37.8-37.12

Question 1

Define “Trophic Structure”

Answer 1

A Trophic Structure is a pattern of feeding relationships on several different levels.

Question 2

Define “food chain”

Answer 2

The process of going up the Trophic Structure.

Question 3

What organism is at the bottom of the food chain?

Answer 3

producers/autotrophs/photosynthesizers. Marine: phytoplankton, terrestrial: plants. Hydrothermal vents: chemosynthetic prokaryotes. (??)

Question 4

What is the first level of the food chain/trophic structure called?

Answer 4

Primary consumers/herbivores. Directly dependent on producers. Terrestrial: grasshoppers, insects, snails, grazing animals, birds. Aquatic: zooplankton

Question 5

What are the higher levels of a food chain?

Answer 5

primary, secondary, tertiary and quaternary consumers. They each eat the lower one.

Question 6

What are examples of secondary consumers?

Answer 6

terrestrial: mice, birds, frogs, spiders. However, lions that eat grazers can be here too! Aquatic: small fishes that eat zooplankton

Question 7

What are examples of tertiary consumers?

Answer 7

Terrestrial: snakes. Aquatic: tuna Most ecosystems have secondary and tertiary consumers.

Question 8

What are example of quaternary consumers?

Answer 8

Terrestrial: Hawk Aquatic: Killer whale. Not super common.

Question 9

Where can you find animals that derive their energy from detritus?

Answer 9

all trophic levels: they all produce waste.

Question 10

What is detritus, and what are some examples?

Answer 10

animal wastes, plant litter, body of dead organisms.

Question 11

What are scavengers?

Answer 11

Crows and vultures: eat carcasses that are usually fresher.

Question 12

What are examples of detritivores, and what do they eat?

Answer 12

Millipedes, earthworms. They usually eat detritus that has been decomposing for longer.

Question 13

What are the role of decomposers in the Trophic levels?

Answer 13

They connect the Trophic levels. As they convert detritus to inorganic materials which plants and phytoplankton can use, they convert it into a cycle.

Question 14

If you eat pizza, what trophic level are you on?

Answer 14

Primary.

Question 15

In 37.8, the Trophic structure is described as linear. What is a more accurate description of a trophic structure?

Answer 15

A food web.

Question 16

Can you be more than more than one level of consumer?

Answer 16

Yes. See example in 37.9.

Question 17

What is species diversity defined by?

Answer 17

Singular species abundance and species richness (diversity)

Question 18

If a certain species is dependent on a certain tree, what would happen in an environment that has high species diversity/richness and abundance that is not that tree?

Answer 18

They would struggle significantly if the woods where they lived had the tree that they needed, but was dominated by a different tree. This would also send waves throughout the food web.

Question 19

How do species diversity and pathogens intersect?

Answer 19

More rich species in environment have less of a consequence because of pathogens, as pathogens often can only affect certain hosts.

Question 20

What is monoculture?

Answer 20

Low species diversity. A characteristic of modern agriculture; fields with only one singular specie. Plants are often bred to have desirable traits; there is little genetic diversity within the singular species. They are especially prone to attacks by pathogens. Caused the Irish potato famine!

Question 21

What was the solution to the pathogens and monoculture issue?

Answer 21

Chemical methods; however they became genetically resistant and continued to infect. This situation caused the Corn Leaf Blight.

Question 22

What are farmers and scientists exploring to replace monoculture?

Answer 22

Polyculture.

Question 23

Would you expect a well-maintained or a poorly-maintained lawn to have more species diversity?

Answer 23

A poorly-maintained lawn would have higher species diversity. Well-maintained would have weeds plucked away, etc.

Question 24

What causes species diversity to vary among different communities? (37.11)

Answer 24

The ability of predators to prevent any one species from monopolizing resources. This interspecific interaction determines species diversity. See Paine Experiment.

Question 25

What is the name for the predator that stops the monopolization and decrease in species diversity?

Answer 25

A keystone species.

Question 26

Removing saguaro cacti from the Sonoran desert community would have a drastic impact, and yet saguaro is not considered a keystone species. Why?

Answer 26

Saguaro is abundant, but its effect is not disproportionate to its biomass or abundance. Keystone species have a large effect relative to their representation in the community just as a keystone is a small but vital piece of the arch.

Question 27

In ecosystems, what are disturbances?

Answer 27

storms, fires, floods, droughts or human activities that damage biological communities and alter the availability of sources. Severity and frequency varies.

Question 28

Can disturbances be positive?

Answer 28

Yes, small-scale one can create new communities.

Question 29

What is ecological succession?

Answer 29

After a major disturbance, how the new ecosystem grows back, often colonized by new species.

Question 30

What is primary succession?

Answer 30

Ecosystems that start from something that is virtually lifeless. No soil, like the melting of a glacier. Usually starts with autotrophic bacteria, then lichen, then plants, then animals. Can take thousands of years.

Question 31

What is secondary succession?

Answer 31

Where there is soil intact, but its resources are depleted, from forest clearing, etc.

Question 32

what species are the most successful in secondary succession.

Answer 32

Those with low survivorship curves.

Question 33

In early stages of (secondary?) succession, what species dominates?

Answer 33

Weeds. Not much interspecific competition in the early years, however.

Question 34

Define perennial

Answer 34

enduring, continually recurring

Question 35

What happens in succession from 5-15 years.

Answer 35

It becomes a pine forest.

Question 36

Post-15 years, what trees begin to replace pines?

Answer 36

As pines need much sun to grow, and seedlings to do not receive it when the canopy becomes denser. Deciduous trees, such as maple and oak, which can survive better in shade, replace.

Question 37

How is the new ecosystem after succession finally determined?

Answer 37

it depends on geography and topography, climate. What is settles as determines the consumers in the area.