Yawan jama'a
 Yawan jama'a | |
|---|---|
| Bayanai | |
| Ƙaramin ɓangare na |
number of individuals (en)  |
| Fuskar |
yawan jama'a da population genetics (en) |
Ƙaddamar da yawan jama'a ko rashin jin daɗi na alƙaluma shine halin ɗanyen haihuwa ya ƙaru a sakamakon yawan yawan haihuwa da ya wuce, ko da bayan yawan haihuwa ya faɗi, ko akasin haka. Wannan na faruwa ne saboda karuwar yawan haihuwa a halin yanzu yana haifar da karuwa a yawan mata masu shekaru kusan ashirin da arba'in bayan haka, ma'ana alkaluman karuwar yawan jama'a suna komawa baya sosai a kan yawan haihuwa. Sanannun misalan sun haɗa da Echo Boom (ƙara yawan adadin haihuwa yayin da jarirai suka kai shekarun renon yara) da ƙaruwar yawan jama'ar Sinawa a duk tsawon lokacin da aka tsara tsarin haihuwa ɗaya (daga 1979 zuwa 2021).
Ƙarfin yawan jama'a ya bayyana dalilin da yasa yawan jama'a zai ci gaba da karuwa ko da yawan haihuwa ya ragu ko ya ci gaba da raguwa ko da yawan haihuwa ya girma. Karuwar yawan jama'a na faruwa ne saboda ba wai adadin yara da kowacce mace ke tabbatar da karuwar yawan jama'a ba, har ma da yawan matan da suka kai shekarun haihuwa. A ƙarshe, lokacin da yawan haihuwa ya kai adadin maye gurbin kuma girman yawan mata a cikin sashin shekarun haihuwa ya daidaita, yawan jama'a yana samun daidaito kuma ƙarfin yawan jama'a ya zo ƙarshe. An bayyana ƙarfin yawan jama'a azaman rabon girman yawan jama'a a sabon matakin ma'auni zuwa girman yawan mutanen farko..[1]
Misali
[gyara sashe | gyara masomin]Ka ɗauka cewa yawan jama'a yana da ƙarni uku: Na farko (mafi tsufa), na biyu (haihuwar yara), da na uku (yara). Bugu da ƙari ɗauka cewa wannan yawan yana da yawan haihuwa daidai da huɗu (4). Wato, kowane ƙarni ya ninka girman na baya sau biyu. Idan an saita yawan jama'ar ƙarni na farko a 100, na biyu shine 200, kuma na uku shine 400. Shafin da ke ƙasa yana nuna yawan jama'a na farko a jere na farko.
| Lokaci | Farawa 1 | Farawa 2 | Farawa 3 | Farawa 4 | Farawa 5 | Yawan jama'a | Yawan haihuwa na yanzu |
|---|---|---|---|---|---|---|---|
| 0 | 100 (tsohon) | 200 (mai amfani) | 400 (yara) | 700 | 4 | ||
| 1 | ya mutu | 200 (tsofaffi) | 400 (mai amfani) | 400 (yara) | 1000 | 2 | |
| 2 | ya mutu | ya mutu | 400 (tsohon) | 400 (mai amfani) | 400 (yara) | 1200 | 2 |
Na farko a lura cewa tsara na biyu da na uku na mutanen farko sun ninka girman na baya. Jimlar yawan mutanen farko shine 700 = 100 + 200 + 400.
Sannan a ɗauka cewa a ƙarshen ƙarni na uku, haihuwa ta faɗi don maye gurbin (don sauƙi ɗauka cewa ya zama biyu). Yanzu kai yawan jama'a gaba zuwa tsara na gaba, layi biyu na maƙunsar bayanai. Ƙarni na farko ya mutu, kuma sabon ƙarni, na huɗu, daidai yake da na uku (saboda yanzu haihuwa ta maye gurbin). Maimaita tsarin don isa ƙarni na biyar (layi na 3 a cikin maƙunsar rubutu). Ƙarni na biyar kuma ya kasance daidai da na huɗu kuma yanzu tsararraki uku na yawan jama'a sun daidaita, kuma yawan jama'a ya kai ma'auni.
Yawan mutanen farko ya karu daga 700 zuwa 1,200 duk da cewa haihuwa ta ragu daga hudu zuwa maye (biyu) a karshen tsara na uku. Ƙarfin yawan jama'a ya ɗauki yawan jama'a zuwa matsayi mafi girma a cikin tsararraki biyu masu zuwa.
A lokacin da kasar Sin ta fara gabatar da manufar haihuwar yara daya, karuwar yawan jama'a ta ci gaba ba tare da la'akari da hakan ba. Ko da yake adadin yaran da aka haifa ya ragu sosai, yawan adadin matasan da suka balaga yana da mahimmanci. A shekarar 1979 da aka fara aiki da manufar haihuwar yara daya, yawan mutanen da suka zama manya ya dogara ne kan adadin haihuwa a shekarun 1950, ba a shekarar 1979 ba. Sakamakon haka, yawan jama'ar kasar Sin ya ci gaba da habaka yadda ake samun karuwar shekaru 20 da suka gabata. Yawan jama'ar kasar Sin ya ragu a karon farko a shekarar 2023.[2]
Ƙarin matakai zuwa ƙaruwar yawan jama'a
[gyara sashe | gyara masomin]Yawan jama'a yana tasiri ga yawan haihuwa da mutuwar nan take a cikin yawan jama'a wanda ke ƙayyade yawan ci gaban halitta. Koyaya, don yawan jama'a su sami cikakkiyar ƙarancin ci gaban halitta, abubuwa uku dole ne su faru.
1. Yawan haifuwa dole ne ya daidaita zuwa adadin maye gurbin (ya kamata yawan haihuwar ya zama 1). Idan yawan haihuwa ya kasance mafi girma fiye da yawan maye gurbin, yawan jama'a zai ci gaba da girma.
2. Dole ne Yawan mace-mace ya daina raguwa, wato, dole ne ya kasance daidai.
3. A ƙarshe, tsarin shekaru dole ne ya daidaita da sabon yawan haihuwa da mutuwa. Wannan mataki na ƙarshe yana ɗaukar mafi tsawo don kammalawa.[3]
Sakamakon
[gyara sashe | gyara masomin]Yawan jama'a yana da tasiri ga manufofin yawan jama'a saboda dalilai da yawa.
1. Dangane da kasashe masu yawan haihuwa (misali a cikin kasashe masu tasowa), ingantaccen yanayin yawan jama'a, ma'ana cewa yawan jama'a yana karuwa, ya bayyana cewa wadannan kasashe za su ci gaba da bunkasa duk da raguwar yawan haihuwa da sauri.
2. Game da ƙasashe masu ƙarancin haihuwa (misali a Turai), ƙarancin yawan jama'a yana nuna cewa waɗannan ƙasashe na iya fuskantar raguwar yawan jama'a ko da sun yi ƙoƙarin haɓaka ƙimar haihuwa zuwa canjin canji na 2.1. Misali, wasu kasashen gabashin Turai suna nuna raguwar yawan jama'a ko da adadin haihuwarsu ya farfado zuwa matakin maye gurbinsu. Ƙarfin yawan jama'a na iya zama mara kyau idan yawan haihuwa yana ƙarƙashin matakin maye gurbin na dogon lokaci.
3. Ƙaddamar da yawan jama'a ya nuna cewa maye gurbin matakin haihuwa ra'ayi ne na dogon lokaci maimakon nuni na yawan ci gaban yawan jama'a na yanzu. Dangane da tsarin shekarun da suka wuce, yawan haihuwa na yara biyu kowace mace na iya yin daidai da girma ko raguwa na ɗan lokaci..[4]
Ƙididdiga
[gyara sashe | gyara masomin]
Don ƙididdige ƙarfin yawan jama'a ga yawan jama'a A, an gina ƙididdiga na yawan jama'a wanda adadin haihuwar yawan jama'a A nan da nan ya zama matakin maye gurbin. A karkashin irin wannan yanayi, yawan jama'a za su daidaita su zama jama'a na tsaye, ba tare da canje-canje na shekara zuwa shekara ba a cikin ƙayyadaddun adadin shekaru ko jimlar yawan jama'a. Ana ƙididdige ƙarfin yawan jama'a ta hanyar raba wannan jimillar adadin jama'a na ƙarshe da farkon yawan jama'a. Momentum, Ω, ana iya bayyana shi kamar:
A cikin wannan daidaitattun, b shine yawan haihuwa yayin da e<sub id="mwdQ">o shine tsawon rayuwa a lokacin haihuwa. Q shine jimlar yawan haihuwa ta hanyar haihuwa ta farko.
Ana amfani da wannan daidaitattun do samun Q (dukkanin haihuwa ta hanyar haihuwa ta farko), r shine yawan ci gaba kuma μ shine yawan jama'a da ba su canza ba a lokacin haihuwa. Ro shine Net Reproduction Rate na yawan mutanen da ba sa canzawa.[5]
Yawan jama'a yana faruwa ne sakamakon sauyin canjin alƙaluma na ƙasar. Lokacin da yawan mace-mace ya ragu, matasa suna tsira da ƙuruciya kuma yawan tsufa suna rayuwa tsawon rai. Yawan haihuwa ya kasance babba, yana haifar da girman yawan jama'a gabaɗaya. Dangane da yunƙurin yawan jama'a, ko da an maye gurbin yawan haifuwa nan da nan tare da maye gurbin matakan haihuwa, yawan jama'a zai ci gaba da haɓaka saboda yawan waɗanda suka riga sun haihu da ke shiga shekarun haihuwa..[1]
Dubi kuma
[gyara sashe | gyara masomin]- Demography - Kimiyya da ke hulɗa da yawan jama'a da tsarin su, ta hanyar kididdiga da ka'ida
- Human overpopulation - Yanayin da aka gabatar inda yawan mutane ya wuce karfin muhalli
- List of population concern organizations
- Population stabilization - Yawan jama'a ba ya ƙaruwa ko raguwaShafuka da ke nuna taƙaitaccen bayanin manufofi
- ↑ 1.0 1.1 Blue, Laura; Espenshade, Thomas J. (2011). "Population Momentum Across the Demographic Transition". Population and Development Review. 37 (4): 721–747. doi:10.1111/j.1728-4457.2011.00454.x. ISSN 0098-7921. PMC 3345894. PMID 22319771.
- ↑ Master, Farah; Master, Farah (17 January 2024). "China's population drops for second year, with record low birth rate". Reuters.
- ↑ Bongaarts, John (2009). "Human population growth and the demographic transition". Philosophical Transactions of the Royal Society B: Biological Sciences. 364 (1532): 2985–2990. doi:10.1098/rstb.2009.0137. ISSN 0962-8436. PMC 2781829. PMID 19770150.
- ↑ "The impact of population momentum on future population growth" (PDF). United Nations Dept of Economic and Social Affairs, Population Division. October 2017.
- ↑ Kim, Young J.; Schoen, Robert (1997-08-01). "Population momentum expresses population aging". Demography (in Turanci). 34 (3): 421–427. doi:10.2307/3038294. ISSN 0070-3370. JSTOR 3038294. PMID 9275250.