% of the population lives near a coastline. In the US more than half the population live near the coast. This leads to beach erosion, which decreases marine population and decreases the buffer zone for storms. The loss of wetlands, for example, contributed to the devastation caused by Hurricane Katrina. Forty percent of the earth's land is desert. Desertification is the conversion of semiarid land to desert. It usually begins through the overgrazing of animals on semiarid land. Estimations say that 75% of all rangeland is in danger of desertification. Rain forest land is also subject to desertification when it is deforested. The soil is not suitable for long-term farming, because the nutrients are all in the current vegetation. When it is removed the soil loses its fertility quickly.
Though clean drinking water should be the right of all people, most freshwater utilized by industry and agriculture. Seventy percent of all freshwater is used to irrigate crops. The freshwater demand is due in large to these activities. In MDCs more water is used for bathing, cooking, flushing toilets and watering lawns than drinking. Damming has caused extensive flow loss on most major rivers of the world. Sometimes the amount of water lost to evaporation and seepage from dams is equal to the amount made available. An absurd amount of water has been used out of aquifers, supply that has been there for possibly thousands of years. The High Plains Aquifer has been depleted of over half of its water supply. Subsidence, settling of the soil, occurs as a result. This causes sinkholes. By 2025 2/3 of the world's population may be living in areas with serious water shortage. Some solutions may help. Planting drought-resistant and saltwater-resistant crops. Using drip irrigation saves about 50% more water than sprinkler methods. Farmers have little incentive to switch, though. Adopting new conservation plans could help industries cut water demands by more than half!
Food supply generally comes from three activities: growing crops, raising animals and fishing the seas. Modern farming methods have increased food production but have had damaging effects. Some of these are pollution from fertilizers, cancer-causing agents and loss of soil fertility from pesticides, water loss, pollution and loss of fuel sources. Some helpful practices minimize harm. Intercropping can cause the use of less fertilizers. Contour farming preserves top soil and water. Because livestock feed on most of the crops produced, at least in the US, the consumption of less meat and more vegetables will greatly reduced the poor farming practices and fuel consumption of both industries.
Sources of energy are integral to modern society. Some are renewable and some are not. Environmental degradation occurs due to use of nonrenewable energy sources. About 75% of the world's energy comes from fossil fuels. Nuclear power is also nonrenewable and its effects are dangerous. Persons in the MDCs use as much energy in one day as persons in LDCs do in one year! Most of this is fossil fuels, of course. Climate change and the "greenhouse effect" have been caused due to the burning of fossil fuels and clearing of forests. Some effects could be: the major rise of the oceans, loss of wetlands, danger to coastal cities and loss of coral reefs. Renewable energy sources include: hydropower (if used correctly can produce plenty of energy without detrimental effects to the environment.), geothermal energy, wind power and solar energy.
Minerals are nonrenewable raw materials like fossil fuels, sand, gravel, phosphate and metals. Heavy metals are detrimental to human health and their hazrdous wastes must be discarded carefully. Strip mining for minerals makes the land devoid of vegetation and washes harmful substances into water supplies. The most common contaminates made by mining and other industrial products are heavey metals and synthetic organic chemicals.
C. Biodiversity
Biodiversity is the variety of life through numbers of different species. Biodiversity is in great crisis as there are staggering predictions of extinction of species. Habitat loss is a major player in loss of biodiversity.Human occupation and deforesting are causing habitat loss especially in the tropical rain forests and coral reefs. Alien species, those introduced into new ecosystems, often drive out the native species. Pollution causes: acid deposition, climate change, ozone depletion and directly kills animals when wastes put synthetic organic chemicals directly into the food supply. Overexploitation, that is the over extraction of species to a devastating reduction, is threatening extinction of species of plants and animals. Disease from domestic animal encroachment is fatal to local wildlife. Some extinctions may occur simply to disease.
Biodiversity is very important to the environment and to the population. Many plants are important for medicinal reasons. There are an estimated 328 types of drugs yet to be discovered in plants of the tropical rain forests. Bacterium play roles in cure and also in research of their damaging effects. Animals that carry them are important to researchers. Wild crops are still important because they contain different genetic makeup that may be important to virus resistance or have natural pesticides. Natural predators and pest control are preferable to chemical pesticides. Flowering plants need certain birds, bats and insects to pollinate them. Some forested areas are more valuable for the trees' o
utput (fruit, wax) than their timber. The one is a renewable source, the other is not. It is more economical to save ecosystems rather than individual species. Disposing of waste, properly, is one method. Using partially treated wastewater lets soil bacteria ensure a complete cleansing of wastes. Using wetlands to breakdown pollutants is also efficient. There is no substitute for freshwater. It is absolutely necessary. Using it effectively through forest and wetland protection will ensure its availability. Soil erosion is curable simply by keeping the ecosystem intact. Trees and plants will regulate climate when allowed.
Urban sprawl endangers the local wildlife.
D. Working toward a sustainable society
Sustainable societies could always provide the same amount of goods and services for future generations. The MDCs excessive consumption as well as the population growth of the LDCs stresses the environment. Wasteful practices are causing great harm to the environment. Urban sprawl is causing loss of habitat. More natural practices can help us reach a sustainable society. Nature gives us clues. It uses only solar energy as its renewable source. Cycles ensure the return of materials to use. Following these cues and preserving the natural ecosystems is integral to a sustainable society. Certain practices must be done in areas from agriculture to enterprise. Efficient cars, that are light and gas thrifty, are one change we could make to approve efficiency of transportation and sustainability. Both city and country need to be sustainable because they depend on each other for goods and services. In rural areas the emphasis should be on preservation as much as possible. Preserving native grasses and planting trees is integral to the preservation of top soil. Some measures that can be taken are:
using cover crops between cash crops, multiuse farming, composting and organic gardening, using drip irrigation and retention ponds, increasing the planting of cultivars, using precision farming, using natural pest control, planting a variety of species, planting multipurpose trees, maintaining and restoring wetlands, using renewable forms of energy and support local farmers, fisherman and feed stores
Some possible ways to help make cities sustainable are:
using energy efficient transportation, solar and geothermal energy sources for heat and seawater air-conditioning, Using green roofs, or wild gardens on the tops of buildings for temperature control/food/runoff, Use sediments, artificial wetlands and holding ponds for storm-water, plant native species to attract natural wildlife and use less water, create greenbelts using walking and biking paths, revitalize old sections before building new ones, use efficient lighting fixtures and promote sustainability through recycling business equipment and using low-maintenance building materials.
A combination green roof and park.
With better assessment of funds with consideration of well-being and environmental impact we may better plan for the future and direct energies where they would be best used.
III. Human Population, Planetary Resources and Conservation
A. Human population growth
Since about 1750 the growth rate of the the human population has increased steadily. Then around the 1930's the population spiked in the less-developed countries (LDCs.)This is very different than the population growth in more-developed countries (MDCs) where growth is modest and people enjoy a good living standard. In LDCs most people live in poverty.
Between 1850 and 1950 the MDCs doubled their populations, thanks to modern medicine and new public health standards. Then there was a decline in birth rates around 1950 so population increase has been slowed. The MDCs have a growth rate of about 0.1% as a whole. The U.S. however, has a growth rate of about 0.6%. This partly due to constant migration to the U.S. from other countries. There is no leveling off to the
U.S. population growth. In the LDCs death rates decreased drastically after World War II, thanks to modern medicine. The birth rate remained high. Between 1960 and 1965 the growth rate was about 2.5%, the height of growth rate. The collective rate is about 1.6% now. Between 2002 and 2050 the population of the LDCs is expected to go up to about 8 billion. Some of this will happen in Africa, but most will be in Asia, because so many in Africa are dying of AIDS. Asia has been and will experience water loss, loss of biodiversity and urban pollution. Because more women are reaching reproductive years, than women leaving them, the population is increasing in the LDCs.Because of the high birth rate in countries like
Burma, the country has a young population
that will continue to grow.
B. Human Use of Resources and PollutionBurma, the country has a young population
that will continue to grow.
Resources are any biotic or abiotic substance that helps meet needs. Nonrenewable resources are limited. They include land, fossil fuels and minerals. These sources will run out. Renewable resources are naturally replenished. However some of these, such as animals, have population thresholds, below which they are unrecoverable. Pollution is a side effect of some resource consumption. It is an negative alteration of the environment. The amount of pollution put out is proportional to the size of the population. On an average there 83 persons living per square mile on the planet, including all the uninhabitable parts of the world!About 40% of the population lives near a coastline. In the US more than half the population live near the coast. This leads to beach erosion, which decreases marine population and decreases the buffer zone for storms. The loss of wetlands, for example, contributed to the devastation caused by Hurricane Katrina. Forty percent of the earth's land is desert. Desertification is the conversion of semiarid land to desert. It usually begins through the overgrazing of animals on semiarid land. Estimations say that 75% of all rangeland is in danger of desertification. Rain forest land is also subject to desertification when it is deforested. The soil is not suitable for long-term farming, because the nutrients are all in the current vegetation. When it is removed the soil loses its fertility quickly.
Though clean drinking water should be the right of all people, most freshwater utilized by industry and agriculture. Seventy percent of all freshwater is used to irrigate crops. The freshwater demand is due in large to these activities. In MDCs more water is used for bathing, cooking, flushing toilets and watering lawns than drinking. Damming has caused extensive flow loss on most major rivers of the world. Sometimes the amount of water lost to evaporation and seepage from dams is equal to the amount made available. An absurd amount of water has been used out of aquifers, supply that has been there for possibly thousands of years. The High Plains Aquifer has been depleted of over half of its water supply. Subsidence, settling of the soil, occurs as a result. This causes sinkholes. By 2025 2/3 of the world's population may be living in areas with serious water shortage. Some solutions may help. Planting drought-resistant and saltwater-resistant crops. Using drip irrigation saves about 50% more water than sprinkler methods. Farmers have little incentive to switch, though. Adopting new conservation plans could help industries cut water demands by more than half!
Food supply generally comes from three activities: growing crops, raising animals and fishing the seas. Modern farming methods have increased food production but have had damaging effects. Some of these are pollution from fertilizers, cancer-causing agents and loss of soil fertility from pesticides, water loss, pollution and loss of fuel sources. Some helpful practices minimize harm. Intercropping can cause the use of less fertilizers. Contour farming preserves top soil and water. Because livestock feed on most of the crops produced, at least in the US, the consumption of less meat and more vegetables will greatly reduced the poor farming practices and fuel consumption of both industries.
Sources of energy are integral to modern society. Some are renewable and some are not. Environmental degradation occurs due to use of nonrenewable energy sources. About 75% of the world's energy comes from fossil fuels. Nuclear power is also nonrenewable and its effects are dangerous. Persons in the MDCs use as much energy in one day as persons in LDCs do in one year! Most of this is fossil fuels, of course. Climate change and the "greenhouse effect" have been caused due to the burning of fossil fuels and clearing of forests. Some effects could be: the major rise of the oceans, loss of wetlands, danger to coastal cities and loss of coral reefs. Renewable energy sources include: hydropower (if used correctly can produce plenty of energy without detrimental effects to the environment.), geothermal energy, wind power and solar energy.
Minerals are nonrenewable raw materials like fossil fuels, sand, gravel, phosphate and metals. Heavy metals are detrimental to human health and their hazrdous wastes must be discarded carefully. Strip mining for minerals makes the land devoid of vegetation and washes harmful substances into water supplies. The most common contaminates made by mining and other industrial products are heavey metals and synthetic organic chemicals.
C. Biodiversity
Biodiversity is the variety of life through numbers of different species. Biodiversity is in great crisis as there are staggering predictions of extinction of species. Habitat loss is a major player in loss of biodiversity.Human occupation and deforesting are causing habitat loss especially in the tropical rain forests and coral reefs. Alien species, those introduced into new ecosystems, often drive out the native species. Pollution causes: acid deposition, climate change, ozone depletion and directly kills animals when wastes put synthetic organic chemicals directly into the food supply. Overexploitation, that is the over extraction of species to a devastating reduction, is threatening extinction of species of plants and animals. Disease from domestic animal encroachment is fatal to local wildlife. Some extinctions may occur simply to disease.
Biodiversity is very important to the environment and to the population. Many plants are important for medicinal reasons. There are an estimated 328 types of drugs yet to be discovered in plants of the tropical rain forests. Bacterium play roles in cure and also in research of their damaging effects. Animals that carry them are important to researchers. Wild crops are still important because they contain different genetic makeup that may be important to virus resistance or have natural pesticides. Natural predators and pest control are preferable to chemical pesticides. Flowering plants need certain birds, bats and insects to pollinate them. Some forested areas are more valuable for the trees' o
utput (fruit, wax) than their timber. The one is a renewable source, the other is not. It is more economical to save ecosystems rather than individual species. Disposing of waste, properly, is one method. Using partially treated wastewater lets soil bacteria ensure a complete cleansing of wastes. Using wetlands to breakdown pollutants is also efficient. There is no substitute for freshwater. It is absolutely necessary. Using it effectively through forest and wetland protection will ensure its availability. Soil erosion is curable simply by keeping the ecosystem intact. Trees and plants will regulate climate when allowed.Urban sprawl endangers the local wildlife.
Sustainable societies could always provide the same amount of goods and services for future generations. The MDCs excessive consumption as well as the population growth of the LDCs stresses the environment. Wasteful practices are causing great harm to the environment. Urban sprawl is causing loss of habitat. More natural practices can help us reach a sustainable society. Nature gives us clues. It uses only solar energy as its renewable source. Cycles ensure the return of materials to use. Following these cues and preserving the natural ecosystems is integral to a sustainable society. Certain practices must be done in areas from agriculture to enterprise. Efficient cars, that are light and gas thrifty, are one change we could make to approve efficiency of transportation and sustainability. Both city and country need to be sustainable because they depend on each other for goods and services. In rural areas the emphasis should be on preservation as much as possible. Preserving native grasses and planting trees is integral to the preservation of top soil. Some measures that can be taken are:
using cover crops between cash crops, multiuse farming, composting and organic gardening, using drip irrigation and retention ponds, increasing the planting of cultivars, using precision farming, using natural pest control, planting a variety of species, planting multipurpose trees, maintaining and restoring wetlands, using renewable forms of energy and support local farmers, fisherman and feed stores
Some possible ways to help make cities sustainable are:
using energy efficient transportation, solar and geothermal energy sources for heat and seawater air-conditioning, Using green roofs, or wild gardens on the tops of buildings for temperature control/food/runoff, Use sediments, artificial wetlands and holding ponds for storm-water, plant native species to attract natural wildlife and use less water, create greenbelts using walking and biking paths, revitalize old sections before building new ones, use efficient lighting fixtures and promote sustainability through recycling business equipment and using low-maintenance building materials.
A combination green roof and park.
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