Lecture 4.4.pdf

Lecture 4.4 AY2024-2025 Ecology Concepts and Prin...

Lecture 4.4 AY2024-2025 Ecology Concepts and Principles Ecosystems, Ecosystem Processes And Services, Food Chain/Web, Trophic Systems, Flow Of Energy, Biogeochemical Cycles, Population Dynamics, Interactions And Relationships, Biodiversity, Biological Evolution, Ecological Succession, Population Dynamics, Carrying Capacity, Population Dynamics Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 1 104 Outline Human Population Size Population The human population is Dynamics of Population growing exponentially at a Carrying Capacity rapid rate Human population was about 7.9 billion as of 30 Sep 2021. Based on the current increase rate there will be 9.9 billion people by 2050. Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering © https://www.worldometers.info 105 106 Human Population Size Factors Influencing Human Population Size Three major factors account for the rapid rise of the human population Birth rate Humans have expanded into almost all the planet’s climate zones and number of live births per 1,000 people in a population in a given year habitats The emergence of early and modern agriculture allowed us to grow more Total Fertility Rate food for each unit of land area farmed the average number of children born to women in a population during their reproductive years Death rates dropped sharply because of improved sanitation and health women are having fewer babies, but the world’s population is still care growing Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 107 108 ESE150 - Environmental Science and Engineering 1 Lecture 4.4 AY2024-2025 Factors Influencing Human Population Size Factors Influencing Human Population Size Factors affecting birth and fertility rates Factors affecting birth and fertility rates The educational and employment opportunities available for The importance of children as a part of the labor force women The cost of raising and educating children The average age at marriage The availability of, or lack of, private and public pension systems The availability of legal abortions Urbanization The availability of reliable birth control methods Religious beliefs, traditions, and cultural norms Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 109 110 Factors Influencing Human Population Size Factors Influencing Human Population Size Death rate Two useful indicators of the overall health of people in a country or region: number of deaths per 1,000 people in a population in a given year life expectancy average number of years a person born in the year of the estimate can be expected People started living longer and fewer infants died because of: to live. poverty affects life expectancy increased food supplies and distribution safer water supplies better nutrition infant mortality rate medical advances the number of babies out of every 1,000 born who die before their first birthday. improved sanitation one of the best measures of a society’s quality of life Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 111 112 Factors Influencing Human Population Size Age Structure Migration is the movement of people into (immigration) and out of the numbers or percentages of males and females in young, middle, and (emigration) specific geographic areas. older age groups in a given population. Pre-reproductive (0–14): normally too young to have children. Reasons for migration may include: Reproductive (15–44): normally able to have children. Employment Post-reproductive (45+): normally too old to have children. Political oppression and wars Religious persecution and ethnic conflicts can be used to make population and economic projections Certain types of environmental degradation Environmental refugees - people who migrate due to environmental degradation such as soil erosion and water and food shortages Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 113 114 ESE150 - Environmental Science and Engineering 2 Lecture 4.4 AY2024-2025 Age Structure Age Structure Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 115 116 Slowing Human Population Growth Slowing Human Population Growth The three most effective ways to slow or stop population growth are: promote economic development As countries become industrialized elevate the status of women and economically developed encourage family planning and reproductive health care. poverty declines per capita incomes rise populations tend to grow more slowly. Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 117 118 Slowing Human Population Growth Slowing Human Population Growth Women tend to have fewer children if they: Family planning are educated provides educational and clinical services that help hold a paying job outside the home couples choose how many children to have and when to have them have the ability to control their own fertility reduced the number of abortions and decreased the live in societies that do not suppress their rights numbers of mothers and fetuses dying during pregnancy Problems unplanned pregnancies resulting to abortion lack access to family planning services Prepared by: ACulala © https://www.facebook.com/chrisselromeaborja/ ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 119 120 ESE150 - Environmental Science and Engineering 3 Lecture 4.4 AY2024-2025 Slowing Human Population Growth Slowing Human Population Growth Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 121 122 Slowing Human Population Growth Environmental Resistance The resistance presented by the environmental conditions to limit a Responsible Parenthood and Reproductive Health Act of 2012 (RA species from growing out of control or to stop them from reproducing 10354) at maximum rate. to ensure the provision, delivery, and access to reproductive Abiotic Contributing Factors: health care services Unfavorable light to promote, protect, and fulfill women’s reproductive health and Unfavorable temperatures rights Unfavorable chemical environment - nutrients Biotic Contributing Factors: to include sex education in the school curriculum Low reproductive rate Specialized niche Inability to migrate or disperse Inadequate defense mechanisms Inability to cope with adverse conditions Prepared by: ACulala ESE150 - Environmental © JasrelleScience Serrano and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering © https://www.officialgazette.gov.ph/2013/03/18/implementing-rules-and-regulations-of-republic-act-no-10354/ 123 124 Carrying Capacity The maximum number of organisms a habitat can support over a given period of time due to environmental resistance The maximum population size of the species that the environment can sustain indefinitely Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 125 126 ESE150 - Environmental Science and Engineering 4 Lecture 4.4 AY2024-2025 Reproductive Strategies K Strategist Goal of every species is to produce as many offspring as possible Fewer, larger offspring Each individual has a limited amount of energy to put towards life and High parental care and protection of offspring reproduction Later reproductive age This leads to a trade-off of long life or high reproductive rate Most offspring survive to reproductive age Natural Selection has led to two strategies for species: Larger adults R - strategists Adapted to stable climate and environmental conditions K - strategists Lower population growth rate (r) Population size fairly stable and usually close to carrying capacity (K) High ability to compete Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 127 128 R Strategists References: Many small offspring https://www.biologyonline.com/dictionary/genetic-diversity Little or no parental care and protection of offspring https://byjus.com/neet/genetic-diversity/ Early reproductive age https://byjus.com/neet/why-is-species-diversity-important/ Most offspring die before reaching reproductive age https://www.scirp.org/ Small adults https://byjus.com/question-answer/what-is-ecological-diversity/ Adapted to unstable climate and environmental conditions https://growjungles.com/ecological-diversity-and-its-role-in-nature/ High population growth rate Environmental Science by G. Tyler Miller, Jr. Scott E. Spoolman Population size fluctuates wildly above and below carrying capacity Environmental Science: A Global Concern, Fourteenth Edition by William P. Low ability to compete Cunningham and Mary Ann Cunningham Environmental Engineering by KBK Prepared by: ACulala ESE150 - Environmental Science and Engineering Prepared by: ACulala ESE150 - Environmental Science and Engineering 129 130 ESE150 - Environmental Science and Engineering 5