Lab Exam 2: Lab 8

Question 1

What is linear growth?

Answer 1

A fixed number of cells reproduce in each generation

Question 2

What is an example of linear growth?

Answer 2

A corn seed

Question 3

What is the active cell division of a corn seed called?

Answer 3

Apical meristem

Question 4

How do corn seeds represent linear growth?

Answer 4

When they divide, four new cells are created; two of them mature and two remain relatively immature and are ready to divide again

Question 5

What is the equation for linear growth?

Answer 5

N = ct + No
N (population size)
c (rate of increase)
t (time; in generations)
No (initial population size)

Question 6

What is the growth rate on a linear growth plot?

Answer 6

The slope (rate of increase) which are constant

Question 7

What is unrestricted exponential growth?

Answer 7

A fixed proportion of cells reproduce

Question 8

What is the equation of unrestricted exponential growth?

Answer 8

N = Noe^(rt)
N (population size)
No (initial population size)
e (Euler’s number)
r (intrinsic rate of increase)
t (time; in generations)

Question 9

What is the growth rate on the unrestricted exponential growth plot?

Answer 9

The slope (rate of increase) which are NOT constant beware are proportional to population size; as population growths, growth rate increases

Question 10

What is logistic growth?

Answer 10

A type of exponential growth that occurs in environments where various factors restrict growth

Question 11

What is the lag phase of logistic growth?

Answer 11

The number of births is greater than the number of deaths, but the growth is slow because of the small number of individuals in the population

Question 12

What is the log phase of logistic growth?

Answer 12

The organisms are reproducing, and there are many of them reproducing, thus accelerating growth

Question 13

What is the result of the log phase of logistic growth?

Answer 13

Eventually, food becomes scarce, room runs out, and pollution rises which tend to increase the death rate and lower the birth rate and population growth slows

Question 14

What is the stationary phase of logistic growth?

Answer 14

The population size does not change because the birth and death rates are equal

Question 15

What is carrying capacity?

Answer 15

The number of individuals in a population that an environment can support indefinitely

Question 16

What variable represents carrying capacity?

Answer 16

K

Question 17

What are examples limit population growth?

Answer 17

Resources and space limitation

Question 18

What is the equation for logistic growth?

Answer 18

dN/dt = rN ((K-N)/K)

Question 19

If N«K, what does that mean for logistic growth?

Answer 19

= rN

Question 20

If N is approaching K, what does that mean for logistic growth?

Answer 20

Approaching zero

Question 21

If N=K, what does that mean for logistic growth?

Answer 21

No growth (=0)

Question 22

If N>K, what does that mean for logistic growth?

Answer 22

Negative growth

Question 23

How does the intrinsic rate of increase (r) affect the rate of growth?

Answer 23

When the intrinsic rate of increase is larger, it results in a faster rate of growth; a population will reach carrying capacity quicker

Question 24

How does “r” affect carrying capacity?

Answer 24

It does not

Question 25

How does the initial population size affect the time required to reach carrying capacity?

Answer 25

If the initial population size is larger then it will reach carrying capacity quicker

Question 26

How does the initial population size affect the carrying capacity?

Answer 26

It does not

Question 27

What happens when the population size initially exceeds the carrying capacity?

Answer 27

It will decrease until it reaches carrying capacity

Question 28

What does the first overshoot (oscillation) of the population around the carrying capacity mean, in terms of of effect of time to maturity?

Answer 28

As the time to mature increases, the oscillation of the population around the carrying capacity increases because at first, more people are being born and also require less energy which is why there is the first overshoot above the carrying capacity

Question 29

Why does the first overshoot (oscillation) decrease after some time?

Answer 29

Because the population exceeds carrying capacity, the environment cannot sustain the young members who grow older and require more energy so the population decreases (older members die off) and go back down below carrying capacity

Question 30

After the decrease from the overshoot (oscillation), how does the cycle start over again?

Answer 30

Once the decrease occurs, the environment then can replenish its resources which allows again for any overshoot and they cycle repeats

Question 31

Explains the relationship between the single resource and carrying capacity?

Answer 31

At lower levels of the resource, it is a limiting factor because it directly influences the carrying capacity. However, at higher levels it not longer influences carrying capacity because the population stops growing and stays constant regardless of the increase of the resource

Question 32

Explain the relationship between a single harmful factor and carrying capacity.

Answer 32

At low levels of the resource, it does not influence carrying capacity but at high levels it limits the carrying capacity

Question 33

What is an example of a resource that would limit carrying capacity?

Answer 33

Toxins and pollutants

Question 34

Given a chart of resources and the change it has on carrying capacity, how can tell which of the resources is the limiting factor?

Answer 34

The limiting factor is the one that when it increases, so does the carrying capacity. For the other factors, changing the amounts of it does not truly change the carrying capacity

Question 35

What is a niche of an organism?

Answer 35

The range of resources an organism can use

Question 36

Paramecium caudate is an aquatic single called protist, what is one factor that determines its niche?

Answer 36

The amount of oxygen dissolved in the water that surrounds it

Question 37

Why does competition occur?

Answer 37

When niches overlap as two or more organism attempt to simultaneously use the same limited resource

Question 38

Why is it important to first determine the carrying capacity for each population when their niches do no overlap?

Answer 38

It gives reference to when populations are isolated from one another and what their sizes are like when they use different resources

Question 39

How can you tell which population is the more efficient competitor?

Answer 39

The population that remains steady even as the degree of overlap increases while the other population continues to decrease until it gets wiped out

Question 40

Explain why the “losers” might persist when the level of overlap is not large enough for them to die off.

Answer 40

There are still some resources available to the small population of “losers” so they will still continue to fight for them, yet as soon as the level of overlap is large enough, they can no longer compete with the “winners” and will die off

Question 41

How does E. coli benefit humans?

Answer 41

They produce Vitamin K, a substance used by the liver to make blood clotting factors

Question 42

What is one side effect of taking antibiotics?

Answer 42

Not only do they kill the harmful bacteria but they also might kill some of the resident bacteria that we need

Question 43

Even though the antibiotic has a negative impact on the carrying capacity of C. difficile, why is it doing so well under these conditions?

Answer 43

E. coli is much more negatively affected by the antibiotic so as it dies off, there are more resources available for C. difficile to thrive on

Question 44

In the absence of antibiotics, how is E. coli helping its host (other than making Vitamin K)

Answer 44

Limits the amount of C. difficile (a harmful pathogenic)

Question 45

By looking at a graph, how can determine which is the predator? The prey?

Answer 45

The predator has a smaller population size while the prey will have a larger one

Question 46

Explain the oscillation for the predator population.

Answer 46

Increase in population is due to increase in prey population so more food. Decrease in population because prey start become more scarce so harder to find food. Cycle starts again.

Question 47

Explain the oscillation in the prey population.

Answer 47

Increase in population is due to absence in predator. Decrease is due to more predator hunting the abundance of prey. Cycle starts again.

Question 48

Differentiate between linear, unrestricted exponential, and logistic growth.

Answer 48

Linear = growth rate is constant and independent of population size
Unrestricted exponential = growth rate is proportional to population size
Logistic = growth rate is influenced by the difference between carrying capacity and population size

Question 49

Compare the birth rate and death rate during the lag, log, and stationary phases of logistic growth.

Answer 49

Lag = birth rate exceeds death rate, but since population is small growth is slow
Log = birth rate exceeds death rate, the population is large, so growth is rapid
Stationary = birth rate equals death rate, no growth