Biology 181 Exam 4
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1. what does N vs t look like on an exponential growth model: as abundance increases
over time, it curves upward with no end, and the slope is Nt=No(e^rt)
2. when does r change with exponential growth model: as birth decreases and death
increases and vice versa
3. What is the general growth model: N/t=rN, r(per-capita rate of change)=b-d
4. What is the exponential growth model: N/t=rN, where r is a constant
5. what does N/t vs N look like on an exponential growth model: it's a direct relationship
and the slope=r
6. what does r vs N look like on an exponential growth model: it's a straight line
7. what happens to population if r is positive: population increases (birth increases and death
decreases)
8. what happens to population if r is negative: population decreases (birth decreases and death
increases)
9. what happens to population if r is 0: population stays the same
10. What is the logistic growth model: N/t=rN, where r=rmax(1-N/k)
- so N/t=rmaxN(1-N/k)
11. What happens to the population when N=k: the population stops growing
12. what does N vs t look like on the logistic growth model: it curves upward until reaches
the carrying capacity
-the inflection point is where N=1/2k
13. what does N/t vs N look like on the logistic growth model: its a bubble where the top
is where N=1/2k and the x-intercept is where N=k
1/7
, Biology 181 Exam 4
Study online at https://quizlet.com/_hvwnnx
14. What does r vs N look like on the logistic growth model: its an indirect relationship
where x-intercept is where N=k
15. Carrying capacity drawbacks: 1) it does not remain constant-- it can change year to year
2) it takes time for reproductive decline and birth and death rate changes once carrying capacity is reached
16. density-dependent population regulation: Birth and death rates vary as a function of popula-
tion sizes. Intraspecifc competition for resources causes a carrying capacity.
17. density-independent population regulation: resources fluctuate regardless of population
size/abundance
18. how do you calculate per-capita rate of increase (r) from a lifetable: r=(lnRo)/(sum
of xLxMx/sum of LxMx)
19. what is generation time: average amount of time between the birth of an individual and the birth of
its offspring. (sum of xLxMx/Ro)
20. Community: a collection of species found at a certain place and at a certain time
21. Interspecific species interaction: Interacitons between species
22. Mutualistic Interactions: when both species benefit
23. Commonsalisms: when on species benefits and the other is unaffected
24. amensalism: when one species is harmed and the other is unaffected
25. Exploitative Interactions: when one species benefits and the other is harmed
26. Niche: sum of habitat requirements and functional roles of a species
27. direct competition: ability to acquire and defend exclusive use of resources (territory, food, etc)
28. indirect competition: ability to use a scarce resource more effectively than the competitor (the other
species cannot even detect the resource whilst the "winner" is using it up)
29. Competitive Exclusion Principle: Ecological rule that states that no two species can occupy the same
exact niche in the same habitat at the same time, they would die!
30. Conditions of Coexistence: 1) divide space/ different habitat
2) have different competitive strengths (limited by different factors)
3) evolve to avoid competition (Niche overlap over long periods of time)
31. Fundamental Niche: The full potential range of the physical, chemical, and biological factors a species
can use if there is no competition from other species.
2/7
Study online at https://quizlet.com/_hvwnnx
1. what does N vs t look like on an exponential growth model: as abundance increases
over time, it curves upward with no end, and the slope is Nt=No(e^rt)
2. when does r change with exponential growth model: as birth decreases and death
increases and vice versa
3. What is the general growth model: N/t=rN, r(per-capita rate of change)=b-d
4. What is the exponential growth model: N/t=rN, where r is a constant
5. what does N/t vs N look like on an exponential growth model: it's a direct relationship
and the slope=r
6. what does r vs N look like on an exponential growth model: it's a straight line
7. what happens to population if r is positive: population increases (birth increases and death
decreases)
8. what happens to population if r is negative: population decreases (birth decreases and death
increases)
9. what happens to population if r is 0: population stays the same
10. What is the logistic growth model: N/t=rN, where r=rmax(1-N/k)
- so N/t=rmaxN(1-N/k)
11. What happens to the population when N=k: the population stops growing
12. what does N vs t look like on the logistic growth model: it curves upward until reaches
the carrying capacity
-the inflection point is where N=1/2k
13. what does N/t vs N look like on the logistic growth model: its a bubble where the top
is where N=1/2k and the x-intercept is where N=k
1/7
, Biology 181 Exam 4
Study online at https://quizlet.com/_hvwnnx
14. What does r vs N look like on the logistic growth model: its an indirect relationship
where x-intercept is where N=k
15. Carrying capacity drawbacks: 1) it does not remain constant-- it can change year to year
2) it takes time for reproductive decline and birth and death rate changes once carrying capacity is reached
16. density-dependent population regulation: Birth and death rates vary as a function of popula-
tion sizes. Intraspecifc competition for resources causes a carrying capacity.
17. density-independent population regulation: resources fluctuate regardless of population
size/abundance
18. how do you calculate per-capita rate of increase (r) from a lifetable: r=(lnRo)/(sum
of xLxMx/sum of LxMx)
19. what is generation time: average amount of time between the birth of an individual and the birth of
its offspring. (sum of xLxMx/Ro)
20. Community: a collection of species found at a certain place and at a certain time
21. Interspecific species interaction: Interacitons between species
22. Mutualistic Interactions: when both species benefit
23. Commonsalisms: when on species benefits and the other is unaffected
24. amensalism: when one species is harmed and the other is unaffected
25. Exploitative Interactions: when one species benefits and the other is harmed
26. Niche: sum of habitat requirements and functional roles of a species
27. direct competition: ability to acquire and defend exclusive use of resources (territory, food, etc)
28. indirect competition: ability to use a scarce resource more effectively than the competitor (the other
species cannot even detect the resource whilst the "winner" is using it up)
29. Competitive Exclusion Principle: Ecological rule that states that no two species can occupy the same
exact niche in the same habitat at the same time, they would die!
30. Conditions of Coexistence: 1) divide space/ different habitat
2) have different competitive strengths (limited by different factors)
3) evolve to avoid competition (Niche overlap over long periods of time)
31. Fundamental Niche: The full potential range of the physical, chemical, and biological factors a species
can use if there is no competition from other species.
2/7
