Ecology B/C

Test your knowledge of various Science Olympiad events.
tm-scioli
Member
Member
Posts: 66
Joined: September 30th, 2015, 4:07 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by tm-scioli » October 25th, 2016, 7:13 pm

An analysis of 2 areas (one on the north side of a ridge and the other on the south) in a chaparral biome yield the following breakdown of area coverage:
North Slope: Coast live oak (27%), Toyon (38%), coastal wood fern (15%), and Laurel sumac (20%)
South Slope: Black sage (67%), California buckwheat (13%), ripgut brome (10%), and Laurel sumac (10%)
[list=1]
[*]Given that the north slope receive an average of 20in of rain per year and that the south slope recieves only 8in, outline a possible reason for the difference and similarities in plant coverage between the two areas
[*]A fire sweeps through both sites, and they are reevaluated 10 years later.  The study finds 30%, 40%, 2%, and 0% respectively for the north slope plants with 28% of a new invasive annual grass that dries out in early spring.  Given that toyon and laurel sumac are chaparral shrubs, explain the significance of the change in coverage of the two species after the fire
[*]Predict what may happen in the long term on the north slope plot[/list]

User avatar
Zioly
Member
Member
Posts: 152
Joined: April 17th, 2016, 4:50 pm
Division: B
State: WA
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by Zioly » October 28th, 2016, 4:58 pm

tm-scioli wrote:
An analysis of 2 areas (one on the north side of a ridge and the other on the south) in a chaparral biome yield the following breakdown of area coverage:
North Slope: Coast live oak (27%), Toyon (38%), coastal wood fern (15%), and Laurel sumac (20%)
South Slope: Black sage (67%), California buckwheat (13%), ripgut brome (10%), and Laurel sumac (10%)
[list=1]
[*]Given that the north slope receive an average of 20in of rain per year and that the south slope recieves only 8in, outline a possible reason for the difference and similarities in plant coverage between the two areas
[*]A fire sweeps through both sites, and they are reevaluated 10 years later.  The study finds 30%, 40%, 2%, and 0% respectively for the north slope plants with 28% of a new invasive annual grass that dries out in early spring.  Given that toyon and laurel sumac are chaparral shrubs, explain the significance of the change in coverage of the two species after the fire
[*]Predict what may happen in the long term on the north slope plot[/list]
1. Are the slope's precipitations flipped? As in, shouldn't the north have 8in and the south have 20in? I say this as the south side more represents the cismontane chapparal, which is always the coastal side of a ridge, which entails more precipitation, and the north side more represents the transmontane chapparal, which, of course, should receive less precipitation, as it's on the non-coastal side of the ridge, so much of the rainfall is emptied into the cismontane side, leaving the transmontane side with little to none. This is described as a rain shadow. The difference in precipitation is key to the plant coverage. Transmontane plants are much more drought-adapted, and can survive in desert-like climates, while cismontane plants aren't as much, and are forced to grow on the coastal cismontane side.
2. The fire burnt the scrubs on the surface, but didn't touch the larger plants, which would explain why the coast live oak population did not decrease. The toyon population also did not dwindle, as they've already resprouted. The toyon have adapted so that after a fire, their deep roots, aka the burl, resprouts a new plant and their population barely changes. As the span between the fire and the data is 10 years, it's not surprising that the toyon have reestablished. However, the laurel sumac takes at least 50 years to resprout, which is why the population is next to none, although the the coastal wood fern sprouts slightly faster, as it's just now starting to, at 2%. Either that, or the survivors of coastal wood ferns contribute to the 2% and are soon to reproduce; I didn't find much info on it. Finally, when referring to the new grass plant, these plants are what are called fire followers or fire annuals, in which the seeds are buried beneath the shade of other chaparral plants. When a fire burns through the brush, the sunlight can reach these fire followers and they sprout.
3. In ~50-70 years, the majority of laurel sumac will resprout, which will then recreate the signature thick brush of the chapparal, blocking the sunlight, and preventing the invasive grasses from regrowing. Now, the biome is back to it's pre-fire state, but with more fuel for the next fire, as the burnt biomass of the previous fire can serve as more fuel.

Very great question, by the way.
Edit: Fixed it not hiding the text.
Bottle Rockets: 5th
Ecology: 9th
Hovercraft: 14th
Scrambler: 29th (with a failed run too  ;))
Mousetrap Vehicle
Hovercraft
Ecology
Experimental Design (or other inquiry :P)

...Yes, my profile picture is G2 apEX at the PGL Major Qual.  :lol:

tm-scioli
Member
Member
Posts: 66
Joined: September 30th, 2015, 4:07 pm
Division: C
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by tm-scioli » October 30th, 2016, 9:26 am

1. yes, it is generally true that south facing slopes receive somewhat greater precipitation, but this is heavily outweighed in many lower and warmer chaparrals by the fact that the north slope chaparrals receive less direct sunlight and therefore have greater soil moisture than south facing slopes (note: in chaparrals on very high coastal ranges, the difference in rainfall is often great enough to make the south slope the moister of the two).  I just wrote it that way for simplicity.  Other than that, your answer is generally correct (drought resistant plants on drier side and less tolerant but larger plants on wetter side), but I was mainly looking for you to mention that laurel sumac is able to thrive in both areas because it is able to tap into water deep underground.
2. yeah, pretty much, but make sure that you recognize that fire followers in chaparral biomes are mostly herbaceous flowering annuals or short lived perennial shrubs.  Annual grasses are typically invasive and are disturbance selected not solely fire followers like some chaparral plants.  Most fire followers would be gone by 10 years after a fire.  Also, deep roots is somewhat different from having a burl.  Laurel sumac has deep roots and can survive in a wide range of precipitation zones because of them whereas toyon has a burl which is somewhat similar to a root crown or tuber just below the soil surface where it stores energy necessary to resprout.

User avatar
Zioly
Member
Member
Posts: 152
Joined: April 17th, 2016, 4:50 pm
Division: B
State: WA
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by Zioly » October 30th, 2016, 6:15 pm

tm-scioli wrote:
1. yes, it is generally true that south facing slopes receive somewhat greater precipitation, but this is heavily outweighed in many lower and warmer chaparrals by the fact that the north slope chaparrals receive less direct sunlight and therefore have greater soil moisture than south facing slopes (note: in chaparrals on very high coastal ranges, the difference in rainfall is often great enough to make the south slope the moister of the two).  I just wrote it that way for simplicity.  Other than that, your answer is generally correct (drought resistant plants on drier side and less tolerant but larger plants on wetter side), but I was mainly looking for you to mention that laurel sumac is able to thrive in both areas because it is able to tap into water deep underground.
2. yeah, pretty much, but make sure that you recognize that fire followers in chaparral biomes are mostly herbaceous flowering annuals or short lived perennial shrubs.  Annual grasses are typically invasive and are disturbance selected not solely fire followers like some chaparral plants.  Most fire followers would be gone by 10 years after a fire.  Also, deep roots is somewhat different from having a burl.  Laurel sumac has deep roots and can survive in a wide range of precipitation zones because of them whereas toyon has a burl which is somewhat similar to a root crown or tuber just below the soil surface where it stores energy necessary to resprout.
Gotcha! New question:

Scientists have discovered fossils of 3 ancient reptilian animal species, and have been able to determine the following about their dates:

Of species A, scientists have found abundant fossils of it from 300 A.D. all the way to 1000 A.D.
Of species B, scientists have found abundant fossils of it from 300 A.D. all the way to 400 A.D.
Of species C, scientists have found abundant fossils of it from 450 A.D. all the way to 1000 A.D.

Scientists have noted that species A and B are very similar, both feeding on the same organisms and living in the same habitats, while species C is completely different from A and bears a slight resemblance to species B.

Additionally, from 1000 A.D. to the present day, the earth is dominated by mammalian species, and the majority of the reptilian species was wiped out.*

1. What happened with the three species in the years 350-450 A.D., roughly?
2. What does the previous scientific observation* describe?
3. What was happening in the few hundred years prior to the event described in question two?

Notes:
-Dates aren't actually real, by the way, but the concept still applies. These dates and time frames are completely exaggerated, as the real processes would take millions of years.
-I may give hints, if necessary.
-Questions two and three assume that the press-pulse theory of Arens and West is true.
-Species A and B cannot interbreed.
Bottle Rockets: 5th
Ecology: 9th
Hovercraft: 14th
Scrambler: 29th (with a failed run too  ;))
Mousetrap Vehicle
Hovercraft
Ecology
Experimental Design (or other inquiry :P)

...Yes, my profile picture is G2 apEX at the PGL Major Qual.  :lol:

User avatar
dcrxcode
Exalted Member
Exalted Member
Posts: 129
Joined: March 22nd, 2015, 8:53 am
Division: Grad
State: IN
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by dcrxcode » November 19th, 2016, 6:39 pm

Zioly wrote:
Gotcha! New question:

Scientists have discovered fossils of 3 ancient reptilian animal species, and have been able to determine the following about their dates:

Of species A, scientists have found abundant fossils of it from 300 A.D. all the way to 1000 A.D.
Of species B, scientists have found abundant fossils of it from 300 A.D. all the way to 400 A.D.
Of species C, scientists have found abundant fossils of it from 450 A.D. all the way to 1000 A.D.

Scientists have noted that species A and B are very similar, both feeding on the same organisms and living in the same habitats, while species C is completely different from A and bears a slight resemblance to species B.

Additionally, from 1000 A.D. to the present day, the earth is dominated by mammalian species, and the majority of the reptilian species was wiped out.*

1. What happened with the three species in the years 350-450 A.D., roughly?
2. What does the previous scientific observation* describe?
3. What was happening in the few hundred years prior to the event described in question two?

Notes:
-Dates aren't actually real, by the way, but the concept still applies. These dates and time frames are completely exaggerated, as the real processes would take millions of years.
-I may give hints, if necessary.
-Questions two and three assume that the press-pulse theory of Arens and West is true.
-Species A and B cannot interbreed.
Hmm how can A be very similar to B but C isn't similar to A but IS similar to B?
1. A and B had the same common ancestor, but C evolved from B in 350-450 AD. Species B went extinct/evolved into C between 350 and 450 AD.
2. I think you're looking for a pulse event? I would have said "evolution" if you didn't discuss Arens/West.
3. Press events -- volcanism, climate change etc.
Edit: for whatever reason the hide code isn't working for me [hide]hide this[/hide]

User avatar
Zioly
Member
Member
Posts: 152
Joined: April 17th, 2016, 4:50 pm
Division: B
State: WA
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by Zioly » November 19th, 2016, 7:08 pm

dcrxcode wrote:
Zioly wrote:
Gotcha! New question:

Scientists have discovered fossils of 3 ancient reptilian animal species, and have been able to determine the following about their dates:

Of species A, scientists have found abundant fossils of it from 300 A.D. all the way to 1000 A.D.
Of species B, scientists have found abundant fossils of it from 300 A.D. all the way to 400 A.D.
Of species C, scientists have found abundant fossils of it from 450 A.D. all the way to 1000 A.D.

Scientists have noted that species A and B are very similar, both feeding on the same organisms and living in the same habitats, while species C is completely different from A and bears a slight resemblance to species B.

Additionally, from 1000 A.D. to the present day, the earth is dominated by mammalian species, and the majority of the reptilian species was wiped out.*

1. What happened with the three species in the years 350-450 A.D., roughly?
2. What does the previous scientific observation* describe?
3. What was happening in the few hundred years prior to the event described in question two?

Notes:
-Dates aren't actually real, by the way, but the concept still applies. These dates and time frames are completely exaggerated, as the real processes would take millions of years.
-I may give hints, if necessary.
-Questions two and three assume that the press-pulse theory of Arens and West is true.
-Species A and B cannot interbreed.
Hmm how can A be very similar to B but C isn't similar to A but IS similar to B?
1. A and B had the same common ancestor, but C evolved from B in 350-450 AD. Species B went extinct/evolved into C between 350 and 450 AD.
2. I think you're looking for a pulse event? I would have said "evolution" if you didn't discuss Arens/West.
3. Press events -- volcanism, climate change etc.
Edit: for whatever reason the hide code isn't working for me [hide]hide this[/hide]
Nice! All correct and exactly what I was looking for! Any tips on how I should write these long questions in the future? Meaning, I won't write long questions every time, but when I do, I want them to be good questions.

User avatar
dcrxcode
Exalted Member
Exalted Member
Posts: 129
Joined: March 22nd, 2015, 8:53 am
Division: Grad
State: IN
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by dcrxcode » November 19th, 2016, 9:43 pm

Zioly wrote: Nice! All correct and exactly what I was looking for! Any tips on how I should write these long questions in the future? Meaning, I won't write long questions every time, but when I do, I want them to be good questions.
I liked the ideas the question was going after, as well as the length and complexity. Perhaps real dates would have helped as setting it in AD with >1000 AD dominated by mammals kinda contradicts the fossil record. Just a thought on that.

Mentioning the Arens/West paper helped me learn because I had to look the paper up (link: https://www.researchgate.net/publicatio ... extinction) and learn about the Press-Pulse concepts. Without mentioning that, I'd definitely have gotten the whole problem wrong. Review some of the wording for vagueness next time - lots of different intepretations for question 1.

Whose study (1) of what species (1) formed the idea of realized niche width? Explain the study (3) and show how it demonstrates realized niche width (2).

Points in parentheses.

User avatar
Zioly
Member
Member
Posts: 152
Joined: April 17th, 2016, 4:50 pm
Division: B
State: WA
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by Zioly » November 20th, 2016, 12:03 pm

dcrxcode wrote:
Zioly wrote: Nice! All correct and exactly what I was looking for! Any tips on how I should write these long questions in the future? Meaning, I won't write long questions every time, but when I do, I want them to be good questions.
I liked the ideas the question was going after, as well as the length and complexity. Perhaps real dates would have helped as setting it in AD with >1000 AD dominated by mammals kinda contradicts the fossil record. Just a thought on that.

Mentioning the Arens/West paper helped me learn because I had to look the paper up (link: https://www.researchgate.net/publicatio ... extinction) and learn about the Press-Pulse concepts. Without mentioning that, I'd definitely have gotten the whole problem wrong. Review some of the wording for vagueness next time - lots of different intepretations for question 1.

Whose study (1) of what species (1) formed the idea of realized niche width? Explain the study (3) and show how it demonstrates realized niche width (2).

Points in parentheses.
Realized niche width is the range to which a specie's niche actually reaches, compared to a niche width, a usually wider range that describes the potential niche of a species, that is, what it could do with unlimited resources and no predators.

Case 1

Joseph Connell's study of intertidal barnacles, specifically the Chthamalus stellatus and Balanus balanoides, found that the barnacles shared different parts of the intertidal strata, the former taking the upper and the ladder taking the lower. Connell found that Chthamalus stellatus, in fact, could survive in both stratas, however, the presence of the other species prevented it from achieving its potential niche, therefore only reaching the realized niche of the upper strata. This was the first documented study of interspecific competition and proves the idea of realized niche width, that is a realized niche is specifically determined by limiting factors, such as interspecific competition in this case.

Case 2

A possibly more famous study conducted by Robert MacArthur on warblers of the North American spruce forests found that a total of 5 species of warblers could live in one tree. Competitive exclusion or Gause's Law theorized that if two species shared the same resources, one would eventually go extinct, let alone 5. MacArthur found that the 5 warbler species all lived in different parts of the tree, and thus partitioned resources so they could all live together. This also documents a realized niche as effectively, one species of warblers, without the presence of the other 4, could easily thrive on the rest of the tree parts.
Last edited by Zioly on November 21st, 2016, 4:00 pm, edited 2 times in total.

User avatar
dcrxcode
Exalted Member
Exalted Member
Posts: 129
Joined: March 22nd, 2015, 8:53 am
Division: Grad
State: IN
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by dcrxcode » November 20th, 2016, 12:35 pm

Zioly wrote:
dcrxcode wrote:
Whose study (1) of what species (1) formed the idea of realized niche width? Explain the study (3) and show how it demonstrates realized niche width (2).

Points in parentheses.
Realized niche width is the range to which a specie's niche actually reaches, compared to a niche width, a usually wider range that describes the potential niche of a species, that is, what it could do with unlimited resources and no predators.

Case 1

Joseph Connell's study of intertidal barnacles, specifically the Chthamalus stellatus and Balanus balanoides, found that the barnacles shared different parts of the intertidal strata, the former taking the upper and the ladder taking the lower. Connell found that Chthamalus stellatus, in fact, could survive in both stratas, however, the presence of the other species prevented it from achieving its potential niche, therefore only reaching the realized niche of the upper strata. This was the first documented study of interspecific competition and proves the idea of realized niche width, that is a realized niche is specifically determined by limiting factors, such as interspecific competition in this case.

Case 2

A possibly more famous study conducted by Robert MacArthur on warblers of the North American spruce forests found that a total of 5 species of warblers could live in one tree. Competitive exclusion or Gause's Law theorized that if two species shared the same resources, one would eventually go extinct, let alone 5. MacArthur found that the 5 warbler species all lived in different parts of the tree, and thus partitioned resources so they could all live together. This also documents a realized niche as effectively, one species of warblers, without the presence of the other 4, could easily thrive on the rest of the tree parts.
All correct - I've heard of Connell's study more in the context of realized niche width, but I suppose the other examples works just as well.

Don't forget to hide :D

User avatar
Zioly
Member
Member
Posts: 152
Joined: April 17th, 2016, 4:50 pm
Division: B
State: WA
Has thanked: 0
Been thanked: 0

Re: Ecology B/C

Post by Zioly » November 21st, 2016, 3:56 pm

dcrxcode wrote:
Zioly wrote:
dcrxcode wrote:
Whose study (1) of what species (1) formed the idea of realized niche width? Explain the study (3) and show how it demonstrates realized niche width (2).

Points in parentheses.
Realized niche width is the range to which a specie's niche actually reaches, compared to a niche width, a usually wider range that describes the potential niche of a species, that is, what it could do with unlimited resources and no predators.

Case 1

Joseph Connell's study of intertidal barnacles, specifically the Chthamalus stellatus and Balanus balanoides, found that the barnacles shared different parts of the intertidal strata, the former taking the upper and the ladder taking the lower. Connell found that Chthamalus stellatus, in fact, could survive in both stratas, however, the presence of the other species prevented it from achieving its potential niche, therefore only reaching the realized niche of the upper strata. This was the first documented study of interspecific competition and proves the idea of realized niche width, that is a realized niche is specifically determined by limiting factors, such as interspecific competition in this case.

Case 2

A possibly more famous study conducted by Robert MacArthur on warblers of the North American spruce forests found that a total of 5 species of warblers could live in one tree. Competitive exclusion or Gause's Law theorized that if two species shared the same resources, one would eventually go extinct, let alone 5. MacArthur found that the 5 warbler species all lived in different parts of the tree, and thus partitioned resources so they could all live together. This also documents a realized niche as effectively, one species of warblers, without the presence of the other 4, could easily thrive on the rest of the tree parts.
All correct - I've heard of Connell's study more in the context of realized niche width, but I suppose the other examples works just as well.

Don't forget to hide :D
Went up and fixed the hiding! :D

In a standard tundra biome, a company is drilling oil. It is mid-summer and the top layer of permafrost has melted. Give an example of how this company and its workers could affect the annual group of migratory birds that settle in the biome during the summer.

Locked

Return to “2017 Question Marathons”

Who is online

Users browsing this forum: No registered users and 2 guests