Varsha Sewlal- Cyber Attacks on Critical Critical Infrastructure
Population Factors and Dynamics
1.
2. Geographic Distribution: a term that describes the
area inhabited by a population.
Population Density: the number of individuals per
unit area.
Growth Rate: the rate at which a population
increases or decreases and the factors that
influence such rate.
So……what are some of these factors?
3. Birth rate vs. death rates
If birth rate is higher than death rate the population
will increase.
If death rate is higher than birth rate the population
will decrease.
Immigration
The movement of individuals into an area. Many of
our parents are immigrants from another country.
4. Emigration
The movement of individuals out of an area. Many of
our parents emigrated when they left their country.
Limiting Factors
A factor that causes population growth to decrease.
Like what you ask………..here are some examples:
5. Competition: when a population becomes too
crowded and they have to compete for things like
food, water, space, sunlight, etc.
Predation: control of a population through
predator/prey relationships.
Parasitism and disease: control of a population
through exposure to parasites and diseases.
These 3 factors are called “Density-dependent
limiting factors”
The next 2 are known as “Density-independent
limiting factors”
6. Climate Extremes: drought, snowstorms,
hurricanes, excess rain, etc. It’s when mother
nature does her part to help control a population.
Human Disturbances: building a dam, tearing down
forests, expansion of human populated areas, etc.
When we build something new, some animals may
have lost their homes or even their lives.
How do people affect these factors?
7. When we build something new
(schools, roads, shopping centers, etc.) we can
create a big impact on the environment.
Protected wildlife
The Florida Everglades
Illegal dumping of chemicals by major companies
Our laws don’t always do the best job
protecting our environment.
8. The largest number of individuals that a given
environment can support is a carrying capacity. In
other words……the most amount that a place can
hold without creating any problems.
Would like to be in an overcrowded elevator?
Hhhhmmmmm?
9. What are some negative outcomes of reaching
carrying capacity?
Insufficient space (population explosion)
Insufficient food (predator/prey fluctuations)
Insufficient sunlight
Forced to relocate
10. 1. An unusually warm spring leads to an increase in the
number of mice in a fertile valley. One result of this
population explosion is the loss of farmers' crops due to
consumption by the mice. What would be another likely result
of the population increase of the mice?
A. Mice will fill a different niche in the ecosystem.
B. The following year the spring will be warm again.
C. Birds of prey that eat mice will become more numerous.
D. Animals that compete with mice will adapt to find new
niches.
11. 2. As the human population rises, the demand for popular fish,
like tuna, in grocery stores and restaurants has also gone up.
Many people enjoy eating these types of fish. How might
increasing the number of tuna
caught affect the tuna fishery over the long term?
A. The tuna population may decrease, but then rebound after
the tuna adapt.
B. The tuna population as a whole may decrease, but the
demand for tuna will also decrease.
C. The tuna population may decrease; therefore, fishing
restrictions will need to be implemented.
D. The tuna population as a whole may decrease, but
individuals may be larger due to less competition.
12. 3. Why does a nonspecialized animal population have a much
better chance of surviving a major disturbance in their
habitat than a very specialized population?
A. It can more easily adapt to different conditions.
B. It can reproduce at a faster rate.
C. It can hibernate through a time of crisis.
D. It can mutate faster than a specialized population.
Lets try a few more since you’re doing sssooooooooo well.
13. 4. In 1533, Mr. Ledesma released goats to graze on the grasses
on the island of St. Helena's in the South Atlantic in order to
serve as a food source for sailors on passing ships. A few
years later goats were plentiful, but many of the native
plants and animals no longer inhabited the island. Which of
the following is the most likely cause for the disappearance
of the plants and animals?
A. The goats fed on the other plants and animals.
B. The goats had no natural predators on the island, so they
reproduced rapidly and overgrazed.
C. The goats brought diseases to the island that killed the native
plants and animals.
D. Sailors more frequently visited the island for food and
destroyed the vegetation.
14. 5. A population of rabbits experiences a large increase over
time. Ms. Donohue claims that this is because the number of
gardens near the woods has increased. Which statement is a
valid alternative explanation for the population increase?
A. Another species of rabbit has been introduced into the area.
B. The population has reached the carrying capacity of the area.
C. A conservation group has released a mated pair of hawks in
the area.
D. The passage of a leash law has kept predatory dogs from
roaming freely.
Well…………….maybe just one more.
15. 6. Northern Harrier Hawks, also known as Marsh Hawks, get
their name from their hunting method of flying low over the
surface of fields in measured patterns, then pouncing upon
rodents, frogs, lizards, and snakes. The graph shows a
general relationship between these types of predators and
their prey in an ecosystem.
Which choice is true when analyzing
predator and prey population sizes?
A. Predator populations increase
shortly after prey populations increase.
B. A decrease in prey populations causes
predator populations to increase.
C. An increase in prey populations causes a drastic decrease in
predator populations.
D. Prey populations increase at exactly the same time that
predator populations increase.
