Population Dynamics

Question 1

5000 bce

Answer 1

A modern form of agriculture emerged

(years ago) on the x-axis and world population size on the y-axis

Question 2

Global Footprint Network

Answer 2

On August 8th, 2016, the Global Footprint Network reported that the human population on earth had already consumed its yearly production.
e were borrowing three months of global production from the next year, 2017.

Question 3

Carrying capacity

Answer 3

population size for a given species that a specific environment can sustain indefinitely, given the food, habitat, water, and other necessary resources available.

“A finite world can support only a finite population; therefore, population growth must eventually equal zero.” (Garrett Hardin, “The Tragedy of the Commons,” 1968)

Question 4

Thomas Robert Malthus,

Answer 4

he power of population is indefinitely greater than the power in the earth to produce subsistence for man.”

Question 5

regulations on human population growth are either

Answer 5

voluntary (for example, birth control, abstinence, or delayed marriage)
involuntary (for example, famine, disease, or war).

Question 6

ecological footprint

Answer 6

measure of a person’s daily demands on the earth’s ecosystems.

It is the amount of biologically productive area of the earth (land and sea) needed to produce the resources a person consumes, in addition to the area needed to absorb and treat the resulting waste. It is measured in global hectares (gha).

Question 7

global hectare represent

Answer 7

A global hectare represents the biological productivity found on one “average” hectare (a measure of area)

Question 8

Populations change when

Answer 8

grow when birth rates exceed mortality rates. (birth rate > mortality rate)
shrink when mortality rates exceed birth rates. (birth rate < mortality rate)
remain stable when the two rates are similar. (birth rate = mortality rate)

movement through these stages is known as demographic transition.

Question 9

Demographic transition model stages

stage 1

Answer 9

Birth and mortality rates are similar, so the population size remains stable.

Question 10

Demographic transition model stages

stage 2

Answer 10

Mortality rates start to decline, but the birth rates stay relatively high. This causes the population size to start growing exponentially.

Question 11

Demographic transition model stages

stage 3

Answer 11

Birth rates are starting to fall and the decline in the mortality rates has levelled off. Birth rates are still higher than mortality rates, so the population is still increasing, but it is starting to slow down.

Question 12

Demographic transition model stages

stage 4

Answer 12

Birth and mortality rates are now similar again, so the population stops growing and eventually becomes stable.

Question 13

Demographic transition model stages

stage 5

Answer 13

If the birth rate continues to decline and falls below the mortality rate, then the population will enter stage 5.

Here, the population size starts to decrease because there are more deaths than births.

Question 14

Industrial Revolution 1700s

Answer 14

New machines and factories could make goods faster and more cheaply than ever before.
People migrated from farms into the growing cities to find work.
The Industrial Revolution brought a higher standard of living and lower mortality rates for many people.
Modern farm machinery and fertilization meant that more food could be harvested from the same amount of land, employing fewer people.
advances in sanitation, public health, and medicine led to a dramatic reduction in the mortality rate

As the Industrial Revolution progressed, the new lower mortality rates combined with traditionally high birth rates created a period of exponential growth

Question 15

Green Revolution.

Answer 15

Norman Borlaug helped improve agricultural productivity.
Food production increased around the world, so most people in developing countries no longer experienced regular periods of starvation. Mortality rates dropped, but just like in developed countries, birth rates remained high. This led to a period of exponential population growth.

Question 16

Future population trends

Answer 16

Slower growth stage 4 early stage 5
social and economic development
a lower risk of infant mortality
continuing urbanization

Question 17

Environmental consequences of human population growth

Answer 17

Pollution
climate change
over consumption (tragedy of the commons Garrett Hardin) and habitat loss

Question 18

Canadian social and economic aid

Answer 18

Formerly, it was done through the Canadian International Development Agency (CIDA)

Question 19

population

Answer 19

group of individual organisms of the same species that live together in the same geographic area.

always changing due to
new individuals are added through births (natality)
immigration (individuals moving into a population)
loss through death (mortality)
emigration (individuals moving out of a population).

Question 20

Population density (crude density)

Answer 20

how many individuals there are in a given area.

Question 21

Population dispersion

Answer 21

how the individuals are distributed over the area.

Question 22

ecological space (

Answer 22

size of the area that is actually usable by a species

o get a better estimate of how dense a population really is, biologists use ecological density (DE), which adjusts the area used in the calculation to reflect the amount of suitable habitat (SE) available for the species.

Question 23

Clumped dispersion

Answer 23

Clumped dispersion occurs when organisms group together in an area.

In animals clumped dispersion, may occur for:

protection
exploitation of a resource

Question 24

Uniform dispersion

Answer 24

that there is an equal spacing of individuals across an area
In animals, uniform dispersion can occur when each individual is guarding a similar-sized territory for feeding or nesting.

Question 25

Random dispersion

Answer 25

individuals are scattered randomly over an area.

Question 26

Quadrat sampling

Answer 26

used for counting abundant organisms, like plants, or organisms living beneath the soil, like earthworms, that do not move much and can easily be seen. one big square into smaller squares using a small square called a a quadrat

Question 27

type I survivorship

Answer 27

elatively few offspring, but each one has a high probability of living to the maximum age. Mortality rates are low and constant for most of their life, but then increase rapidly as they approach the maximum age. The parents generally invest a lot of energy in feeding, caring for, and teaching their offspring, who have a better chance of survival, as a result. Species showing type 1 survivorship curves include birds, humans, and other mammals.

Question 28

Type 2

Answer 28

pecies have a constant mortality rate throughout their life, so young and old have an equal chance of surviving
straight line down on angle

Question 29

Type 3

Answer 29

high mortality rate when they are young, but this declines as they grow older. Many species of fish and plants, as well as sea turtles, show this type of survivorship curve.
other way J

Question 30

fecundity.

Answer 30

number of offspring an individual can produce over its lifetime

Question 31

(abiotic

Answer 31

physical

Question 32

biotic

Answer 32

biological

Question 33

Closed Population

Answer 33

Not changed by immigration or emigration
Separated from other populations by long distances or are surrounded by physical barriers that prevent them from moving in and out of the population.
An island in the middle of the ocean is generally closed to immigrants that can’t swim or fly

Question 34

Open Population

Answer 34

Can be changed by immigration and emigration
No barrier preventing them from moving in and out of the population.
A population of moose in a patch of boreal forest in northern Ontario is considered to be an open population, because the moose can move in and out of it easily.

Question 35

net population

Answer 35

change in population size after the combined effects of births, deaths, immigration, and emigration are accounted for.
Net population change = (b + i) – (d + e)

Question 36

The four factors that affect population dynamic

Answer 36

births
deaths
immigration
emigration
Population dynamics are the result of an interaction between:

internal factors (for example, reproductive ability)
external factors (for example, weather, food supply, predation, and disease)

Question 37

Geometric growth

Answer 37

It happens in populations where individuals can only breed once per time period (like deer, which breed once per year).
On Day 0, the population size is 1. On the next day, it doubles to 2 and the day after that, it becomes 4, and so on.

graph like a J

Question 38

exponential population growth

Answer 38

humans, can reproduce at any time of the year. This means that the population can grow continuously, since it is not restricted to fixed time periods

Question 39

Biotic potential

Answer 39

maximum population growth rate that could occur under ideal conditions for an organism.

Question 40

logistic growth

Answer 40

closely resembles what happens in natural populations
The Lag phase
The Log phase
The Stationary phase
s curve or sigmod curve

N is the population size at time t
r is the growth rate per individual
K is the carrying capacity

Question 41

Phase of logistic population: First part of the curve lag

Answer 41

Population is slowly building up

Increase in population size is slow, because the population is still small.

Question 42

Phase of logistic population: 2nd part of the curve log

Answer 42

Population increases geometrically or exponentially

Since there are enough resources to meet the needs of the population, population growth rate reaches its maximum and biotic potential.

As the population increases, it begins to run out of resources such as food, water, and space. Numbers increase until there are no longer enough available resources to maintain the high rate of population increase. At this point, the population growth rate begins to slow down and eventually stops when the population size reaches its carrying capacity (K).

Question 43

Phase of logistic population: last part of curve - stationary

Answer 43

Population approaches its carrying capacity because

number of births = number of deaths

Eventually a dynamic equilibrium around its carrying capacity is maintained as

population growth rate = 0

Question 44

density-dependent factors

Answer 44

internal factors
For animals, these factors can include:

the amount of food
breeding territory available
social dynamics
predator avoidance opportunities
the risk of parasites and disease, and so on.

For plants, the availability of resources like sunlight, water, and soil will depend on how many other plants are competing for them in the same area.

Question 45

Density-independent factors

Answer 45

abiotic factors such as:

Extreme weather events
Fires
Droughts
Volcanic eruptions
Pollution

Question 46

Levels of organization in ecological systems

Answer 46

Individuals form the lowest level of the hierarchy.
Populations are formed at the next level when individuals of the same species combine.
Communities form when populations of different species interact.
Ecosystems are formed when communities interact with each other, and with other biotic and abiotic processes.

Question 47

niche

Answer 47

How an organism uses its habitat, and the way it utilizes the resources within it

Question 48

Competition

Answer 48

two or more organisms are using the same set of resources in the same area to the disadvantage of each.
the interaction results in a negative outcome for each organism.
Competition can defined as:

Interspecific: between members of different species.
Intraspecific: among members of the same species

Question 49

interference competition

Answer 49

two animals fighting over a resource

Question 50

explotive competition

Answer 50

one animal eats all the fruit off the tree before the others can get to it

Question 51

resource partitioning

Answer 51

Similar species that share the same area usually divide up the resources

Question 52

morphological defence

Answer 52

involving the shape or structure of an organism.

thorns, spines, and stinging spikes

Question 53

Chemical defence

Answer 53

Animals and plants have evolved chemicals that they can use to reduce predation.

For example, skunks can spray a noxious-smelling chemical

Question 54

Cryptic colouration (or camouflage)

Answer 54

to hide themselves from predators.

Question 55

Aposematic colouration:

Answer 55

warn predators that they are not good to eat. Instead of trying to hide from predators, these species have evolved dramatic colour displays to warn predators

Question 56

Symbiosis

Answer 56

two species may live closely together and interact in ways that benefit at least one of the species.

Mutualism occurs when both participating species benefit from living closely together
commensalism-one species benefits while the other species does not (but is also not harmed)
Parasitism - micro or macro parasites

Question 57

social parasitism

Answer 57

This does not involve a parasite consuming resources from its host’s body. Instead, the parasite manipulates the social behaviour of the host.

Question 58

brood parasitism

Answer 58

A dramatic example of social parasitism is when a bird’s nest is taken over by another bird that uses the nest for its own eggs.

Question 59

producers

Answer 59

Green plants like algae, pond lilies, and reeds

Question 60

main primary consumers.

Answer 60

fish, insect larvae, and crayfish,

Question 61

Secondary consumers,

Answer 61

leopard frogs, carnivorous fish (for example, bass), and insects (for example, water beetles) eat the herbivores

Question 62

tertiary consumers,

Answer 62

predatory birds (for example, the blue heron) eat the primary consumers (for example, crayfish), as well as the secondary consumers (for example, leopard frogs and bass).