People and the Earth's Ecosystem Module 1 PDF
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This document introduces the concept of ecology and how ecologists structure the study of the relationships between living organisms and their environment. It covers the different levels of organization within an ecosystem, including individuals, populations, communities, ecosystems, and biomes. The document also explores the biosphere and its components. It touches briefly on different types of ecosystems.
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People and the Earth’s Ecosystem ‘-logy,’ which comes from Latin and means ‘the Module 1 study of.’ Thus, ‘ecology’ translates to ‘the study of The Earth’s Ecosystem one’s home.’...
People and the Earth’s Ecosystem ‘-logy,’ which comes from Latin and means ‘the Module 1 study of.’ Thus, ‘ecology’ translates to ‘the study of The Earth’s Ecosystem one’s home.’ In this context, ecology focuses on the interactions Introduction between living organisms (biotic factors) and their How does modern living affect how people physical environment (abiotic factors), including perceive the natural environment and its elements such as temperature, soil, water, and biodiversity? other forms of matter and energy. The concept of ecology was first developed by the German - Currently, a significant portion of the human biologist Ernst Haeckel in 1869. population resides in urban areas. Urbanization and technological advancements have How Ecologists Structure an Organism and its diminished the direct interaction individuals Environment have with natural landscapes. While technology and media have enhanced Any ecosystem is structured according to the awareness of environmental issues by following tier structure: providing immediate access to information, modern living often erodes a deep sense of connection and appreciation for nature. Instant communication can raise consciousness about climate change, pollution, and conservation, yet consumerism and the pursuit of convenience frequently overshadow these environmental concerns. The focus on immediate gratification can shift attention away from long-term Individual – An individual is a unit member of a environmental impacts. species. Organisms are said to be members of the Modern living spaces replace natural environments same species if two individuals of the appropriate with fragmented or artificial settings, such as parks, sex are able to produce viable offspring. gardens, and zoos. This aspect of contemporary Population – A population is a group of society can alter people's perceptions of the individuals of the same species living together in a environment, leading them to view nature as particular area. something to be managed or controlled rather than as a wild and intrinsic part of life. Community – A community is a collection of populations of different species of plants and How can individuals contribute to environmental animals interacting with each other and living protection when modern living fosters artificiality together in an area. and apathy? Ecosystem – An ecosystem is an integration of - Growing movements are encouraging people to communities and also includes the energy flow in reconnect with nature through activities such as and out of the ecosystem. eco-tourism, outdoor recreation, and sustainable living practices. These efforts aim Biome – A biome is a large geographical area to restore and enhance the appreciation of characterized by specific climate conditions, plant natural environments. communities, and animal species. Biomes are typically classified based on factors such as Our future depends on our understanding of the temperature, precipitation, and the types of relationship between organisms and their organisms that live there. Common examples of environment. A lack of understanding alters our biomes include deserts, forests, grasslands, environment and leads to consequences that tundra, and aquatic environments (like oceans and threaten our existence. The growing concern about freshwater systems). the state of our environment has highlighted the importance of ecology as a crucial field in biology. Biosphere – The biosphere is the collective living The study of the Earth’s ecosystems falls under the component of the global ecosystem. The biosphere field of ecology. The term 'ecology' derives from the is supported by the atmosphere (the air), the Greek word ‘oikos,’ meaning ‘home,’ and the suffix hydrosphere (the bodies of water), and the geosphere (rocks and soils). Functions of an Ecosystem Nutrient Cycling in an Ecosystem 1. Regulatory function – ecosystems regulate Water Cycle the essential ecological processes of that Hydrologic cycle is a path of water through supports life systems and renders stability, it our ecosystem. Most of the water is stored in the is responsible for the cycling of nutrients ocean. The heat coming from the sun is the driving between biotic and abiotic components force for this cycle. The energy from the sun by providing us clean air and water. evaporates water. Water condenses and 2. Habitat function – ecosystems provide precipitates in the form of rain, snow or fog. Plants habitat to wild plants and animals and thus also emit water in the form of transpiration. conserve biological and genetic diversity. It 1. Evaporation: It is a process where water at the supports different food chains and food surface turns into water vapors. Water absorbs webs. heat energy from the sun and turns into vapors. 3. Production function – production of a wide 2. Condensation: Particles come close together range of goods ranging from food to raw and form clouds and fogs in the sky. materials. 3. Sublimation: Process where ice directly 4. Informational function – ecosystems converts into water vapors without converting into provide an essential 'reference function' and liquid water. contribute to the maintenance of human 4. Precipitation: The clouds (condensed water health by providing opportunities for spiritual vapors) then pour down as precipitation due to enrichment, cognitive development, wind or temperature change. recreation and aesthetic experience. Hail Rain Components of an Ecosystem Snow Biotic components – are the living components of 5. Transpiration: Liquid water is turned into water an ecosystem which includes both plants and vapor by the plants. animals, fungi, protists, and monerans. 6. Runoff: Water runs over the surface of earth. 7. Infiltration: The water seeps down and Autotrophs (producers) increases the level of the ground water table. ○ Can make their own food, photosynthesis in plants. Carbon Cycle Heterotrophs (consumer) Carbon molecule account 0.03% the ○ Primary Consumer (herbivores) atmosphere is gaseous form as carbon dioxide ○ Secondary Consumer (omnivores) (CO2), it is a structural component of organic ○ Tertiary Consumer (carnivores) molecules. The carbon cycle begins with the intake ○ Quaternary or Apex Consumer of carbon dioxide by photosynthetic organism plus Decomposers oxygen and hydrogen in water. Carbon dioxide is ○ Break down remains of plants and also released during respiration. animals. Abiotic components – are the nonliving In the ocean carbon is in the form of components of an ecosystem which includes many carbonate and bicarbonate used to build shells and factors such as temperature, sunlight, precipitation, skeletons of marine organisms. We accelerate the altitude, climate, salinity, acidity, etc. movement of carbon when we use fossil fuel. Since the industrial revolution the concentration of CO2 Pathways of Energy has increased significantly. From the Sun, energy generally flows into an 1. Photosynthesis ecosystem as diagrammed below: Photosynthesis: H20+ CO2→C6H12O6+ O2 Sun → Producers → Primary Consumers → 2. Combustion Secondary Consumers → Tertiary Consumers → Decomposers 3. Respiration 4. Sedimentation 5. Exchange 6. Extraction Nitrogen Cycle biome distribution on land. There are two types of biomes: Terrestrial and Aquatic Biomes. Nitrogen molecules make up 78% of the atmosphere. It is essential component of proteins, Terrestrial Ecosystem enzyme, DNA and organic compounds. Nitrogen enrichment came from a variety of sources: 1. Forest combustion of fossil fuel, agricultural fertilizers, a. Tropical Rain Forest occur in areas where the land clearing, forest burning, industry and animal temperature is high throughout the year and waste. precipitation occurs almost daily. It is the most 1. Nitrogen Fixation: Gaseous diverse biome in the world. Many staple foods are nitrogen is converted to ammonia by found in the tropics such as corn, banana and nitrogen fixing bacteria N2 (Gaseous sugarcane, even prescription drugs like nitrogen)-> NH3 (ammonia) erythromycin is derived from tropical fungi. 2. Nitrification: a process of converting ammonia b. Boreal Forest or Taiga these forests are to nitrates accomplished by Nitrosomonas and confined from Scandinavia, through European Nitrococcus bacteria Russia, across Siberia, to central Alaska and NH3 (ammonia)-> NO2(Nitrites)→ NO3(nitrates) across central Canada. They are dominated by evergreen conifers belonging to Picea (spruce and 3. Assimilation: Plants roots absorb ammonia and abies(fir) Animals consists of caribou, wolves, Nitrites -> Plant black bears and moose. 4. Ammonification: involve the conversion of c. Temperate Deciduous Forest is a forest found biological nitrogen to ammonia by between tropical and boreal forest. Sequoias of ammonifying bacteria Western North America and Eucalyptus trees of Biological Nitrogen-> decomposition-> NH3 southern Australia and found in this biome. In Asia (ammonia) temperate forest are found in Japan, China, Korea 5. Denitrification and eastern Siberia. NO3 (nitrates)→ nitrogen Gas-> atmosphere 2. Grassland Phosphorus Cycle a. Tropical Grassland or savanna mainly Phosphorus is essential to the energetics, composed of wide stretches of grass and trees like genetics and structure of living organisms. It forms Acacia which are fire-adapted and have extensive part of the ATP, RNA, DNA and phospholipid underground systems. It contains large numbers of molecules. Large quantities of phosphorus are hoofed animals such as giraffes, zebras and lions. found in marine deposit, marine sediments and b. Temperate Grassland is also known as sedimentary rocks. However, sedimentary rocks steppes or prairies, they are highly suited for are mined for fertilizer for agricultural purposes. agriculture, they are also known as the Phosphorus is released through weathering of breadbaskets of the world providing crops like corn rocks. As phosphorus is released, it is absorbed by and wheat. plants and some are washed in oceans. 3. Tundra 1. Weathering Tundra is also considered as an “arctic desert”, it 2. Absorption by Plants is known for its permafrost. They have a large 3. Absorption by Animals number of organisms that were able to adapt to survive the cold. It is composed of mosses, lichens, 4. Return to the Environment through grasses and dwarf trees, while animal communities Decomposition are made up of arctic foxes, snowy owls and TYPES OF ECOSYSTEMS hawks. There are no reptiles, amphibians The earth’s surface is a series of connected and insect like mosquitoes. ecosystems which is connected to a larger area 4. Desert called biomes. Biomes are a general type of communities with similar climate conditions, growth Desert biomes are very dry areas found in patterns and vegetation types. Temperature and temperate and tropical areas. Composed mainly of precipitation are the most important determinants in cacti, yuccas and Joshua trees. Animals tend to be small. Aquatic Ecosystem o Mistletoe and tree o Fleas and Dogs 1. Marine ecosystem o Plasmodium and Humans Marine ecosystem is made up majority of the 3. Commensalism – is a type of relationship in ocean the Atlantic, Pacific, Indian, Arctic and which one organism benefit without causing Antarctic which comprise approximately 70% of the harm to the other partner. Below are some earth’s surface. The largest and deepest ocean examples of commensal relations. basin is the Pacific. Oceans can be into vertical o Barnacles and Whales and horizontal zones. Each zone supports a o Remora fish and Sharks distinctive assemblage of marine life. o Cattle Egrets and Cattle o Orchids and Trees 2. The Freshwater Ecosystem includes rivers, o Pseudoscorpion and Beetle lakes and streams. 4. Amensalism – is an association between Freshwater wetlands, marshes and estuaries organisms of two different species in which one is inhibited or destroyed and the other Freshwater wetlands, marshes and estuaries occur is unaffected. Below are some examples of at the transitions between freshwater and marine amensal relations. and terrestrial environment. o Penicillium mold and bacteria Rivers and Streams o Black Walnut tree and other trees They characterized to have unidirectional currents, o Cattle trampling grass plants and animals have adaptive mechanisms for o Algal blooms and Aquatic life attaching themselves in rocks to prevent them from o Pseudoscorpion and Beetle being swept away by the current. 5. Predation – is a biological interaction where one organism, the predator, kills and Lakes eats another organism, its prey. Below are They are much like small seas. Most are found in some examples of predator-prey regions, work over by tectonics, volcanism and relationships. glacial activity, the geological forces that produce o Lion and Zebra lake basins. o Sharks and Seals SYMBIOSIS o Orcas and Sharks o Mantis and Hornet Symbiosis refers to any form of intimate 6. Competition – is the interaction between relationship or association between members two or more organisms that uses a common of two or more different species. Symbiotic resource, which is in short supply. relations are classified as follows: Competition can take the form of 1. Mutualism – is a symbiotic relationship in intraspecific competition and interspecific which both species benefit from each other. competition. Intraspecific competition, Below are some examples of mutual competition with members of their own relationship between organisms. species. Interspecific o Bees and flowering plants competition, competition between individuals o Clownfish and sea anemones of two species that reduces the fitness of o Liches (fungi and an algae both. Competition may occur between native (cyanobacteria)) and invasive species. Below are some o Oxpeckers and large herbivores examples of competition among species. o Legumes and Rhizobia (bacteria) o Hippopotamus and Crocodiles 2. Parasitism – is a form of symbiotic fighting over water habitat relationship where a parasite benefits from a host. The host is adversely affected and may die from this parasitic interaction. Below are some examples of parasite-host relationships. o Ticks and mammals o Tapeworms and Humans MODULE 2 Deforestation - Cutting down forests to create farms or pastures, or for other reasons, causes SUSTAINABILITY - refers to the ability to maintain emissions, since trees, when they are cut, release or preserve resources at a steady rate without the carbon they have been storing. depleting or damaging them. Economical Sustainability - to nurture a robust EFFECTS OF CLIMATE CHANGE: and prosperous economy for the well-being of present and future generations. Hotter temperatures - As greenhouse gas concentrations rise, so does the global surface Social Sustainability - focuses on promoting temperature. equitable and inclusive communities that caters to Rising sea levels - Sea level rise is an increase in the well being of all individuals. the level of the world's oceans due to the effects of Environmental Sustainability - preservation and global warming. nurturing of the planet. Loss of biodiversity - Biodiversity loss refers to the decline or disappearance of biological diversity, ECOLOGICAL FOOTPRINT - measure of human understood as the variety of living things that impact on the environment. inhabit the planet. Soil erosion - is a gradual process that occurs Components: when the impact of water or wind detaches and - Built-up Land removes soil particles, causing the soil to - Carbon deteriorate. - Cropland - Fishing Grounds TYPES OF POLLUTION - Forest - Grazing Land Air pollution - Air pollution refers to the release of pollutants into the air. Biocapacity - productive capacity of ecosystems to generate resources and absorb waste within a Water pollution Water pollution is the specific area. contamination of water bodies such as rivers, Biocapacity Deficit - When ecological footprint lakes, oceans, and groundwater with harmful exceeds the biocapacity of a region, it indicates an substances that can adversely affect aquatic unsustainable situation. ecosystems, human health, and the environment. Greenhouse Effect - process that occurs when Land pollution - land pollution is the destruction gasses in earth’s atmosphere trap the sun’s heat. and contamination of the land through the direct Greenhouse gas - it absorbs infrared radiation and indirect actions of humans from the sun in the form of heat that circulates in the atmosphere and eventually is lost to space. CAUSES OF POLLUTION: CLIMATE CHANGE - long-term alternation of Industrial Activities temperature and typical weather patterns in place. Transportation Global warming - long-term increase in earth’s Improper Waste Disposal average surface temperature. Mining and Extraction Burning fossil fuels CAUSES OF CLIMATE CHANGE: Natural Causes Generating power - generating electricity and heat EFFECTS OF POLLUTION by burning fossil fuels causes a large chunk of global emissions. Respiratory disease Manufacturing goods - Manufacturing and Heart disease industry produce emissions, mostly from burning Cancer fossil fuels to produce energy for making things like Groundwater poisoning cement, iron, steel, electronics, plastics, clothes, Socio-economic impact on humans and other goods. ENVIRONMENTAL DEGRADATION - deterioration Fossil fuels extracted and burned of the natural environment through the depletion of Oil leaked and spilled resources, pollution, and loss of biodiversity. Land deforested and developed Soil eroded and degraded CAUSES OF ENVIRONMENTAL DEGRADATION: Minerals mined Waste and toxic byproducts of 1. Poverty - is a major contributor to environmental manufacturing degradation. People living in poverty often experience hunger and food insecurity, which leads Causes: to over-exploitation of natural resources 2. Deforestation - is the permanent destruction of 1. Overpopulation - The overall population in the forests in order to make the land available for other world is more than 700 crores and still there is a uses. It is one of the leading causes of consistent increase in the overall earth populace environmental degradation because it reduces and this has been a critical factor in accelerating biodiversity, disrupts the water cycle, and the depletion of resources all around the world. contributes to climate change. 2. Poor Farming Practices - in order to satisfy the 3. Climate change - is a major contributor to basic needs and wants of the people, a huge stress environmental degradation because it can cause is laid on the land resources due to the soil erosion, which is the process of wearing away over-reliance on food production for daily nutritional the land surface by the action of natural forces consumption. such as wind, water, and ice. 3. Overconsumption of Natural Resources - In 4. Soil Damage - Soil erosion can have serious the year 1760 we witnessed industrial revolution consequences for the environment, as it can lead resulting in large-scale mineral and oil exploration to a decrease in soil fertility, an increase in and the practice has been gradually growing and sedimentation in waterways, and an increase in the leading to more and more depletion of various risk of flooding. natural resources and minerals 4. Environmental Pollution - The value of natural EFFECTS OF ENVIRONMENTAL DEGRATION: environment like soil, air, lakes and seas are being contaminated with sewage, radioactive and toxic Impact on human health: Human health is chemicals resulting in huge pollution. Unrestrained significantly harmed by environmental discharge of carbon monoxide, nitrousoxide and degradation. sulfur dioxide have resulted in the degradation of Atmospheric changes: The water cycle the ozone layer and global warming. and regular animal and plant activities are only a few of the naturally occurring EFFECTS OF RESOURCE DEPLETION processes that might be altered by environmental degradation. 1. Scarcity of Drinking Water - Another enormous Scarcity of natural resources: A lack of consequence of natural resource depletion is the resources, such as arable land, water, scarcity of drinking water. As the water pollution genetic resources, medicinal plants, and rate increases, there will not be a pure source of food crops, can be brought about by drinking water. environmental deterioration. 2. Oil and Mineral Depletio - one of the natural Global warming causes weather changes, resource available for human use is oil and it is a resulting in floods or droughts, which can nonrenewable resource that accounts for cause people to become displaced from approximately 40 percent of the total energy used their communities. globally. 3. Instability in the ecosystem - Further, the RESOURCE DEPLETION result of natural resource depletion is instability in the ecosystem. Due to deforestation, forest Resource depletion is the consumption of a ecosystem loss occurs; This causes instability in resource faster than it can be replenished. More food chains and food waves, and thus species people on the planet leads to more: fragmentation, extinction like issues arise. 4. Climate change - is the change in the local Sewerage and stock effluent weather over decades, which hampers our daily Fertilisers, herbicides and pesticides life. The global temperature has increased by 2º than it ever existed. So this is the most significant consequence of natural resource depletion. SOLUTION TO ENVIRONMENTAL PROBLEMS Transition to Renewable Energy Reforestation and Afforestation Sustainable Agriculture International Cooperation ENVIRONMENTALLY SUSTAINABLE SOCIETY Sustainable Environment - A sustainable environment is one where natural resources are utilized in a way that ensures they can replenish themselves over time. SUSTAINABLE WAY OF LIVING A sustainable way of living involves making conscious decisions to reduce one’s environmental footprint. Individual Actions Reduce consumption of non-renewable resources. Support local businesses. Advocate for better waste management practices (Jacimovic, n.d.). Business Responsibilities Define specific environmental goals. Minimize production waste. Transparently communicate sustainability efforts to their audience (Jacimovic, n.d.). HUMAN POPULATION AND URBANIZATION CAUSES FOR IMMIGRATION: - Urbanization is often driven by the search Population is defined as the totality of organisms for better jobs, better education, better of the same species observed in a specific healthcare, and better living conditions. geographical region at a particular time. ADVANTAGE: - According to Cambridge Dictionary, - can reduce poverty and inequality by population is the number of people living in a improving employment opportunities and particular country, area, or town. quality of life, including through better - Population is also used to refer to all the education and health. living things of a particular type or group DISADVANTAGE: who live in a particular area or environment. - can lead to congestion, higher crime rates, pollution, increased levels of inequality and THREE (3) FACTORS THAT ACCOUNT FOR social exclusion. RAPID INCREASE IN POPULATION: 1. The emergence of modern agriculture which POPULATION CHARACTERISTICS provides an increase in food production. Population size refers to the number of individuals 2. Technologies helped humans expand into all in a population. The study of the group areas of the planets and habitat. characteristics of a population, their changes over 3. Improved sanitation and development of time and prediction of future changes is known as antibiotics, vaccines in health care prolong the demography. lives of the people which decrease death rates. I. Population Density Population growth refers to the increase or The size of the population is represented by its decrease in the number of people in a given area fundamental property called density. It is generally over time. expressed as the number of individuals or the population biomass per unit area or volume. Factors Influencing Population Growth 1. Birth rate - higher birth rate leads to faster Types of Density population growth, while a lower birth rate slows it 1. Crude Density down. - Crude density is the density per unit of total 2. Death rate - higher death rate slows population space. growth or can even cause a population to decline, 2. Specific (or Ecological) Density while a lower death rate, especially combined with - Specific density is the density per unit of habitable a high birth rate, contributes to faster population space. growth. When deaths are fewer than births, the population increases. Determining Population Size 3. Migration - Movement of people from one Population size can be measured by several region to another. methods: - Emigration - When people move out of a region, 1. Abundance it decreases the population size. High emigration - Absolute number of individuals in the population. rates can lead to a population decline. 2. Numerical Density - Immigration - When people move into a region, it - Number of individuals per unit area or volume. It increases the population size. If immigration rates is expressed when the size of individuals in the are high, it can lead to a population increase. population is relatively uniform, as in mammals, insects and birds. Urbanization is the process by which large 3. Biomass Density numbers of people become permanently - Biomass density is expressed in terms of wet concentrated in relatively small areas, forming weight, dry weight, volume, and carbon and cities. nitrogen weight per unit area or volume. TWO (2) WAYS FOR A PLACE TO BE CALLED AN URBAN PLACE: Dp is the density of population, N is the total 1. High birth rate than death rate and; population as a number of people, and A is the 2. High immigration rate land area covered by that population. II. Natality increase can occur is referred to as saturation level or carrying capacity (death phase). In the last Natality refers to the rate of reproduction or birth phase the new organisms are almost equal to the per unit time. It is an expression of the production number of dying individuals (plateau or stationary of new individuals in the population by birth, phase) and thus there is no increase in population hatching, germination or fission. size. III. Mortality 2. J-Shaped Curve Mortality refers to the number of deaths for every - Here in the first phase there is no increase in 1,000 people per year population size because it needs some time for 1. Minimum or Specific or Potential adjustment in the new environment. Soon after the Mortality: population is established in the new environment, it - It represents the minimum theoretical starts multiplying rapidly. This increase in loss of individuals under ideal or population is continued till large amounts of food non-limiting conditions. Thus, even materials exist in the habitat. After some time, due under the best conditions individuals to increase in population size, food supply in the of a population would die of old age habitat becomes limited which ultimately results in determined by their physiological decrease in population size. This will result in a longevity. So it is constant for a J-shaped growth curve rather than S-shaped. population. 2. Ecological or Realized Mortality: - It refers to the death of individuals of a population under existing environmental conditions. Since it varies with environmental conditions, it is never constant. The maximum mortality occurs at the egg, larval, seedling and old age. Mortality is affected by a number of factors, such V. Age Distribution as, density, competition, disease, predation and environment. Death pre-reproductive (0-14), rates vary among the species and are reproductive (15-44) correlated with birth rates. post-reproductive (45 and older). IV. Population Growth VI. Population Fluctuations The growth is one of the dynamic features of This is called population fluctuation. There are species population. Population size increases in a three types of variations in the pattern of population characteristic way. When the number of individuals change: of population is plotted on the y-axis and the times on the x-axis, a curve is obtained that indicates the 1. Non-fluctuating: trend in the growth of population size in a given - When the population remains static over the time. This curve is called population growth curve. years, it is said to be non-fluctuating. 1. Sigmoid Curve (S-Curve) 2. Cyclic: - When a few organisms are introduced in an area, - The cyclic variations may be (a) seasonal, and (b) the population increase is very slow in the annual. Sometimes seasonal changes occur in the beginning (positive acceleration phase or lag population and there are additions to the population phase), in the middle phase, the population at the time of maximum reproduction and losses increase becomes very rapid (logarithmic phase) under adverse climatic conditions. and finally in the last phase population increase is slowed down (negative acceleration phase) until an 3. Irruptive equilibrium is attained and which the population - When the change in population density does not size fluctuates according to variability of occur at regular intervals or in response to any environment. The level beyond which no major obvious environmental factor, it is said to be irruptive fluctuation. In this there is a sudden of children and larger number of adults over the exponential or logarithmic increase in population age of 18. density in short time followed by equally quick drop in population density due to deaths, and final return 3. Zero population or decreasing populations to normal level or even below that level. When a country has an equal amount of birth and POPULATION'S AGE STRUCTURE death rates along with an equal amount of immigration and emigration rate, they are - It refers to the proportionate numbers of considered to be in a balanced population. people in different age categories in a given population for a defined time. 4. Negative Growth - It is closely related to the birth rate, death A decrease in birth rates and immigration rates rate and migration of a population. while experiencing an increase in elderly people Population Pyramid and emigration rates indicates the country is experiencing a negative growth rate. - Also called as age sex pyramid - a graphical illustration that shows the POPULATION CHANGES distribution of age groups of different Factors that Cause Populations to Change genders and ages in a population. - Density-dependent factors PARTS OF POPULATION PYRAMID - Density-independent factors - 3 AGE STAGES A number of factors affect a population's birth rate: - The vertical axis shows the age groups - The horizontal axis shows population size - Amount and quality of food available - Males(left) and female(right) - Age at first reproduction population size - Birth interval - Average number of young produced Types of Pyramid - Fecundity rates 1. Expansive Major Causes of Human Population Change - A population pyramid that is very wide at the a. Agricultural Revolution younger ages but narrow at the older ages, b. Industrial Revolution indicating a larger children population but a c. Progressing Growth smaller elderly population. POPULATION GROWTH REGULATION IN 2. Constrictive HUMAN - A constrictive pyramid is the opposite of an 1. Economic Development expansive pyramid, with a slight constriction in its younger age groups. - Studies on western European countries show that when countries become 3. Stationary industrialized and economically developed, - The top and bottom of the pyramid do not poverty decreases, their population tends to differ significantly in size and has a rather grow more slowly. smooth curve across all age groups 2. Family Planning Population Age Structure Diagrams - Family planning provides educational and 1. Rapid growth clinical services that help couples choose how many children to have and when to A country with a rapid growth has a population that have them. Such programs vary from culture is increasing at a very quick rate to culture, but most provide information on birth spacing, birth control, and health care 2. Slow growth: for pregnant women and infants A country experiencing slow growth usually indicates that the country will be a developed nation. The population will show a smaller number 3. Empowerment Women - Studies show that women tend to have fewer children if they are educated, hold a paying job outside the home, and live in societies where their human rights are not suppressed. Although women make up roughly half of the world's population, in most societies they do not have the same rights and educational and economic opportunities as men do. TRENDS IN THE WORLD 1. Fertility rate a. Total Fertility Rate (TFR) b. Age-Specific Fertility Rate 2. Mortality rate a. Crude Mortality Rate b. Age-Specific Mortality Rate c. Cause-Specific Mortality Rate d. Infant Mortality Rate 3. Aging population a. Declining Birth Rates b. Increasing Life Expectancy 4. Migration