How Changes Occur Naturally in Ecosystems

The Galapagos Islands are inhabited by 13 species of finch that gather and eat different types of food. Why did natural selection result in the development of these 13 distinct species of finches?

Certain characteristics give some finches an advantage over others in a particular niche
Finches decide to change their characteristics to match a particular niche
Natural selection allows only finches with certain characteristics to travel to the Galapagos from the mainland
Some finches were more vulnerable to finch-eating predators

Why are organisms like lichens called “pioneer” species?

Species like these are the first to arrive and successfully survive and reproduce in an area
Lichens always grow towards the west side of rocks, moving like pioneers used to
Once nutrient sources have been established, pioneer species move into an area
Decomposer species like lichens thrive in areas where weak organisms are trying to survive

In primary succession, producers are very important for their ability to capture and pass along solar energy. Where does the soil that plants need to grow in come from?

Lichens and other pioneer species break down rocks into smaller parts, and add to the organic content of the soil as they themselves die and decompose
Wind and gravity push soil particles along until they pile into usable areas for plant growth
After many traveling animal species die and decompose in a barren area, soil begins to form
Sudden events like volcanic eruptions and earthquakes release soil and ash to the surface

10 000 years ago, huge glacial ice sheets that covered most of Canada stopped advancing down from the Arctic. After melting, the glaciers revealed a barren landscape that did not support life for thousands of years.

What process began to occur first after the glaciers retreated and temperatures began to rise?

Primary succession
Secondary succession
Natural selection
Adaptive radiation

The mountain pine beetle, along with blue stain fungi, can attack and destroy huge numbers of pine trees in a forest.

Which of the following is a reason this beetle is now causing so much destruction to BC forests?

The winters are not cold enough to kill beetle larvae, and trees are stressed by overcrowding
The pine beetle has no natural predators in BC
Pine trees can no longer produce a resin that can trap the beetles effectively
Frequent forest fires make pine trees weak and unable to prevent beetle infestations

When does an area have the largest number of species?

During a climax community
During primary succession
During secondary succession
After a natural disaster

Which of the following natural events would most likely not result in secondary succession?

Thunderstorm
Flooding
Tsunami
Drought

Pine trees attempt to stop infestations of the mountain pine beetle by releasing large amounts of sticky resin to trap the beetles. How do the beetles often avoid this sticky resin?

Blue stain fungus, carried in the beetle’s mouth, destroys the tree’s ability to use the resin
The beetles eat the parts of the tree that produce the resin when they first attack the tree
With warmer summers, the resin is not as sticky as it once was, and does not trap the beetles as effectively
Warmer winters do not allow the trees to build up enough resin to protect themselves during summers

What is required for an area to undergo secondary succession?

As long as soil remains, there will be plants, micro-organisms and small animals to begin secondary succession
Dramatic events such as volcanic eruptions or meteor impacts remove all life and allow secondary succession to begin
When seasons change, and new plants and animals appear, secondary succession begins again
When there is a balance between the numbers of predators and prey, secondary succession can begin

What does primary succession look like in other parts of the world?

The process of primary succession is the same in almost every part of the world
Primary succession in the northern hemisphere is like secondary succession in the southern hemisphere, and vice versa
Primary succession occurs differently in every instance it occurs in the world
The type of primary succession that occurs depend son the types of lichen and rocks that are present

How Changes Occur Naturally in Ecosystems - Section 3.1 Quiz