Midterm 1

Question 1

Ecology

Answer 1

How organisms interact with each other and the environment that determines distributions and abundances.

Traditional Knowledge:
- Passed on over generations of knowledge

Local Knowledge:
- Acquired and maintained by knowledgeable locals in the area.

Question 2

Testing

Answer 2

1. Observation of Question
2. Hypothesis
   - Null: focal factor does not have an effect
   - Alternative: focal factor does have an effect
3. Experiment
   - Alters/manipulates focal factors (even ones that don’t change with it) with goal to falsify the null hypothesis.
4. Results
5. Interpretation

Question 3

Climate

Answer 3

Weather trends in the long term.
- Drives species diversity and biome distribution.
- Movement of air affects climate conditions and patterns

Question 4

Solar Radiation

Answer 4

• Higher latitudes are colder because of slanted rays, diffusing more energy
• Lower latitudes are warmer because there’s less slant and rays are more concentrated.

Question 5

Coriolis Force

Answer 5

Because of the earth’s rotation, any object moving towards the north hemisphere is deflected right, while any object moving towards the south hemisphere is deflected left.
- Coriolis effect at the equator
- Happens because different points on the earth surface is moving at different speeds.

Question 6

Continental Effects

Answer 6

Differing heat capacities of water and soil lead to effects on the climate.
- Ex. Coastal areas has a moderating effect on the climate between summer and winter seasons.

Question 7

Aquatic Zones

Answer 7

Characterized by:
- Light and nutrient availability
- Temperature
- Structure of the benthic surface
- Salinity
- Movement of water

Question 8

Marine Zones

Answer 8

Characterized by:
- Light penetration
- Proximity to shoreline
- Physical location (benthic = on bottom surface. Pelagic = in water column)
- Depth of pelagic zones

Question 9

Freshwater Zones

Answer 9

Characterized as:
- Lotic (flowing rivers and streams)
- Lentic (stationary ponds and lakes)
- Aquifer (subsurface water)

Question 10

Limiting Factor

Answer 10

Resource or environmental condition that limits the growth, distribution or abundance of an organism or population within an ecosystem

Question 11

Niche

Answer 11

Set of environmental conditions in which an organism can live and reproduce.
- Determined by a species tolerance to its limiting factors

Question 12

Realized Niche

Answer 12

Set of enviromental conditions and resources in its full range it could use without any limiting factors like predators or competition.

Question 13

Fundamental Niche

Answer 13

The actual set of environmental conditions and resources the species uses in the real world.

Question 14

Autotrophs

Answer 14

Convert light/inorganic compounds into organic energy

Question 15

Heterotrophs

Answer 15

Obtain energy by consuming organic compounds from other organisms

Question 16

Principle of Allocation

Answer 16

Equation to determine where to prioritize their limited energy that is available. Allocating for one function reduces energy for the others.

Formula:
E-intake = E-respiration + E-assimilation + E-reproduction + E-waste.

Question 17

Optimal Foraging Theory

Answer 17

Predicts bets strategies for maximizing energy intake by considering energetic profitability of a food item.

Formula:
P = E/C
- E = energy gained from food
- C = energy costs associated with acquiring and eating the food.

Also:
P = E/(S+H)
- S = energy cost from searching
- H = energy cost from handling

Question 18

Polar Bears

Answer 18

Need sea ice to feed on seals.
- Longer ice free seasons lead to less time spent on ice.
- Then less energy reserved for the fast.
- Spends more time on land fasting which need energy reserves to survive the fast.

Question 19

Thermoreuglation Strategies

Answer 19

Poikilotherms: has no regulation
Ectotherms: use external factors like sun and shade to regulate
Endotherm: uses behavioral regulation and internal processes like shivering or metabolic heat
Homeotherms: are subtype of endotherm that regulate in a very narrow range.

Question 20

Climate Envelope Model

Answer 20

Strategy used for predicting climate change impacts:

Use statistical modelling to determine under what climate
conditions a species currently occurs. Subsequently, they consider climate projections to
figure out where those same conditions are likely to occur in the future to determine a likely
future range for the species

Question 21

Thermal Performance Population Models

Answer 21

Strategy used for predicting climate change impacts:

Try to estimate where a species could
occur based on its thermal constraints. Combining thermal performance curves for
development rate, birth rate, death rate, and other demographic variables, can yield estimates
of population growth rates under different temperature regimes. Combined with climate
projections, this approach can yield estimates of where the species is likely to occur in the
future.

Question 22

Population Growth

Answer 22

Population: group of individuals of same species in the same area
Abundance: number of individials
Density: number of individuals per unit area

Question 23

Obtaining Data Methods

Answer 23

Counting Species:
- for small areas
- want very accurate results
- not too many species

Community Reports:
- need local knowledge from people around
- information that is hard to observe form one person

Sampling plots:
- area is too large to count everything
- estimate abundance or diversity

Line Transects:
- area is large or long
- species are hard to count individually
- good for birds, mammals, and habitat that change

Question 24

Mark-Recapture Method

Answer 24

Method to obtain data.
- Provides absolute abundances estimates
- Uses camera traps

Formula:
N = (MxC)/R
- M = marked
- C = captured
- R = recaptured

Question 25

Geometric Population Growth

Answer 25

Open Population: N-t+1 = N-t + B-t - D-t + I-t - E-t Closed Population: Nt+1 = Nt + Bt - Dt - N = pop size - B = no. births - D = no. deaths - I = no. immigrants - E = no. emigrants Derived Form: Nt = λ^tN0 - λ = 1: pop stays same - λ < 1 pop declines - λ > 1 pop increases

Question 26

Discrete Time Population Models

Answer 26

These track population size from one time period to the next and are best for species that reproduce at specific times, like animals that have one big birth period each year. Calculate population size at the next time step as a function of population size at the previous time step Formula: Nt+1 = f(Nt) = Nt + increase - decrease and λ^t = (Nt/N0)^(1/t)

Question 27

Continuous Time Population Models

Answer 27

These account for population changes happening at any moment and are best for species that reproduce all the time, so their population changes continuously. Formula: dN/dt = f(N) = rate of increase - rate of decrease - dN/dt: means rate of change in population size - f(N): represents how rate depends on current pop size

Question 28

Exponential Growth

Answer 28

This happens when individuals reproduce all the time (not at specific times), like humans, and the growth rate stays the same over time. Formula: dN/dt = rN - dN/dt: means rate of change in population size - r: how fast each individual add to population (growth rate per person) - N: current population size Formula with time: N(t) = N(0)e^rt

Question 29

Growth Model Overlap (exponential and geometric)

Answer 29

λ = e^r r = ln(λ)

Question 30

Density-Independent Factors

Answer 30

Factors that affect birth rates, death rates, and other demograhic variables regardless of the size of population. (Weather, natural disasters, etc.)

Question 31

Density Dependence

Answer 31

Occurs when birth rates, death rates, and/or other demographic variables are directly affected by the density of the population. Decreases birth rates and increases mortality and emigration rate

Question 32

Logistic Growth

Answer 32

Assumes that the per capita population growth rate declines linearly as population density increases. Formula: dN/dt = rN(1 - (N/K)) - N= pop density - r = intrinsic per capita rate of increase - K = carrying capacity Assumptions: - changes in population abundance are occurring continuously - per capita birth and death rates are independent of the environment

Question 33

Negative Density-Dependence

Answer 33

Is suggested that low-density populations have high per capita growth rates and tend to grow towards carrying capacity. Actually not the case: - Smaller populations are more vulnerable to events, Alle effects, and other factors leading to probability of extinction.

Question 34

Allee Effect (Positive Density-Dependence)

Answer 34

This effect increases the per capita growth rate as population density increases at small population sizes. - Population's growth rate and individual fitness increase as densitiy increase.

Question 35

Stochastic Events

Answer 35

Causes fluctuations in population size and increase the risk of extinctions especially with larger fluctuations and smaller population sizes. Environmental Stochasticity: - Random variation from the external environment - Change in average birth and death rates in a time period - Caused by random changes in the environment Demographic Stochastisity: - Random variation of birth and death rate within the population - Primarily affects small populations - Individuals don't follow trends

Question 36

Matrix Models

Answer 36

Calculates growth trajectory for a stage-structured population.

Question 37

Dispersal

Answer 37

Movement by an individual to a location that isn't known or identified beforehand and usually doesn't return. - Reduces the probability of inbreeding - Avoids competition

Question 38

Migration

Answer 38

Movement by a group or individual at approximately the same time, often occured at a predictiable life stage or seasonally. Can be round trip events and spread over more than one generation. Happens only once in a lifetime

Question 39

Metapopulation

Answer 39

Set of distinct populations of a species that is spread across a landscape. Is linked to dispersal - Persists even if subpopulations go extinct, as long as dispersal and recolonization exists - Must be managed as a whole, maintaining occupoed and unoccupied habitats - Disconnecting or losing habitat patches implies the number of occupied patches will also decrease Equation: dp/dt = cp(1 - p) - ep - p = proportion of patches occupied - c = colonization rate - e = extinction rate - c>e: persists and reaches equilibrium - c