IBESS Test 3: Populations and Whatnot

Aya >:( 11/29/22

J Curve

Exponential growth of a population shaped like a J on a graph. Only known species to have this growth is humans so far. N

Formula: Nt = N0e^rt
Nt=Future Pop - N0=Current Pope=base of natural log(2.72) - r=intrinsic growth rate - t=time

Why has the human population grown so much in the last 200 years?

We keep making new advancements in science that keep us from hitting that carrying capacity.

What information can you determine by examining this age structure pyramind? :
\ /
||
/ \

They had a lot of growth early on but dipped in the middle and are now taking curve up again.

How are Nigeria and Guatemala's population pyramids similar and how are they different?

Guatemala's growth rate has slowed down more and in Nigeria, you are more likely to live into your old age than in Guatemala. They both also have a low life expectancy.

What is population momentum and why is it important?

it is the lag that occurs between death rates and birth rates that takes a few generations to even out. It creates a booming phase in the middle. It also means that our population continues to grow even after the death rate falls below replacement rate.

How has the distribution of humans changed over the last 2 thousand years?

We started out in Africa and migrated pretty late to north America and south Africa. India, China, and Europe were really the most consistent places where lots of population resided through history.

Why are some areas set aside for the protection of biodiversity more successful than others?

Organizations and governments vary and the shape of the environment matters too. Finding funding + good management + cultural attitude + distance from other habitats

Why was the beaver population in yellowstone affected after the wolves were reintroduced?

The wolves ate the elk which had no predators with the absence of wolf which made the water bad and the soil bad which drove away trees from the shoreline which drove off beavers.

Why do species experience exponential growth and not logistical growth?

Species devoid of limiting factors will experience exponential growth until something becomes too big an obstacle for them to keep going.

Is the Kudzu vine a generalist or specialist species? Fly Traps? Longleaf Pine?

It is a generalist and invasive and can grow in many environments.
Fly Trap: Endemic - Specialist
Longleaf Pine: Endemic - Specialist

What considerations must be included when tagging different animal species?

It can't inhibit the animal's movements, how you acquire them matters(peaceful and natural), can't harm the animal more than what would be reasonable, and it can't make them too obvious to predator or prey

How would you estimate the unknown size of a population?

You would take samples and generalize to the greater population. We could also use the capture-mark-release-recapture

South Sudan, AKA Bakory Tageldin has the highest growth. What are strategies to contain this growth?

-family planning: contraception, birth control, access to safe abortions
-Improve the economics of the people on large and small scales
-Increase social programs for older people
-Furthering healthcare for pregnant women
-furthering womens' rights

Logistic Growth - The Most Realistic

Population decreases and hangs out around the carrying capacity when limiting factors come into play. The limiting factors combat the growth rate making a negative feedback loop.
S Curve

Carrying Capacity (k)

Max # of individuals that can be SUStainable supported by a given habitat and it can vary between different times of the year and from year to year.

Crude Birth Rate

number of births per 1000 individuals per year - Crude because it is true of the whole populations and it isn't age specific

Formula:
(Number of births)/(total pop.) * 1,000

Crude Death Rate

(number of deaths)/(total pop.) * 1,000

Natural Rate of Increase (r)

(crude birthrate-crude death rate)/10
Immigration and emigration are ignored in these calculations

Fertility

Potential for reproduction in a population

fertility rate

Number of births per 1000 females of child-bearing age per year

total fertility

Average number of offspring a female has in her entire lifetime

Fecundity

the maximum number of offspring an organism could have over its lifetime

Doubling Time

Years it would take for a population to double in size -> "the rule of 70"
DF = (70)/(r)

Life History Strategy for Species

1. there is a continuum of different reproductive strategies used by organisms

2. r-strategists = more offspring

3. k-strategists = less offspring

Type I Species

A species where most die at an old age

Type II Species

A species with an equal chance of dying at any stage in their life

Type III Species

A species that is most likely going to die younger

r-Strategists

-non-specific diets/habitats
-High biotic potential
-small offspring
-little-no parental care
-high young mortality rate
-short lifespan
-can live in extreme conditions
Ex. Grasses, insects, fishes

k-Strategists

-Specific diets/habitats
-low biotic potential (mature slowly)
-Relatively large offspring
-Extensive parental care
-High survival rate in young
-Long lifespan
-Late succession species
-Affected more by invasive species
Ex Mammals, climax species (your mother)

Density Dependent Factors

-Rate of growth is related to the density of organisms in a population
-A specific factor intensifies as a population increases
-Important Negative Feedback mechanisms lead to the stability of a population (competition, predation, waste accumulation, etc..)

Density Independent Factors

-Rate of population growth not related to density
-factors are not related to population size: weather, geological events

Malthusian Growth

The population grows exponentially but the food growth only grows linearly so at some point, an overshoot will happen, and a huge crash will ensue.
Malthus also thought that humans were too lazy and selfish to voluntarily reduce growth rates.

Paul Ehrlich

Population Bomb: Population Growth is the cause of the symptoms like poverty and social problems

Karl Marx

-Population Growth IS the symptom rather than a root cause of poverty and other social problems going on
-Argued real causes of these problems are exploitation and oppression.
-Equal distribution to everyone was a way of slowing population growth

Role of Technology

Technological optimist: there could be no carrying capacity for our species because there will always be technological advancements to help ourselves out.

Least Economically Developed Countries

80% of the pop. and 90% of the growth will be here from now on. The life expectancy is about 68 years old and these are typically young, poor, and rapidly growing countries

Most Economically developed Countries

All wealthy, older, and mostly shrinking countries have a fertility rate below the replacement level. Life expectancy in these countries is closer to 78 years.

Growth Rates

-Replacement level is 2.1 to make up for the parents and to make up for any mishappenings that could happen to that person
-LEDC's could have a replacement level anywhere from 2.2 to 3

Life Expectancy

Average age a newborn can be expected to gain in a given society

Life Span worldwide

-Declining Mortality leads the cause of growth
-Worldwide average lifespan went from 31 in 1900 to 72 in 2016

Demographic Transition Model

• Predicts how a country would develop as it has increased in technology

• Model based on past western trends so it might not represent everyone

5 Stages of the DTM

1: Pre-Industrial - isolated tribes and natives 2: Early Transitional 3: Late Transitional 4: Industrial 5: Post-Industrial

Factors that could affect birth and fertility rates (there are a lot so this is kind of a list)

-Average level of education and affluence
-importance of children as a labor force
-cost of raising children and educating children
-educational and employment opportunities for women
-average age of marriage
-availability of private and public pension
-availability of legal abortions
-availability of reliable methods of birth control
-religious beliefs, traditions, and cultural norms

Infant Mortality

Defined as the death of a baby before its first birthday. It is measures /1000. CDC top 5 causes of infant mortalty: 1 Birth Defects 2 Preterm Birth, low birth weight 3 Maternal pregnancy complications 4 sudden infant death syndrome 5 injuries like suffocation

Limits to human Population Growth

Human carrying capacity is determined by:
-rate of energy + material consumption
-Level of pollution
-the extent of human interference in the global life support system

Impact of Human Pop. on the Environment

Influence = Pop * Affluence * Technology

What are the problems with establishing carrying capacity for Humans

-Range of resources is greater than any other species
-as one resource fails, we create another
-We redistribute resources that we need which allows us to grow past local recourse constraints

Recycling, Re-using, and Remanufacturing

all methods that humans can use to raise out local carrying capacity

Policies that affect Birth rates

Could be radical like China's one-child policy which directly affects that, but it could also be something like furthering women's rights and furthering economic status and urbanization of the population

What is fragmentation and how does it affect species Diversity

Population Overshoot

When a population goes past its carrying capacity and the limiting factors bring it plummeting back down to level out. Negative feedback restores equilibrium

Survivorship Curve

These are just the Type I, II, and III
I: Dies at old age
II: Equal chance of death any age
III: most likely gonna die young as fuck

Keystone Species and Predators in an environment

They are important because a cascade effect happens when they are removed from their habitat like the Yellowstone wolves case. If they are there, there is balance but once removed, the entire thing goes astray

Trophic Cascade

This is when a predator raises the survivorship of lower trophic levels by simply limiting the density of their prey, making it easier for the lower trophic levels to survive. It affects the ecosystem by maintaining the balance and not letting grazers go too far and take out too much.

The lincoln index

This is an equation that allows us to calculate population size from a sample. It is also the capture, mark, release, recapture and it works by
(#in 1st capture) * (# in 2nd Capture) / (# in 2nd Capture)

Difference Between Marx and Malthus thinking

To Marx, it wasn't the pressure of population growth on limited resources that was the issue, but rather how the capitalist mode of production put pressure on population growth. For Malthus, misery and destitution were caused by excessive population growth. Yes I looked this shit up.

Current Growth Rate for the Human Species

- For the World - 0.84% per year
-For the US - 0.1%

Why is it difficult to establish a carrying capacity for the Human Race?

Humans have a tendency to create innovation every time they are encroaching on a limiting factor and different policies are difficult to predict mathematically because they are all very subjective to the times and needs of nations

Long term implications of poverty on future population size

More poverty means high birthrates and likely overpopulation. Poverty can be eradicated with more even wealth distribution, furthering economic opportunity for everyone and making living expenses lower and affordable for everyone