Question 1

Why are there no spruces in the early seral stages of succession at Glacier Bay?

Accepted Answer

The answer of Why are there no spruces in the...

Question 2

How do herbivores affect the outcome of succession in intertidal zones?

Accepted Answer

Herbivores in intertidal zones can have a significant effect on the outcome of succession by foraging on particular types of algae. This can allow other species of algae to dominate, which can change the community structure and affect the overall succession of the ecosystem.

Question 3

One of the traits common in late-succession plant species is

Accepted Answer

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Question 4

Jaccard's index quantifies

Accepted Answer

Jaccard's index is calculated by dividing the number of shared species between two communities by the number of unique species across both communities. Therefore, it quantifies the similarity between communities.

Question 5

(Figure 19.11) Given the results in the figure, what might prevent a tree with large seeds, like a chestnut, from establishing in a forest with high densities of sweet birch seeds, an early-succession species?

Accepted Answer

The results in the figure show that sweet birch seeds germinate and grow faster than other tree species in the same area. This means that if a forest has high densities of sweet birch seeds, these seedlings will establish and grow faster than other tree species, including chestnut, which has large seeds. As a result, sweet birch seedlings will often crowd out other tree species, including chestnut saplings, making it difficult for the chestnut to establish in the area.

Question 6

What characteristic shared by diatoms and cyanobacteria might make them good colonizers of nutrient-poor habitats?

Accepted Answer

Diatoms and cyanobacteria both possess the ability to photosynthesize and produce carbohydrates from light energy. This makes them well adapted to colonizing nutrient-poor habitats where other organisms may struggle to survive due to the lack of available nutrients.

Question 7

Typical colonizers in primary succession are mosses and lichens that inhabit bare rock. What colonizers in primary succession do not inhabit bare rock?

Accepted Answer

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Question 8

What information about species is needed to calculate Jaccard's index?

Accepted Answer

Jaccard's index compares the similarity of two sets of species based on the number of species that are shared between them. Therefore, the information needed to calculate Jaccard's index includes only the species present in each set, not their diversity, growth rate or mortality.

Question 9

Topic succession in terrestrial environments
Level: medium
The assumptions behind the valid use of chronosequences are usually not all met. How, then, do researchers establish the most likely scenario of terrestrial succession in a given area?

Accepted Answer

The answer of Topic succession in terrestrial environments
Level: medium
The assumptions...

Question 10

Why do plants in early seral stages exhibit high levels of tolerance?

Accepted Answer

Plants in early seral stages must often deal with harsh environmental conditions, including fluctuating temperatures, intense sun exposure, and nutrient-poor soil. In order to survive and establish themselves in these challenging conditions, early plants typically exhibit high levels of tolerance to stress. This can include the ability to withstand extreme temperatures, adapt to changing soil conditions, and resist insect or disease damage. In contrast, later successional plants may be more specialized and less adaptable, as they have evolved in response to stable environmental conditions over time.

Question 11

Early-succession species are likely to have

Accepted Answer

Early-succession species often colonize open, disturbed areas where there is little competition for resources. Wind-dispersed seeds allow these species to colonize new areas quickly and efficiently, without relying on animals or other dispersal mechanisms. High shade tolerance, short seed viability, and large size at maturity are more characteristic of late-succession species, which often occur in dense, mature forests where competition for resources is high.

Question 12

What are the characteristics of plants found immediately after a drought in a pond?

Accepted Answer

Plants found immediately after a drought in a pond have low root-to-shoot ratios because they allocate more resources to above-ground growth to compete for limited resources while water is scarce. This allows them to quickly establish themselves and reproduce before resources become scarce again. They may also have smaller seeds that are better adapted to surviving in dry soil. They are not necessarily larger or have high tolerance to shade, and their growth rates may be increased as they rebound from the drought.

Question 13

Which of the following is NOT a trait of a pioneer species?

Accepted Answer

Pioneer species are typically characterized by traits that allow them to quickly establish in disturbed or newly created environments. These traits include producing many small seeds, being fast-growing, and having the ability to tolerate harsh conditions such as full sunlight or drought. However, pioneer species are typically not shade tolerant, as they are adapted to quickly colonize open areas with plenty of available light.

Question 14

Describe the process that forms bogs in lakes.

Accepted Answer

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Question 15

Which of the following is TRUE about succession?

Accepted Answer

In both aquatic and terrestrial succession, species richness typically increases initially as new species colonize and establish in the area, leading to greater biodiversity over time.

Question 16

When seeds of early- and late-succession species were raised under low light conditions similar to those found in the understorey of mature forest, researchers found that species with _____ seeds had _____ seedling survivorship in shade.

Accepted Answer

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Question 17

(Figure 19.10) These graphs show that succession is associated with a rapid increase in species richness that slows and levels off over time. How might you explain a graph showing succession with an initial increase in species richness followed by a decline in species richness over time?

Accepted Answer

Inhibition can occur when one species becomes dominant and suppresses the growth of other species in the area, leading to a decline in overall species richness over time.

Question 18

Late-succession species are likely to have

Accepted Answer

Late-succession species tend to have larger seeds, which is a strategy that allows their seedlings to establish in the competitive environment of a mature ecosystem. These species are typically slower to mature and invest more in each offspring, hence the larger seed size.

Question 19

Why must oxygen concentrations remain at low levels for pond succession to occur?

Accepted Answer

Low oxygen levels decrease decomposition rates, which leads to the accumulation of organic matter, such as peat. This process is essential for pond succession, as it gradually fills in the pond and allows for the establishment of terrestrial plant communities.

Question 20

When considering the effect of one species on the probability of a second species becoming established, facilitation is_____, inhibition is _____, and tolerance is _____.

Accepted Answer

Facilitation has a positive effect on the establishment probability of a second species, inhibition has a negative effect, and tolerance is neutral. Therefore, the best choice is C because it correctly describes the effects of facilitation and inhibition and states that tolerance has no effect.

Quiz 19: Community Succession