Exam 1

Ecology

Ecology

The study of the distribution and abundance of organisms and the interactions of organisms with their biotic and abiotic environments

What are 4 aspects of ecology?

1. Natural selection, evolution, adaptation

2. Life history variation, behavioral and environmental change

3. Inter-specific interactions, population dynamics, disease

4. Diversity, spatial patterns, and ecosystem processes

What are the 5 levels of organization?

1. Individual

2. Population

3. Community

4. Ecosystem

5. Biosphere

Dynamic Steady State

Losses and gains of an ecological system are in balance

Evolution

Change in genetic composition of a population over time

Natural Selection

Survival and reproduction of the fittest - one of the mechanisms of evolution

What does natural selection require to occur?

Natural selection requires heritable trait variation corresponding with variation in fitness

Producers / Autotrophs

Convert light/chemical energy into resources

Consumers / Heterotrophs

Obtain their energy from other organisms

Scavengers

Consume dead animals

Detritivores

Break down dead organic matter (i.e., detritus) into smaller particles

Decomposers

Break down detritus into simpler elements that can be recycled

What are the 2 main categories for species based on energy source?

Producers and consumers

What are the 3 other subtypes of consumers?

Scavengers, detritivores, and decomposers

What are the 6 types of species interactions?

1. Predation/parasitoidism

2. Parasitism

3. Herbivory

4. Competition

5. Mutualism

6. Commensalism

Niche

The range of abiotic and biotic conditions an organism can tolerate

What are the 2 types of studies?`

1. Observational studies

2. Manipulative field experiments

What are 3 types of manipulative field experiments?

1. Microcosm experiments

2. Laboratory experiments

3. Mathematical models

Weather vs Climate

Weather: describes current conditions, irregular and unpredictable Climate: long-term patterns, based on averages and variations over decades

What are the 4 things spatial climate patterns depend on?

1. Unequal heating with latitude and season

2. Air circulation and coriolis effect

3. Ocean currents

4. Misc. other impacts of land and water

Greenhouse Effect

The process of solar radiation striking Earth, being converted to infrared radiation, and being absorbed and re-emitted by atmospheric gases

The different patterns of heating are due to what 3 reasons?

1. Distance ray needs to travel

2. Angle the ray hits the earth

3. Density of ray distribution

Solar Equator

The latitude receiving the most direct rays of the Sun

What is the latitude for March and September Equinox?

0° latitude

What is the latitude for the June solstice?

23.5° N (tropic of Cancer)

What is the latitude for the December solstice?

23.5° S (tropic of Capricorn)

Where are Hadley Cells?

Between the solar equator and 30° latitude

Where are Polar Cells?

Between 60° and 90° latitude

Easterlies

Winds move NE to SW in northern hemisphere and SE to NW in the southern hemisphere

Where are Ferrel Cells?

Between Hadley and Polar Cells

What is the Intertropical Convergence Zones (ITCZ)?

Area where 2 Hadley cells converge and cause large amounts of precipitation

How many wet seasons are there at the tropics of Cancer and Capricorn and how many at the equator?

1 wet season at the tropics, 2 wet seasons at the equator

Where is the air circulation from convection cells deflected to in the northern hemisphere?

To the right

Where is the air circulation from convection cells deflected to in the southern hemisphere?

To the left

Northeast Trade Winds

Air on surface in Northern Hadley Cell moves from NE to SW

Southeast Trade Winds

Moves from SE to NW

Westerlies

General mid-latitude movement from W to E

What direction do the ocean currents circulate in the north and south?

Clockwise in the north, counter-clockwise in the south

Gyres

A large system of rotating ocean currents

Upwelling

A process in which deep, cold water rises toward the surface

What happens during El Nino-Southern Oscillation (ENSO)?

Trade winds near Peru that normally cause upwelling will reverse (oscillate) leading to a poor fishing harvest and increased rain

Which hemisphere has more rainfall and less variable temperatures?

Southern hemisphere because it has 81% water (northern has 61%)

Biome

A geographic region that contains communities composed of organisms with similar adaptations

What are the 4 things that determine a biome?

1. Climate

2. Soil

3. Fire

4. Grazing regimes

What are the 9 terrestrial biomes?

1. Tropical rainforest

2. Tropical seasonal forest/savanna

3. Subtropical desert

4. Woodland/shrubland

5. Temperate seasonal forest

6. Temperate grassland/cold desert

7. Temperate rainforest

8. Boreal forest

9. Tundra

What are the 3 temperature ranges for the terrestrial biomes?

<5° C, 5-20°C, and >20°C

What is Whittaker's Climate Diagram?

A diagram that links the 9 biomes with precipitation and temperature

Where are tropical rainforests found?

Near the equator (ITCZ)

What are the 5 determining factors of soil?

(CLORPT)

1. Climate

2. Organisms

3. Relief

4. Parent material

5. Time

Population

A group of individuals of the same species living in the same place

Population Growth Rate

The number of new individuals produced per unit of time minus the number that die

Density Independent Factors (limit population growth)

Factors not related to population density (ex. floods, temperatures, etc.)

Density Dependent Factors (limit population growth)

Factors related to population density, often biotic (ex. disease, competition for food/space, etc.)

What is negative density dependence?

High population density leads to negative population growth; birth rate decreases and death rate increases (ex. intraspecific competition, disease, etc.)

What is positive/inverse density dependence (Allee Effect)?

Low population density leads to low or negative population growth (ex. inability to find mates or forage, etc.)

Carrying Capacity (K)

The maximum population supported by the environment

What happens when a population is above K?

Negative population growth because of low reproduction and survival

When do we see the maximum observed growth rate (dN/dt)?

When N = K/2

What are 3 reasons for why logistic models of populations may not be accurate?

1. Environmental variability

2. Populations can overshoot K (could lead to extinction)

3. Complex dynamics; cycles and chaos

Survivorship (lx)

The probability of surviving from birth to any later age class

What are the 3 types of survivorship curves?

1. Type I: High mortality late in life (ex. humans)

2. Type II: Constant mortality (ex. birds)

3. Type III: High mortality early in life (ex. trees)

What are the 2 ways to collect data for life tables?

1. Cohort approach

2. Static approach

Cohort Approach (Data Collection)

Follow a group of same-aged individuals throughout lives

Static Approach (Data Collection)

All individuals of all ages at a particular point in time (snapshot)

What 2 parts make up the concept of scaling?

1. Spatial extent of ecological processes and spatial interpretation of the data

2. Organism response to the environment is particular to a specific scale

What are the 6 breakdowns of spatial scaling? (largest to smallest)

1. Global

2. Continental

3. Biome

4. Region

5. Landscape

6. Local community

Spatial distributions of populations are limited by what?

Their niche to ecologically suitable habitats

Competitive Exclusion

Species with the same niche cannot coexist indefinitely

Fundamental Niche

The range of abiotic conditions under which a species can exist

Realized Niche

The range of abiotic and biotic conditions under which a species can exist

What are the 5 attributes of population distribution?

1. Geographic range

2. Abundance

3. Density

4. Dispersion

5. Dispersal

What is a geographic range?

A measure of the total area covered by a species (reflects realized niche)

Geographic range is limited by what 5 things?

1. Abiotic conditions (climate, etc.)

2. Habitat availability

3. Species interactions (competitions, natural enemies, hosts, mutualists, etc.)

4. Dispersal

5. Source-sink dynamics

Climate Envelope

The suitable climate conditions for a species

Habitat Availability

Populations are limited to suitable habitat patches within that range due to smaller scale variation

Abundance

The total number of individuals in a population that exist within a defined area

Population Density

The number of individuals per unit area or volume

What are the 2 ways to measure population size?

1. Census; count all (small populations only)

2. Surveys

How do you do capture-mark-recapture to measure population size?

To estimate abundance (N), capture and mark a # of animals (M), release back into the population, return and capture a # of animals from the same population (n), count how many were already marked (X), and set up a ratio

What are the 3 assumptions of capture-mark-recapture?

1. Animal markings don't get lost

2. Equal likelihood of catching unmarked and marked animals (enough mixing)

3. No change in population size during sampling (no births, deaths, immigration, emigration, etc.)

Dispersion

The description of the distribution of organisms relative to one another

What are the 3 types of dispersions?

1. Clustered

2. Evenly spaced

3. Random

What are the 3 things that can cause clustered dispersion?

1. Clustered resources

2. Social behavior

3. Limited dispersal

What are the 2 things that can cause evenly spaced dispersion?

1. Depleted resources

2. Aggressive social interaction (competition, territoriality, etc.)

How do you measure dispersion?

Using variation/mean ratio

How do you know what dispersion the population follows using the variation/mean ratio?

1. Clustered > 1

2. Evenly spaced < 1

3. Random ~ 1

Dispersal

Movement of individuals from one area to another; displacement of offspring from parents, to avoid predation, competition, inbreeding, possible colonization of new areas (not the same as back and forth migrations in response to changing conditions)

Population Structure

Subdivision of organisms into subpopulations living in suitable patches of habitat surrounded by matrix

Matrix

Unsuitable habitat

What are the 3 models of population structures?

1. Basic metapopulation model

2. Source-sink model

3. Landscape model

Metapopulation

Set of populations or sub-populations of a species linked by dispersal

Basic Metapopulation Model

Suitable habitat patches (equal equality) embedded within a matrix of unsuitable habitat

What are the 2 categories of habitat patches in the source-sink model?

1. Sources

2. Sinks

Sources

High quality habitat and + population growth without emigration; provides dispersers

Sinks

Poor quality habitat and - population growth without immigration; rely on dispersers

What does the landscape model do?

Incorporates variation in matrix quality and habitat conductivity; more realistic

Ideal Free Distribution

Individuals distribute among different habitats so that they have the same per capita benefit

Life History

An organism's schedule of growth, development, fecundity, and death

What is the name of the continuum related to life histories?

Fast(r)-slow(K) continuum

What are 4 characteristics of "fast" life history / "r-selected"

1. Early maturity and short lifespan

2. High # of offspring

3. Little parental investment per offspring

4. Traits increase population growth