# Which is a Density-dependent Factor Apex

Which is a Density-dependent Factor Apex.

## Population Regulation

Have y’all always wondered why populations of organisms in nature do not keep to grow and expand endlessly? Perhaps you have wondered what factors forbid populations of organisms from growing exponentially? In the following article, we will discuss how populations are regulated, which factors are involved, and how it relates to united states as humans.

## Definition of population regulation in ecology

Every living organism on Earth (including humans) has limits to how big its population grows. Infinite growth is not possible on a planet with finite resources and all populations volition eventually be regulated. This article covers the mechanisms of
population regulation.

Population regulation
refers to the ecological processes (biotic and abiotic factors) past which the growth of populations is limited due to the furnishings on birth and death rates.

The ecological factors that limit population growth are known as
limiting factors. There are ii different kinds of limiting factors –
density-dependent
and
density-independent
limiting factors. In addition, at that place are 2 kinds of population regulation –
top-down regulation
and
bottom-up regulation.

## Density-dependent limiting factors

Density-dependent
limiting factors touch a population’s per capita charge per unit of growth based on the population’s density. These factors volition more often than not cause the
growth charge per unit to drop as the population gets larger. Density-dependent limiting factors usually cause populations to achieve a maximum level (chosen the population’southward
carrying chapters).

At this indicate, the population size will level off and usually, but not always, become stable. This is known as
logistic growth
(Fig. 1). When a population’s growth rate remains constant, no matter its size, it will keep to grow larger at an exponential rate. This is known as
exponential growth. This is very rare, and when information technology does occur, it will ordinarily be apace corrected past the density-dependent limiting factors in the environment.

Effigy 1: The logistic growth model. Source: Wiki Commons

Logistic growth
occurs when density-dependent limiting factors cause population growth to gradually slow before reaching a maximum level at which growth will level off and go stable.

Exponential growth
occurs when a population’s growth rate remains constant, no affair the size, exceeding its carrying capacity.

Most density-dependent limiting factors are
biotic. These factors can include intra – and interspecific contest, increased spreading of affliction, and parasitism. In prey species, higher population densities may as well result in higher predation rates. Individuals from a population that has reached carrying capacity may too wander out in search of new habitat that is not still at chapters.

Biotic: Biotic factors are those that involve or are produced past living organisms.

Abiotic:
Abiotic factors are those that practise non involve and are not produced by living organisms.

By the early 1970s, saltwater crocodile (Crocodylus porosus) populations in Australia’s Northern Territory were nearing extinction, with only a few thousand individuals remaining. Thanks to protective efforts, over the post-obit decades, the population recovered to the point that virtually rivers are believed to accept reached carrying capacity, with crocodile populations nearly reaching pre-exploitation levels, leveling off, and becoming stable.

In this case, the density-dependent limiting factors include competition (e.g., finite casualty availability and territoriality) and habitat limitations (e.thousand., convenance habitat and climatic restrictions), which forbid the crocodile population from connected expansion. In many of these rivers, this has resulted in smaller, less dominant males wandering out into the ocean and into suboptimal areas in search of new habitats, oftentimes bringing them into conflict with humans.

### Population cycles

Populations experiencing density-dependent limiting factors often experience
instability at carrying capacity, even without the effects of density-independent limiting factors. These populations may experience cycles of growth followed past a reduction in size in oscillating patterns called

cyclical oscillations. Under specific circumstances, usually involving multiple species, these oscillations are driven by density-dependent limiting factors such as predation and resources abundance.

## Density-contained factors

Density-independent
factors impact the per capita population growth rate
regardless
of the population’due south density. Since these factors do not depend upon the population’s size, their impact does not corporeality to the “correction” that density-dependent factors bring to a population. In other words,
density-contained factors can be potentially catastrophic to smaller populations, particularly populations of a species with a limited geographic range.

Density-contained factors can exist
abiotic, and perhaps the all-time example of a density-independent gene would be a
natural disaster, such as a forest burn down. A natural disaster may kill a meaning fraction of a population living in the area, regardless of how large that population was to begin with. If the population is limited to but a pocket-size surface area, a unmarried natural disaster could even push button a species to extinction.

For example, black bear (Ursus americanus) populations are known to exist affected by wildfires past style of decreased cub survival.

## Top-downward population regulation

Elevation-down population regulation
refers to situations where species at college trophic levels (e.chiliad., noon predators at the top of the food chain) control the populations of species at lower trophic levels (e.1000., prey). Due to this, it is too called “predator-controlled” regulation. Typically, the population size and density of the apex predator at the top of the food chain is much lower than that of its prey, which are usually quite abundant. Occasionally this may non be the case, as is seen with the American alligator (Alligator mississippiensis) and caiman species, which are apex predators and are frequently very abundant.

For example, mountain lions (Puma concolor) may control mule deer (Odocoileus hemionus) populations, simply the mule deer may control the populations of certain establish species.

## Bottom-up population regulation

Lesser-upwards population
regulation
is dependent on the
resources of an ecosystem. Since all of the higher trophic levels are dependent on the continued presence of those below them, when those resources at the lower level are diminished or absent, all trophic levels are affected (Fig. iii).

For example, if vegetation experiences a mass die-off, this may result in a decline in the mule deer population due to starvation. This, in plow, may also upshot in a reduction in the mountain lion population due to a lack of casualty.

Figure ii: The different trophic levels. Bottom-upwards regulation involves the primary producers and how they impact each successive level. Top-downward regulation involves the college trophic levels regulating the lower levels. Source: EcoIntelligent

## Population regulation in humans

Fifty years ago, in 1972, the homo population consisted of around 3.nine billion people. Today that number has grown to over seven.9 billion (Fig. two). Thus, the human population has more than doubled, growing more in the last half-century than in the entirety of homo existence (at least 200,000 years). This exponential growth is largely due to better technology, food availability, medicine, and more than, which have allowed humans to
artificially increase their carrying capacity.
Still, this exponential cannot persist indefinitely, as the methods used to increment our carrying chapters are being outpaced by many density-dependent limiting factors. For humans, these limiting factors include widespread resource depletion (food, water, gas), climate change, increased spread of disease, and pollution.

Figure iii: Man population growth since 1800, including time to come high and low projections. Source: Wiki Commons

Indeed, the consequences of these density-dependent factors accept always been present, but their impact will continue to be amplified as the population further exceeds the natural carrying capacity. Density-independent factors
also
touch human populations, with some notable recent examples including earthquakes, hurricanes, and tsunamis that cause large-calibration damage to infrastructure and loftier mortality. To counteract this growth and mitigate consequences, bogus methods of human population regulation take been proposed, including increased access to contraception, family unit planning, and increased pedagogy.

## Population Regulation – Primal takeaways

• Population regulation

refers to the ecological processes (biotic and abiotic factors) by which the growth of populations is express, due to the effects on nascency and death rates.
• There are ii different kinds of limiting factors-

density-dependent

and

density-independent

limiting factors.

Density-dependent limiting factors
impact a population’southward per capita rate of growth based on the population’s density.

Density-contained factors
impact the per capita population growth rate regardless of the population’due south density.

• There are two kinds of population regulation: peak-downwards and bottom-upward
.

Top-downwardly population regulation
refers to situations where species at higher trophic levels control the populations of species at lower trophic levels.

Bottom-upward population regulation
is dependent on the resources of an ecosystem.
• Populations may experience cycles of growth followed by a reduction in size in aquiver patterns, called

cyclical oscillations
.

## Ofttimes Asked Questions near Population Regulation

Elevation-downwardly population regulation
refers to situations where species at college trophic levels (e.yard., apex predators at the top of the nutrient concatenation) control the populations of species at lower trophic levels (eastward.g., prey). Due to this, it is also called “predator-controlled” regulation.
Bottom-upward population
regulation
is dependent on the
resources of an ecosystem. Since all of the higher trophic levels are dependent on the continued presence of those beneath them, when those resource at the lower level are diminished or absent, all trophic levels are affected.

There are two kinds of population regulation –
height-downwards regulation
and
bottom-up regulation.
Elevation-downwards population regulation
refers to situations where species at higher trophic levels (e.g., noon predators at the top of the food chain) control the populations of species at lower trophic levels (due east.g., prey). Due to this, it is too called “predator-controlled” regulation.
Lesser-up population
regulation
is dependent on the
resources of an ecosystem. Since all of the college trophic levels are dependent on the continued presence of those below them, when those resource at the lower level are macerated or absent, all trophic levels are afflicted. For humans, density-contained factorslikewise
affect human populations, with some notable recent examples including earthquakes, hurricanes, and tsunamis that cause large-scale damage to infrastructure and high mortality. To counteract this growth and mitigate consequences, bogus methods of human population regulation have been proposed, including increased access to contraception, family unit planning, and increased didactics.

Population regulation
refers to the ecological processes (biotic and abiotic factors) by which the growth of populations is limited due to the effects on nascence and death rates.

There are ii kinds of population regulation –
top-down regulation
and
bottom-up regulation.
Top-down population regulation
refers to situations where species at higher trophic levels (e.chiliad., noon predators at the top of the nutrient chain) control the populations of species at lower trophic levels (east.g., prey). Due to this, it is besides called “predator-controlled” regulation.
Lesser-upwards population
regulation
is dependent on theresource of an ecosystem. Since all of the college trophic levels are dependent on the continued presence of those beneath them, when those resources at the lower level are macerated or absent, all trophic levels are afflicted.

Density-dependent
limiting factors impact a population’s per capita rate of growth based on the population’s density. These factors volition mostly cause thegrowth rate to drop as the population gets larger. Density-dependent limiting factors usually cause populations to achieve a maximum level (called the population’scarrying capacity).Density-independent
factors impact the per capita population growth rate
regardless
of the population’s density. Since these factors do not depend upon the population’southward size, their impact does not amount to the “correction” that density-dependent factors bring to a population. In other words,
density-independent factors can be potentially catastrophic to smaller populations, peculiarly populations of a species with a express geographic range.

## Final Population Regulation Quiz

Question

True or False: Every living organism on Earth has limits to its population size.

Testify respond

Question

The ecological factors that limit population growth are known equally…

Question

The two types of limiting factors are…

Show respond

Density-dependent and density-independent

Testify question

Question

Density-dependent limiting factors…

Impact a population’s per capita charge per unit of growth dependent on the population’s density.

Show question

Question

Which are examples of density-dependent limiting factors?

Limitations on the food supply within an ecosystem.

Testify question

When density-dependent limiting factors cause population growth to gradually slow before reaching a maximum level at which growth volition level off and become stable.

Evidence question

Question

What is exponential growth?

When a population’s growth charge per unit remains constant, no matter the size, exceeding its carrying capacity.

Show question

Question

Density-independent limiting factors…

Touch on a population’s per capita charge per unit of growth contained of the population’due south density.

Show question

Question

Summit-down population regulation refers to…

Situations where species at higher trophic levels control the populations of species at lower trophic levels.

Evidence question

Question

The cycles of growth followed by reductions in size are called…

Question

Truthful or Fake: The human population has a carrying capacity.

Evidence respond

Question

The human population has _____ in the terminal half century, which is more than in information technology has in the previous _____ years.

more than than doubled; at to the lowest degree 200,000

Show question

Question

What are some of the density-dependent limiting factors affecting the homo population?

Question

If vegetation experiences a mass die-off, this may result in a reject in the mule deer population due to starvation. This, in plow, may also result in a reduction in the mountain king of beasts population due to a lack of prey. This is known as…

Bottom-up population regulation

Prove question

Question

Mountain lions may control mule deer populations, merely the mule deer may control the populations of certain establish species. This is known as…

Top-downwards population regulation

Show question

Question

True or False: Logistic population growth is rare in nature.

Question

Which is true about logistic population growth?

The population’due south growth charge per unit slows as it approaches carrying capacity.

Testify question

Question

What are the 2 types of population growth?

Question

What are the ii types of limiting factors?

Show respond

Question

What is an instance of a mammal species that has experienced exponential growth in its population?

Question

Exponential growth is nigh often seen when?

In experimental settings with bacteria

Show question

Question

The virtually common blazon of population growth is-

Question

A population’s largest size, dictated by resources limitations and other limiting factors, is its-

Show respond

Question

Which are examples of density-dependent limiting factors?

Competition with some other species

Show question

Question

Near all naturally occurring populations experience…

Respond

Logistic population growth

Evidence question

Question

Logistic population growth produces a __________ curve.

Question

What density-dependent limiting factors prevent American alligator range expansion and farther population growth?

Competition with some other crocodilian species

Show question

Question

What is one density-independent limiting cistron that prevents American alligator range expansion and further population growth?

Question

Logistic population growth occurs when a population’s per capita growth rate _________ as its size ________.

Show respond

Question

What is the equation for logistic population growth?

Question

Limiting factors

are referred to as weather condition or resources inside an environs that _____ population growth.

Question

Truthful or fake:
population growth
is the change in size of a population over a certain period of time.

Question

The

carrying capacity

is the  _____ number of individuals of a given species that an environment can support.

Question

The ______ of a system is limited by limiting factors.

Question

____
factors are nonliving factors in an ecosystem such as temperature, sunlight, nutrients, water, pH, salinity and humidity.

Question

_____ factorsare living factors such as competition for resources, predation, and disease.

Question

_________are mostly biotic factors whose effects in
population size
depend on population density.

Prove respond

Density-dependent factors

Show question

Question

________ competition
is the competition for limited resources between individuals of the same species.

Question

________ competition

is the competition for limited resources betwixt individuals of
unlike
species.

Question

Diseases and parasitism are both examples of _____________.

Show respond

Density-dependent limiting factors

Testify question

Question

The competitive exclusion principle states that:

no two species can occupy the same niche

Show question

Question

_____ limiting factors
are usually abiotic factors that limit a
population size
regardless of population density.

Question

True or false: The effects of
weather change

in the population of aphid insects

is an example of density-dependent limiting factor.

## Study Plan

Exist perfectly prepared on time with an private program.

## Quizzes

Test your noesis with gamified quizzes.

## Flashcards

Create and find flashcards in tape time.

## Notes

Create cute notes faster than ever before.

## Report Sets

Accept all your study materials in ane identify.

## Documents

Upload unlimited documents and salve them online.

## Study Analytics

Identify your study strength and weaknesses.

## Weekly Goals

Set up individual study goals and earn points reaching them.

## Smart Reminders

Stop procrastinating with our study reminders.

## Rewards

Earn points, unlock badges and level upwardly while studying.

## Magic Marker

Create flashcards in notes completely automatically.

## Smart Formatting

Create the most cute written report materials using our templates.

subtopic-ab

## Which is a Density-dependent Factor Apex

Source: https://www.studysmarter.us/explanations/biology/ecology/population-regulation/