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BIOL-304-02 > BIOL 304: Midterm 2 Guide > Flashcards

BIOL 304: Midterm 2 Guide Flashcards

Covers Lecture 9-16

1
Q

Lincoln Peterson Formula:

A

𝑁 = MC/R

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2
Q

Logistic Equation of Population Growth:

A

𝑑𝑁/𝑑𝑑= π‘Ÿπ‘ (1 βˆ’π‘/𝐾)

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3
Q

What does each letter represent in the logistic equation of population growth?

A

-dN/dt= instant growth rate in a population
-r= intrinsic growth rate
-N= population size
-K= carrying capacity

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4
Q

Geometric Equation of Population Growth:

A

𝑁𝑑 = 𝑁0πœ†π‘‘

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5
Q

What does each letter represent in the geometric equation of population growth?

A

-N(t)= population size at time of t
-N(0)= initial population size
-πœ†= finite growth rate/ rate of increase
-t= time

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6
Q

Exponential Equation of Population Growth:

A

𝑁𝑑 = 𝑁0π‘’π‘Ÿπ‘‘

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7
Q

What does each letter represent in the exponential equation of population growth?

A

-N(t) = population size at time t
-N(0)= initial population size
-r= intrinsic growth rate
-e= Euler’s number
-t= time

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8
Q

Basic Model of Meta Population Dynamics Formula:

A

𝑝̂= 1 – 𝑒/𝑐

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9
Q

What is the relationship between r and Ξ»:

A

Ξ» = er
r = loge Ξ»

The intrinsic rate of increase (r) and the finite rate of increase (Ξ») are directly related to each other.

Ξ» relates to r: calculates Ξ» based on intrinsic growth rate

r relates to Ξ»: calculates r based on finite rate of increase

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10
Q

What are the three models of population growth that we have discussed, and how do they differ?

A
  1. Geometric
  2. Exponential
  3. Logistic
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11
Q

The Geometric Population Growth Model:

A

Appropriate for organisms that reproduce at discrete time intervals (annually, seasonally, etc)

The exponential and geometric models express essentially the same thing: with one describing continuous reproductive events, and the other describing periodic reproductive events (exponential curve)

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12
Q

The Exponential Population Growth Model:

A

Appropriate for organisms that reproduce a seasonally or continuously

Unlike the geometric model, the exponential models gives a continuous estimate, which is represented with a J curve

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13
Q

The Logistic Population Growth Model:

A

More realistic model that takes into account carrying capacity (k). It predicts an S curve where growth slows down as the population approaches carrying capacity and eventually levels off.

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14
Q

What is carrying capacity and what factors affect it?

A

(K) is the maximum population size that can be supported by a given environment.

(K) differs for a given species as a function of environmental variables and is affected by factors such as:
-Resource availability (food, water, shelter)
-Habitat quality (space and changing abiotic or biotic conditions)
-Predation
-Disease

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15
Q

What is delayed density dependence and how does it impact population growth patterns?

A

Occurs based on a population density at some time in the past / situations where the negative effects of high population density take time to impact the population

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16
Q

What is overshoot?

A

When a population grows beyond its carrying capacity

Ex: Sudden increase in birth/death rates or decrease in K

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17
Q

What is die off?

A

Follows overshoot, represents a significant decline in population in a given area

Resource depletion and increased competition take hold, causing populations to crash back below the carrying capacity

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18
Q

What are stable limit cycles?

A

Population size continues to exhibit large oscillations overtime following a perturbation

Think of a constantly spinning gear, with consistent ups and downs

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19
Q

What is damped oscillation?

A

Population size initially oscillates following change, but the magnitude of the oscillation declines over time, eventually stabilizing

Think of a pendulum gradually coming to rest

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20
Q

Compare stable limit cycles and damped oscillations:

A

-Both involve fluctuations around an equilibrium point
-Driven by ecological interactions
-Modeled by mathematical equations

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21
Q

Contrast stable limit cycles and damped oscillations:

A

Stable Limit Cycles:
-Constant amplitude fluctuations
-Perpetual oscillations
-Specific conditions promoting self-sustaining cycles

Damped Oscillations:
-Decreasing fluctuations
-Reaches stable population level
-Factors return population to equilibrium

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22
Q

What are the three models of metapopulation dynamics?

A
  1. Basic Metapopulation Model
  2. Source-Sink Model
  3. Landscape Model
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23
Q

The Basic Metapopulation Model:

A

Uses extinction and colonization rates to predict the average probability of patch occupancy

-Equal patch quality
-Suitable patches embedded in uninhabitable matrix
-Some patches are unoccupied at any given point in time

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24
Q

The Source-Sink Model:

A

Relaxes the assumption of equal patch quality; High quality patches produce disproportionately more dispersers (source populations); Low quality patches produce disproportionately fewer dispersers (sink populations)

-Patches vary in quality: refinement of the basic model
-High quality patches produce more than low quality patches
-Low quality patches depend on immigrants to maintain a viable subpopulation (sink subpopulations)

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25
Q

The Landscape Model:

A

Relaxes the uniform matrix (non-patch portion of the landscape) assumption, allowing dispersal barriers to modify the colonization and extinction probabilities of patches independent of patch size and quality

26
Q

Why is extinction probability higher for smaller populations?

A

ALL populations go extinct. The smaller a population gets, the higher the probability of extension in a given time interval.

Smaller populations are more vulnerable to:
Genetic drift: random fluctuations in allele frequencies can lead to loss of beneficial genes.
Stochasticity (environmental/demographic): variation in birth and death rates

27
Q

What are type I, II, and III survivorship curves, how are they depicted, and why do they differ?

A

The shape of a survivorship curve reflects the evolutionary strategies a species adopts to ensure reproductive success. Factors like parental care, resource availability, predation pressure, and generation time all influence how a population allocates resources and experiences mortality throughout its life cycle.

28
Q

Type I Survivorship Curve:

A

High survival in early life stages, followed by a sharp decline in later stages

Convex curve (starts high, stays relatively flat, dips sharply at older ages, like a bell curve shifted to the right)

Ex: humans, elephants, theropods, ungulates

29
Q

Type II Survivorship Curve:

A

Relatively constant survival rate throughout life

Diagonal curve (straight line negative slope)

Ex: birds (especially migratory), rodents

30
Q

Type III Survivorship Curve:

A

High mortality in early life stages, followed by higher survival rates later on

Concave curve (starts high and drops rapidly at the beginning, levels out or increases slightly in later life, J curve flipped horizontally)

Ex: many plants, sessile marine mollusks, many fish, amphibians

31
Q

What is species richness?

A

The number of species present in a community

32
Q

What is species evenness?

A

A comparison/measure of the relative abundance of each species in a community

33
Q

What information does rank abundance curves depict?

A

Plots the proportional abundance of each species relative to the others in rank order, from most to least abundant

34
Q

How are Ξ±, Ξ², and Ξ³ diversity related?

A

All measures of species diversity in ecology, but capture diversity at different scales

Gamma diversity (Ξ³) is a combination of alpha (Ξ±) and beta (Ξ²)

Changes in one can influence the other; habitat loss within a landscape can decrease gamma diversity (Ξ³) by reducing the total number of habitats (which affects alpha diversity, Ξ±) and increasing similarity between remaining habitats (lower beta diversity, Ξ²)

35
Q

What is Ξ± Diversity?

A

AKA Local Diversity

The number of species in a small area of homogenous habitat

36
Q

What is Ξ² Diversity?

A

The difference (β€œturnover”) in species from one habitat to another

37
Q

What is Ξ³ Diversity?

A

AKA Regional Diversity

The number of species observed in ALL habitats within a LARGE geographic area that includes no significant barriers to dispersal

38
Q

What are trophic levels?

A

Categorize organisms based on their position in the food chain

-Producers (primary producers)
-Primary Consumers
-Secondary Consumers
-Tertiary Consumers
-Decomposers

39
Q

What is a trophic cascade?

A

A β€œripple effect” that occurs when a change in consumption at one trophic level results in species abundance or commotion at lower trophic levels

Ex: Removing a top predator can lead to the abundance of herbivores, which can then overgraze plant populations, impacting the entire ecosystem

40
Q

What is top-down control?

A

The influence of predators on the populations of organisms lower in the food web.
-Importance of top predators
-Predator abundance impacts lower levels
-Cascading effects

41
Q

What is bottom-up control?

A

The influence of resources at the lowest trophic level (producers) on the populations of organism higher in the food web
-Importance of primary producers
-Resource abundance drives consumer populations
-Limited resources, limited consumers

42
Q

What is the relationship between carrying capacity and maximum sustainable yield?

A

Carrying capacity (k) is the maximum population size an environment can support.
Maximum sustainable yield is the highest rate at which a renewable resource can be extracted without depleting the population it sustains.
Maximum sustainable yield occurs below the carrying capacity to ensure long long-term viability of the population.
If resource extraction exceeds maximum sustainable yield, it can lead to population decline and ecosystem collapse.

43
Q

What is a source population?

A

Thrives in a high-quality habitat, offering ideal conditions for survival and reproduction:
-High birth rates and low death rates
-Net exporter of individuals: with a surplus population, more individuals emigrate compared to those immigrating

44
Q

What is a sink population?

A

Occupies a lower-quality habitat, presents challenges for survival and reproduction:
-High death rates and low birth rates
-Reliant on immigration: without a steady influx of individuals from source populations, sink habitats wouldn’t be able to sustain their populations in the long run

45
Q

What two rates are used in the Equilibrium Model of Island Biogeography?

A
  1. Colonization rate
  2. Extinction rate
46
Q

What do the equilibrium points in figure 18.21 in your book indicate?

A

From left to right in order:
1. S(small, far)
2. S(large, far)
3. S(small, near)
4. S(large, near)

47
Q

What does the Equilibrium Model of Island Biogeography express? i.e, What does it predict?

A

Predicts that species diversity or β€œrichness” on an island is positively related to the size of the island, but negatively related by the island’s distance to the mainland.

48
Q

What empirical (experimental) evidence supports the Equilibrium Model of Island Biogeography?

A
  1. Species-Area Relationship
  2. Distance Effect
  3. Turnover Rates
49
Q

What are alternative stable states?

A

Different stable community types that are possible for a given ecosystem

Ex: large herbivores present/absent, healthy coral reef/bleached-algae dominated

50
Q

What are climax communities?

A

The end point of a successional sequence; a community that has reached a steady state under a particular set of environmental conditions

51
Q

What are stable states?

A

The point at which a community develops long-term resistance to change in structure, function, and species composition

52
Q

What is succession?

A

The change in species composition, structure, and function of a biotic community through time

(Ex: establishment of forests, filling of lakes and ponds)

53
Q

What is primary succession?

A

Proceeds on a substrate that has not previously supported a biotic community

(Ex: lake formation in an abandoned quarry/impact crater, volcanic disruption)

54
Q

What is secondary succession?

A

Proceeds on a substrate that has previously supported a biotic community

(Ex: post-burn regrowth, β€œold-fields”

55
Q

What is the difference between primary and secondary succession?

A

Primary succession refers to community development on new substrates, whereas secondary succession refers to community development where communities have existed before.

56
Q

What does a food web represent?

A

The complex network of feeding relationships within a community. It shows how energy and nutrients flow through the ecosystem from one organism to the next.

57
Q

What is the difference between a food web and an interaction network?

A

Although they both analyze community organization and the role of complexity in coexistence and stability…
Food webs focus on the mass flow through communities
Interaction networks focus on specialization vs. generalization

58
Q

What is a food web?

A

A food webs allows the analysis of:
-Mass flow through communities
-Community organization
-Role of complexity in coexistence and stability

59
Q

What is an interaction network?

A

An interaction network allows the analysis of:
-Specialization vs. generalization
-Community organization
-Role of complexity in coexistence and stability

60
Q

What is functional redundancy and how does it relate to ecosystem stability?

A

Functional redundancy is the overlapping functional roles among species within a community.
Ecosystem stability is the degree to which the structure and function of an ecosystem remain stable when facing alterations/changes.
Functional redundancy promotes ecosystem stability

61
Q

T/F) Biodiversity is higher in the tropics and decreases with latitude

A

True

BIOL-304-02 (10 decks)

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