Intro to Populations
Do r- or K-selected species produce more offspring typically?
r-selected species
What letters best represent exponential and logistic growth curves? (make sure to say which is which)
Exponential = J
Logistic = S
When we say crude birth rate or crude death rate, that means that it is out of ______ people.
1000
That is why we divide crude numbers by 10 to convert them to 100 (like when we need percentages)
What would you expect the trend of total fertility rate to be as you progress through the demographic transition model?
It would decrease.
What is the total replacement fertility number for developed countries?
What about developing countries?
(Provide the number to the tenths)
Developed: 2.1
Developing: 2.5 (higher infant mortality)
When people have 2 children, they are replacing the mother and father in the population.
The maximum reproductive rate of a population when resources are unlimited and environmental conditions are ideal is the __________ ____________.
Biotic potential!
Predator-prey interactions keep each other's populations in check which creates a ______ & ______ cycle.
Boom & bust
If the country of WilliamBlountTopia had a growth rate of 0.8%, how long would it take the population to double?
Rule of 70:
70/0.8 = 87.5 years
What stage of the demographic transition model would you most likely find child labor?
Stage 1 - Pre-Industrial
What are the top three countries with the highest populations? List them in order from greatest to least.
1. India
2. China
3. United States
1.What type of species are most susceptible to invasives: native K-selected species or native r-selected species?
2. Are invasive species typically r- or K-selected?
1. Native K-selected species
2. r-selected (like the rabbits that took over Australia!)
What type of organisms would experience a larger oscillation around their carrying capacity - r- or K-selected species?
r-selected species because their populations increase very quickly but also die off very quickly
If the country of WilliamBlountTopia had 75 births, 35 immigrants, 30 deaths, and 25 emigrants per 1000, what would the overall growth rate be for the country?
((75+35)-(30+25))/10 = growth rate
(110-55)/10
55/10
5.5%
Why does the CBR stay high during Stage 2 of the demographic transition model but fall in Stage 3? What are some major pieces of information that define those 2 stages?
Stage 2: Health care and sanitation begins to improve; better food and water
Stage 3: Education for women begins to increase; contraceptives become more common - both lead to the decrease in CBR
If you were calculating the Rule of 70 and a population had a negative growth rate, would you say that your result would be the population's doubling time or halving time?
It would be the population's halving time. (How many years it would take for the population to decrease by half if the negative growth rate stays the same.)
Explain the difference between a generalist and a specialist. Then, give an example of each.
Generalist: has a broad niche, wide range of tolerance, can handle unstable/changing conditions (ex: raccoon)
Specialist: has a narrow niche, narrow range of tolerance, prefers stable habitats (ex: panda)
What happens immediately after a population overshoot?
The population will decline because they have exceeded their carrying capacity.
If the country of WilliamBlountTopia had a CBR of 40 and a CDR of 19, what would the population growth rate be?
2.1%
40-19 = 21
21/10 = 2.1%
Draw 4 age structure diagrams.
1. Rapid growth
2. Slow growth
3. Stable
4. Declining
1. Rapid - triangle with very wide base and skinnier as you go up
2. Slow growth - normal triangle
3. Stable - more like a rectangle
4. Declining - pre-reproductive age is smaller than the other stages
If there are 27,000 births each year in the country of WilliamBlountTopia and the total population is 8,900,000, what is the CBR?
(27,000/8,900,000) x 1000 = CBR
0.003 x 1000 = 3
3 births per 1000 people per year
Draw the 3 survivorship curves.
Then, label each section as Type I, II, or III.
Also, include whether those species would be considered r- or K-selected.
Finally, give an example of an organism that would fit those Types.
Type I: most live to old age, take care of children, only a few children, K-selected, ex: elephants/humans
Type II: constant loss, some have lots of offspring and some have few - do care for them somewhat, K-selected, ex: squirrels/birds
Type III: most die early, lots of children, little to no parental care, r-selected, ex: sea turtles/fish/spiders
Explain the difference between density-dependent and density-independent limiting factors.
Then, provide one example of each.
Density-dependent: affects populations more as the size of the population increases (is dependent on the density); ex: disease, predators, space, food
Density-independent: affects populations no matter the size of the population (is independent of the density); ex: floods, droughts, forest fires
If the country of WilliamBlountTopia had a CDR of 14 and a population growth rate of 1.3%, what would the CBR be?
(CBR-CDR)/10 = population growth rate
(CBR-14)/10 = 1.3
CBR-14 = 1.3 x 10
CBR = 13 + 14
CBR = 27
Draw the first four stages of the demographic transition model & label the 3 factors seen on the chart. Also, label the names of the stages.
Stage 1 - Pre-Industrial: High CBR and CDR, low overall population
Stage 2 - Transitioning: High CBR, CDR drops rapidly, overall population increases rapidly
Stage 3 - Industrial: CBR is starting to fall, CDR falls slower, and overall population increases at a slower rate
Stage 4 - Post-Industrial: CBR continues to fall, CDR falls even slower, and overall population increases and starts to stabilize
WilliamBlountTopia had 1.9 x 10^7 births in the year 2025.
How many births is that?
19,000,000 births