Population Dynamics · 人口动态
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| crude birth rate/kruːd bɜːθ reɪt/ | 粗出生率 | cū chū shēng lǜ |
| crude death rate/kruːd deθ reɪt/ | 粗死亡率 | cū sǐ wáng lǜ |
| rate of natural increase/reɪt ɒv ˈnætʃərəl ˈɪŋkriːs/ | 自然增长率 | zì rán zēng zhǎng lǜ |
| total fertility rate/ˈtəʊtl fɜːˈtɪlɪti reɪt/ | 总和生育率 | zǒng hé shēng yù lǜ |
| replacement level/rɪˈpleɪsmənt ˈlevl/ | 更替水平 | gēng tì shuǐ píng |
| doubling time/ˈdʌblɪŋ taɪm/ | 倍增时间 | bèi zēng shí jiān |
How populations change
- A population changes through births, deaths, and migration.
- Rates are measured per 1,000 people per year.
- Crude birth rate 粗出生率 (CBR) and crude death rate 粗死亡率 (CDR) are the basics.
人口如何变化
- 人口通过出生、死亡和迁移而变化。
- 各种比率以每 1,000 人每年衡量。
- 粗出生率(CBR)和粗死亡率(CDR)是最基本的。
Natural increase
- The rate of natural increase 自然增长率 (RNI) = (CBR - CDR) ÷ 10, as a percent.
- It ignores migration — only births minus deaths.
- A positive RNI means the population is growing from within.
自然增长
- 自然增长率(RNI)=(CBR - CDR)÷ 10,以百分比表示。
- 它忽略迁移——只看出生减死亡。
- RNI 为正意味着人口从内部增长。
CBR = 28 and CDR = 8 per 1,000. What is the rate of natural increase, as a percent? · 粗出生率 CBR = 28，粗死亡率 CDR = 8（每 1,000 人）。自然增长率是多少（百分比）？
RNI = (28 - 8) ÷ 10 = 2.0%. · RNI = (28 - 8) ÷ 10 = 2.0%。
The rate of natural increase includes migration. · 自然增长率包括移民。
RNI is births minus deaths only — it ignores migration. · RNI仅计算出生减去死亡——它忽略了移民。
Fertility and doubling
- The total fertility rate 总和生育率 (TFR) is the average children per woman.
- About 2.1 is replacement level 更替水平 — enough to keep a population steady.
- Doubling time 倍增时间 ≈ 70 ÷ RNI% (the "rule of 70").
生育率与倍增
- 总和生育率(TFR)是每名妇女平均生育的孩子数。
- 大约 2.1 是更替水平(replacement level)——足以维持人口稳定。
- 倍增时间(doubling time)≈ 70 ÷ RNI%(“70 法则”)。
Which population measure? · 哪种人口指标？
Match each description to the right population measure. · 将每个描述与正确的人口指标匹配。
If a country's RNI is 2%, roughly how many years until its population doubles (rule of 70)? · 如果某国的自然增长率(RNI)为2%，根据“70法则”，其人口大约需要多少年才能翻倍？
Doubling time ≈ 70 ÷ 2 = 35 years. · 翻倍时间 ≈ 70 ÷ 2 = 35年。
The total fertility rate that keeps a population steady (replacement level) is about... · 保持人口稳定的总生育率(更替水平)大约是……
About 2.1 children per woman replaces the parents (allowing for child mortality). · 每位女性约生 2.1 个孩子可替代父母（考虑儿童死亡率）。
Match each measure to its meaning. · 将每个指标与其含义匹配。
CBR = births/1,000; RNI = natural growth %; TFR = children per woman. · CBR = 每1,000人出生数；RNI = 自然增长百分比；TFR = 每位女性的子女数。
RNI ignores migration, so it is not the same as total population change. A country with RNI of 0 can still grow (from immigration) or shrink (from emigration). Do not treat natural increase as the whole story.
RNI 忽略迁移,所以它不等于总人口变化。一个 RNI 为 0 的国家仍可能增长(因移入)或萎缩(因移出)。不要把自然增长当作全部。
A country has CBR = 30 and CDR = 10 (per 1,000). Its RNI = (30 - 10) ÷ 10 = 2%. Its doubling time ≈ 70 ÷ 2 = 35 years — the population will double in about a generation.
一个国家 CBR = 30、CDR = 10(每 1,000 人)。它的 RNI =(30 - 10)÷ 10 = 2%。它的倍增时间 ≈ 70 ÷ 2 = 35 年——人口将在大约一代人的时间内翻倍。
CBR and CDR are births/deaths per 1,000/year. RNI = (CBR - CDR) ÷ 10 (%), ignoring migration. TFR is children per woman (2.1 = replacement). Doubling time ≈ 70 ÷ RNI%.
CBR 和 CDR 是每 1,000 人每年的出生/死亡数。RNI =(CBR - CDR)÷ 10(%),忽略迁移。TFR 是每名妇女的孩子数(2.1 = 更替)。倍增时间 ≈ 70 ÷ RNI%。