INDEPENDENDT STUDY UNIT
POPULATION DYNAMIC
 CHARECTRICTIC OF POPULATION
 MEASURING MODELING POPULATION
CHANGE
 FACTORS EFFECT POPULATION CHANGE
OZLEM TER
POPULATION DYNAMICS PART I
1. A) In order to study populations, scientists need to be able to describe a population.
What are three different measurements uses to describe population?
Scientists use to describe populations by observing dispersion patterns by determining the size
and density of population. Population dispersion is different species lives in the same
geographical area and rival for food, space and other resources. Population size represents
number of individual in one area. Density population represents the number of individual per
unit area or volume.
B) Defend term ‘population size’ and ‘population density’ how these two terms differ from
one another?
Population density is number of the individual within the geometrical boundaries or gene pool
either per unit area or volume. It is depend on total number of individual and area occupied by
the population because it is measured by mathematical formula.
Formula of population density
Population of density = total number of individual____
Area occupied by the population
Population size represents number of the individuals within the geographical area and gene pool.
It depends on birth, immigration, deaths and emigration. Population size can be measured with
mathematical formula as well. Result of the measurement identifies population size growth or
population decline.
Formula of population size
Population change = [(births + immigration) – (deaths + emigration)] x 100
Initial population (n)
Population size identifies that total number of individuals living in specific area such as country,
but population density gives information about number of individuals in square kilometer or mile
such as city. Population of people in Canada is population size but population of people in
Toronto is population density.
C) An area measuring 1000 ha (1 hectare =10,000 m2) has 200 wolves in it. What is the size
of this population? What is the density of this population?
Population terms
Population of density is D
Formula of population density is
Total number of individual is N
Area occupied by the population is S
D = __N__
S
D =?
S = 1000 ha (1 hectare 10,000 m2)
D = _N_ = _ 200__
S
1000
N = 200 wolves
= 0.2 wolves/ha
Population size is 200 wolves in 1000 hectare.
3. What is meant by the term ‘population dispersion’?
Population dispersion observes different species in the same geographical habitat. It helps to
explain how individuals disperse in area by using clump, uniform and random patterns of
distribution. Clump dispersion observes population to be found in tight cluster such as fish;
uniform dispersion observes the population to be found specific area depending on species
ability to be survived easily such as penguin; random dispersion is tendency for population to
take space randomly such as plant – maple trees.
Clump dispersion
uniform dispersion
random dispersion
POPULATION DYNAMICS PART II
1. A) Explain what is meant by the term ‘environment’?
Environment is part of the ecosystem and ecology use term environment to explain
communication organism and their surrounding area. It composes of abiotic and biotic resources.
Environment can be classified with physical, chemical and biological environment. These terms
are used to identify organism and their relationship between their surrounding areas. It includes
all organism, weather, water, sunlight, air, sea level, high altitudes etc…
B) Describe some biotic resources that may be limited in an ecosystem at any time.
Biotic factor is major point for balance the population in ecosystem. It is important for
maintaining of population. Symbiosis, disease, predation are example of biotic resources. If the
population of predator decreases, population of prey increases mean timely that affects the
stability of population. For instances, grasshopper is primary consumer and it consumes plant,
frog is secondary consumer which consume grasshopper, on the other hand frog is consumed by
snake in food chain then snake is consumed by hawk. Any disorder in the stable food chain can
cause to diminish efficiency of other animals’ food resources. It is significant because ecosystem
compose of large food chain and one animal important for another in order to provide stability.
Also decomposer bacteria that help to break down death plants and animals bodies are another
significant point in the food chain for nitrogen cycle. If any problem occurs in this chain plant
cannot be able to produce food. These example indicates how important to one livings thing for
another. Thus varieties of all living thing are affected by biotic factor.
Graph of food chain
grass
bacteri
a
grassh
oppers
howk
frogs
snake
B) Describe some abiotic resources that may be limited in an ecosystem at any one time.
Abiotic resources can be limited factor as well. Amount of the sunlight, liquid, temperature and
temperature range, type of soil or rack, pH level, carbon and nitrogen cycle, carbon, oxygen,
nitrogen, iron, calcium and other minerals are very important because they are needed by all
living thing. If ecosystem does not have adequate of these abiotic resources, many diseases occur
meant time. Sunlight and water major are important factors for creation of ecosystem. Is that
possible to think about biosphere without sunlight and water? As known very well, word cannot
be exist or survive without both of these abiotic natural resources. Plant cannot produce glucose
to provide other animals. Generally, medicine is produce from plant and other minerals, any
disorder will affect industry as well.
Abiotic and biotic resources connect each other for survival, carrying capacity; therefore, they
can be limited factor as well.
2. A) what is mean by the term “carrying capacity of a population”?
Carrying capacity is maximum number of individuals which is given species in an area with
sustainable resources. In ecosystem carrying capacity is maintaining the population of species
according to limited factor. Stability of population is advantage for all species. Any unbalancing
in the ecosystem can cause serious problem in population such as extinction of species. Carrying
capacity is one of the momentous term to help considering any unbalance in ecosystem. Carrying
capacity is stable when range of births is equal to range of deaths.
B) Is the carrying capacity the same for all species? For all population of the same species?
Discuss!
Generally, it should be the same for all species but humans’ population size damage stability of
carrying capacity. The role of carrying capacity is balance of number of births (fertility) and
deaths (morality). Even though number of predator and number of prey change over time, they
can protect their stability. When number of predators increase, number of preys decrease
distinguishably; the stage shows increasing time for one population causing to diminish time for
another animal population depending competition. The range of human population is different;
the reason is the capability of technology that gives opportunities to human changing or creating
their range. For instance, they use some chemical to produce their food and increase number of
cows, cats, horses, sheep, dogs etc…and also increase certain plants as well like wheat, rise, and
fruit. Human population is developed by technology even though reducing human power in
working area. Technology helps to produce important equipment such as gun or chemical agent
in order to damage carrying capacity, therefore, human population increasing every year.
C) What sorts of things determine the capacity of an ecosystem?
Carrying capacity is balance efficiently and death, birth, diseases, biotic or abiotic factor, range
of emigration and immigration are sort of the things determine the capacity of an ecosystem. If
the average of birth increases, the number of predator and prey can effect very fest in sort time
but decreasing one population by another cause the decreasing its population as well. This rate
helps to protect stability of population. Food resources, predator and prey can be limited factor
for specific species. After short time population of species reach carrying capacity. Disease,
completion, predation, symbiosis, biotic and abiotic factor determine the carrying capacity.
Competition of prey and predator
Increasing prey (moose) ------ increasing food for predator (wolves) ------ population predator
(wolves) increasing ------ population of prey decreasing (moose) ------- population of predator
decreasing (wolves) because food resources become limited!
D) In general, what happens to the resources of an ecosystem as a population increases in
size?
Population density (D) =_ _ total numbers of individuals (N)__
Area occupied by the population (S)
When the population increases in size, resources decrease. As seen clearly from the equation,
population change increases and causes the lack of place for other population. According to
number of the individual food resources decrease. But theory of ecosystem that is everything in
balance and it has perfect food chain in the wild life, therefore, deer and tiger graph or another
food chain between grasshopper, frog, snake and hawk show that they have carrying capacity.
The other hand, human population increases day to day that cause to adequate food resources and
space, thus, people move step by step to wild animal spaces and also negative effect of
technology damage the wild live as well. These cause to chance stability of ecosystem. In China
population size is large this cause lack of space for living, therefore, government tries to reduce
average of birth by obtain some rules.
6. How does the number of offspring that are produce by an individual typically compare
with the fecundity of that individual? What sort of factor s create this discrepancy
Number of offspring that is produced by an individual compares with the fecundity of that
individual because economic condition forces individual to diminish number offspring in the
next generation. This can be observed from different social environment or generation to
generation. For instance, in China, government tries to reduce average of birth in order to
increase their life standard. According to technology and developing industry, less power of
human in working environment cause to diminish offspring in order to provide enough food
resources and space to live. When the technology and industry did not develop as today, number
of offspring is larger than nowadays. In developing country is number of offspring have already
started to reduce because better to provide enough food resources and shelter for them instead of
having large number of offspring. Limiting reproductive potential depends on other limiting
factor such as biotic and abiotic resources. If the plant could not provide enough mineral and
water from the soil its reproductive potential decreases. It cannot produce enough pollen for its
season. In order to become useful, plant need get enough sunlight, mineral and other condition.
Size and number of offspring is important for plant. For insect and other animal such as fish,
frogs is important to produce as much as possible because it gives chance to be successful to be
survival.
POPULATION DYNAMICS PART III
1. A) What is density depending factor?
Density depending factor is where can affect population size or density in a geographic area
depending on real population density to cause unstable condition over the population in an
ecosystem. For example, disease is one of the density depending factors over population. It can
affect region where large population can dwell. It reduces size of population in area and it can
pass from plant to animal or animal to humans. For example, SARS, Severe Acute Respiratory
Syndrome, affected many people in China.
B) List three different density depending factor.
Competition (intraspecific competition): competition is important depending factor. It can be
seen in animal population. Role of this strong animal will survive but weak animal will die.
Disease: it can be occur over crowded population. SARS affected many Chinese people between
2002 and 2004. It can find host easily to reproduce faster.
Predation: consuming of prey by predation such as tiger and deer
C) How did Charles Darwin use the concept of density depending factors in the Theory of
Evolution?
Charles Darwin created and developed Theory of Evolution during his voyage in Galapagos
Island. He thought ‘why Galapagos finches have large population size’. Animals’ adaptation
depends on the food resources such as plant and insect. Variant of finches help to Darwin for
using dependent factor. He decided that dependent and independent factor affects this variation.
Dependent (biotic) factor is food resources, spaces predation; independent (abiotic) factor is
sunlight, temperature, water and other important element which take space in air or in soil.
Galapagos Island absorbs more sunlight this increases population of plant in this area. According
to large population of plant, population animal increases as well. This is basically classified
natural selection and adaptation.
2. A) Distinguish between intraspecific competition and interspesific completion.
Itraspecific completion is between the same species such as male spider and female spider or
completion between the same the same type of plant because of water, nutrients, light or space.
Interspesific completion; it occurs between different species such as tiger and deer or frog and
snake because of food resources.
B) What are some of the potential consequences to the population as the density of the
population increases?
Density of population increases when number of individual increasing in the specific area.
Number of individual alters according to rate of births, deaths, emigration and immigration.
Biotic and abiotic factor can be limiting factor for the population density. As bellow some of the
depending factors were explained;
-Competition can occur between the same species or different species.
-Predator provide its food from other species
-Prey is hunted by predator; food for other species.
-Disease is caused by virus to reduce human, animal or plant population in specific region.
-Allee effect occurs when death rate is bigger than births rate. When small species cannot find
mate for reproduction.
-Pollution that cause by human effect greenhouse gasses
Note: all of dependent factor is controlled by independent factor because without sunlight, water,
mineral and atoms life cannot exist!
4. A) What is density independent factor?
A factor has an effect on size of a population and affects independently or anyhow of the
population density. Abiotic factor is independent factor for population and it includes sunlight,
rate of temperature, water, earthquake, forest fire, minerals and pollution.
B) What are two (supposedly) examples of density independent factors? Provide specific
examples.
Sunlight is most important factor for all living things. All organism need sunlight because
sunlight natural heat which help to provide and protect stability of life. Without sunlight people
cannot live in an ecosystem and plant cannot able to produce food. According to photosynthesis
and constancy of live, sunlight is major important density independent factor.
Water is another important issue of density independent factor. Most of organisms need water
for instance, without water human cannot exist because human and animal need water to provide
chemical reaction inside body in order to live or consume. Plant needs water for photosynthesis
and as known very well plant occupies trophic level in food pyramid. Primary consumer
secondary, consumers, tertiary consumer and quaternary consumer need plant due to continue
protecting stability of live.
C) What is meant by the term ‘biomagnification’?
Biomagnification is processes in an ecosystem which identifies higher concentration of chemical
particle moving from prey to predator in food web. Higher concentration of toxin cannot be
broken dawn by decomposition bacteria and it remains in soil or water in order to be taken by
another organisms. This certain unconverted particle is absorbed by plant or taken by animal. It
cannot be broken down in animal body or plan structure as well. It passes from one to another
like a cycle. According to food web, primary, secondary, tertiary and quaternary consumers need
to eat for continuing their life. They need eat a lot which means each consumers include higher
level toxin when eat another organism. Thus, concentration of toxin becomes very important
according to consumers rate.
D) Why are top level carnivores so susceptible to such things as pesticide use?
According to biomagnification process carnivores have larger toxic particle in their body.
Carnivores need to eat herbivorous or another carnivores in order to live and regulate their
population. Herbivorous need to eat producer each organism obtain toxin from soil, water or
other animal. When toxin is taken from water or soil, it is able to move other trophic level in
food webs and it can combine with another toxin, therefore, concentration of toxin increase when
moving in food webs. Basically, when size of animal increases, concentration of toxin increases
too. In the food web, carnivores are top of the food chain, quaternary consumer. For example,
humans are carnivores and they eat producer, primary, secondary, tertiary or quaternary
consumers. Thus toxin moves from one level to another and humans obtain more toxin than
producer or herbivorous.