biology unit 4

An insect population feeds almost exclusively on a single species of plant. The carrying capacity of the insect population is dependent primarily on food availability. Recently, a fire destroyed 80% of the plants that the insects feed upon. How many times as large will the carrying capacity be?

.2

A species of reptile lives on several different islands. Some of the islands contain a certain species of mammal, while some do not. On the islands without the mammal, the reptile species has a carrying capacity of 240 individuals per square kilometer. On islands with the mammal, the reptile species has a carrying capacity of 150 individuals per square kilometer. By what percent is the carrying capacity for the reptile species reduced by the presence of the mammal species? Write the correct value on the line.

37.5% --> 240-150= 90 --> 90/240= 37.5%

Describe a climax community. What are a few examples?

A balanced population of clownfish and sea anemones in a coral reef ecosystem

A scientist wants to study primary succession. After which ecological event should she begin her research?

A retreating glacier exposing bare rock

What would cause an increase in the carrying capacity of herbivores in the environment? List all possible ideas.

An increase in the number and variety of plants in the ecosystem Decrease in the number of predators

The European green crab is an invasive species that has recently entered inland waters of Washington. Once established, this crab can disrupt the natural ecosystem by outcompeting native species for food and habitat. A biologist is collecting data from local salt marshes and estuaries to evaluate the impact of the invasive crab on the populations of native organisms that live there. Which experimental design will most efficiently provide accurate, reliable data for evidence?

Count and record observations on the populations of invasive crabs and native organisms in quadrats at a variety of salt marshes and estuaries.

The graph shows the number of individuals of a given species, out of 1,000, that survive to different percentages of that species' maximum life span. According to the graph, which animal experiences the lowest chance of survival immediately following birth?

Crocodile

Explain the difference between density-dependent and density-independent limiting factors.

Density-dependent- Factors that are affected by the number of individuals in a population Density-independent- Factors that are not affected by the number of individuals in a population.

A population of 2,000 deer lived on a plateau. In 1906, all hunting of the deer was banned, natural predators were exterminated, and sheep and cattle, which competed with the deer, were banned from the plateau. The graph shows the deer population in the years following this.

From 1925 to 1930, resource scarcity was the most influential factor on the changing deer population.

Give examples of what would cause and increase, decrease and no change in a population.

Increase: A deadly disease is spreading among predators of the population Decrease: A natural disaster occurs and destroys valuable resources the population needs for survival Stabilize: The birth rate and death rate are the same

Explain Primary and Secondary succession.

Primary- The establishment and development of an ecosystem in an area that was previously uninhabited. Secondary- Reestablishment of an ecosystem in an area where the soil was left intact

What does it mean for an ecosystem to be resistant? Resilient?

Resistant- The ability of an ecosystem to resist change. Resilient- The ability of an ecosystem to recover after a disturbance. The more resilient takes less time to rebound.

What is logistic growth and when does it occur?

S-shaped curve. More realistic, shows limiting resources play a role.

The graph shows the survivorship curves for three species of organisms living in the same environment. Describe the differences in Survivorship for each species. For example: Species A has a greater percentage of its population reach old age.

Species B has a greater percentage of its population reach old age than species C

If a prey species population decreases, what will happen to the species that eats it?

The predator population will also decrease.

A rabbit population is near the carrying capacity of its ecosystem. If the population density of rabbits in an area were to increase, what direct effect would it most likely have?

The rabbits would have greater competition for resources

What is exponential growth and when does it occur?

When conditions are ideal, population size increases dramatically.