Download •A population is a group of organisms, all of the same species, that

4.1 NOTES
•A ___________________ is a group of organisms, all of the same species, that live in a specific area.
•Populations of organisms, do not experience ___________________ growth. Rather, the graph of a
growing population starts out slowly, then begins to resemble a ___________________ curve.
•A J-shaped growth curve illustrates ___________________ population growth. Exponential growth
means that as a population gets larger, it also grows at a faster rate.
___________________, such as availability of food, disease, predators, or lack of space, will cause
population growth to slow.
•Under these pressures, the population may stabilize in an ___________________ growth curve.
•The number of organisms of one species that an environment can support indefinitely is its
___________________ .When a population overshoots the carrying capacity, then limiting factors may
come into effect.
•Biologists study the factor that determines population growth—an organism’s reproductive pattern, also
called its ___________________
___________________ life-history patterns are common among organisms from changeable or
unpredictable environments. Rapid life-history organisms have a small body size, mature rapidly,
reproduce early, and have a short life span.
•Large species that live in more stable environments usually have ___________________ life-history
patterns. Slow life-history organisms reproduce and mature slowly, and are long-lived. They maintain
population sizes at or near carrying capacity.
Density factors and population growth
Three ___________________ of dispersal are random, clumped, and uniform.
Ecologists have identified two kinds of limiting factors that are related to dispersal:
___________________ and ___________________ factors. Population density describes the number of
individuals in a given area.
Density-dependent factors include ___________________, competition, predators, parasites, and food.
Disease, for example, can spread more quickly in a population with members that live close together.
Density-independent factors can affect ___________________ populations, regardless of their density.
Most density-independent factors are ___________________ factors, such as temperature, storms, floods,
drought, and major habitat disruption.
When a ___________________ consumes prey on a large enough scale, it can have a drastic effect on the
size of the prey population.
___________________ is a density-dependent factor.
•When a population increases to the point at which demand for resources exceeds the supply, the
population size ___________________
•When populations of certain organisms become crowded, individuals may exhibit symptoms of
__________________. As populations increase in size in environments that cannot support increased
numbers, individual animals can exhibit a variety of stress symptoms.
•These include ___________________, decrease in parental care, decreased fertility, and decreased
resistance to disease. They become limiting factors for growth and keep populations below carrying
capacity.
5.1 NOTES
___________________ refers to the variety of species in a specific area.
•The simplest and most common measure of biodiversity is the number of ___________________ species
that live in a certain area.
___________________ increases as you move toward the equator.
The richest environments for biodiversity all seem to be ___________________ places: tropical rain
forests, coral reefs, and large tropical lakes.
Living things are ___________________. •Living things can be ___________________ for other living
things.
Scientists do know that if a species is ___________________ from an ecosystem, the loss may have
consequences for other living things in the area.
___________________can bring stability to an ecosystem.
Another important reason for maintaining ___________________ is that it can be used to improve people’s
health.
___________________is the disappearance of a species when the last of its members dies.
There is also a certain level of natural extinction, called ___________________extinction, that goes on.
Scientists estimate that background extinction accounts for the loss of one to ___________________per
year. However, the current rate of extinction exceeds that by many times.
A species is considered to be an _______________________when its numbers become so low that
extinction is possible. When the population of a species is likely to become endangered, it is said to be a
___________________ species.
One of the biggest reasons for decline in biodiversity is ___________________ loss.
Habitat ___________________ is the separation of wilderness areas from other wilderness areas.
Habitat fragmentation has been found to contribute to:
increased extinction of local species, changes in overall biodiversity, disruption of ecological
processes, new opportunities for invasions by unwanted or exotic species, increased risk of fire.
The smaller the fragment, the ___________________ biodiversity the area can support.
Geographic isolation can lead to genetic ___________________.
The edge of a habitat or ecosystem is where one habitat or ecosystem meets anoth er.The different
conditions along the boundaries of an ecosystem are called ___________________.
Another threat to biodiversity is habitat ___________________, the damage to a habitat by pollution.
Three types of pollution are air, water, and land pollution.
Burning ___________________is also a major source of air pollutants such as sulfur dioxide.
Acid precipitation—rain, snow, sleet, and fog with low pH values—has been linked to the deterioration of
some forests and lakes.
The ___________________in this region—known as the ozone layer—absorbs some of the ultraviolet
waves striking the atmosphere, reducing the ultraviolet radiation reaching Earth’s surface.
Water pollution degrades aquatic habitats in streams, rivers, lakes, and oceans.
Excess fertilizers and animal wastes are often carried by rain into streams and lakes.
The sudden availability of nutrients causes ___________________, the excessive growth of algae.
Exotic species- People sometimes introduce a new species into an ecosystem, either intentionally or
unintentionally. These species can cause problems for the ___________________ species. When exotic
species are introduced, these species can grow at an ___________________rate due to the fact that they are
not immediately as vulnerable to local competitors or predators as are the established native species.
5.2 NOTES
___________________biology is the study and implementation of methods to protect biodiversity. Natural
resources include sunlight, water, air, and plant and animal resources.
In response to concern about species extinction, the _________________________became law in 1973.
This law made it illegal to harm any species on the endangered or threatened species lists.
A ___________________is the physical location where an organism lives and interacts with its
environment. Establishing parks and other protected regions has been an effective way to preserve
ecosystems and the communities of species that live in them.
A general strategy for protecting the biodiversity of an area probably is to protect the largest area possible.
Therefore, another strategy for preserving biodiversity is to connect protected areas with
_________________________. • Habitat corridors are protected strips of land that allow the migration of
organisms from one wilderness area to another.
The philosophy of ___________________strives to enable people to use natural resources in ways that will
benefit them and maintain the ecosystem.
___________________programs release organisms into an area where the species once lived.
An organism that is held by people is said to be in captivity.
By establishing seed banks for threatened and endangered plants, the species can be reintroduced if they
become extinct
• Animals kept in _____________ may lose the necessary behaviors to survive and reproduce in the wild.