Ecology Exam 2 pt 3 (Lord Pls) (Chapters 8, 9, and 11)

Unitary organisms

Unitary vs. Modular Organisms (8.1)

Have a predictable form and life cycle (most animals):

Modular organisms

Unitary vs. Modular Organisms (8.1)

Grow by adding repeating units; made of parent plants and clones (most plants, corals):

Geographic Range

Distribution (8.2)

The spatial location where a species is found:

Random, Uniform, and Clumped (Aggregated)

Distribution (8.2)

What are the three Spatial Patterns?:

Random - equal probability of being anywhere

Distribution (8.2)

Define this spatial pattern:

Uniform - evenly spaced out due to competition/territory

Distribution (8.2)

Define this spatial pattern:

Clumped (Aggregated) - Grouped together in patches

Distribution (8.2)

Define this spatial pattern:

Abundance

Abundance & Density (8.3)

Total number of individuals in a population:

Population Density

Abundance & Density (8.3)

Number of individuals per unit area/volume:

Ecological Density

Abundance & Density (8.3)

Density calculated relative to available suitable habitat space (since habitats aren’t uniform):

Sessile (Stationary) Organisms

Sampling Populations (8.4)

Sampled using sample plots/quadrats:

Mobile Organisms

Sampling Populations (8.4)

Sampled using capture-recapture techniques or relative abundance signs (tracks, vocalizations):

Pre-reproductive, Reproductive, Post-reproductive

Age, Stage, and Size Structure (8.5)

Divided into what 3 ecological periods?:

Growing population

Age, Stage, and Size Structure (8.5)

High percentage of young individuals:

Declining population

Age, Stage, and Size Structure (8.5)

High percentage of older individuals:

Starts near 1:1 at conception/birth. - Shifts over time due to age-specific mortality rates.

Sex Ratio (8.6)

Where is sex ratio usually seen?:

Dispersal

Dispersal & Population Dynamics (8.7 & 8.8)

Movement of individuals across space (passive via wind/water, or active):

Migration

Dispersal & Population Dynamics (8.7 & 8.8)

Round-trip, directional movement between locations:

Spatial distribution, population density, birth/death rates

Dispersal & Population Dynamics (8.7 & 8.8)

What do dispersal dynamics drive?:

Non-native species introduced to new areas that negatively impact native species and ecosystems.

Invasive Species (8.9)

Define invasive species:

Exponential Growth

Population Growth (9.1)

Occurs when births exceed deaths in an ideal environment w/o limiting factors; represented as continuous:

Intrinsic Rate of Increase ( r )

Population Growth (9.1)

The difference between instantaneous per capita birth rate (b) and death rate (d):

Life Table

Life Tables (9.2 & 9.3)

An age-specific summary of mortality and survival within a population:

Cohort (Dynamic) Life Table

Life Tables (9.2 & 9.3)

Follows a group of individuals born at the same time from birth until all have died:

Time-specific (Static) Life Table

Life Tables (9.2 & 9.3)

Samples a population at a single point in time to determine the age distribution across classes:

Type I Curve

Mortality and Survivorship Curves (9.4)

High survival rate throughout life; high mortality late in life (e.g, humans, large mammals):

Type II Curve

Mortality and Survivorship Curves (9.4)

Constant mortality/survival rate throughout all age classes (e.g, birds, reptiles):

Type III Curve

Mortality and Survivorship Curves (9.4)

Very high mortality in young age classes, but high survival for those who reach adulthood (e.g., fish, invertebrates, plants):

Gross Reproductive Rate

Birthrate & Net Reproductive Rate (9.5 & 9.6)

Total average number of female offspring born to a female over her lifespan:

Net Reproductive Rate (R₀)

Birthrate & Net Reproductive Rate (9.5 & 9.6)

Average number of female offspring produced by a female during her lifetime, taking into account age-specific survival rates:

Equal to 1

Birthrate & Net Reproductive Rate (9.5 & 9.6)

Population is stable if R₀ is —:

More than 1

Birthrate & Net Reproductive Rate (9.5 & 9.6)

Population is growing if R₀ is —:

Is less than 1

Birthrate & Net Reproductive Rate (9.5 & 9.6)

Population is declining if R₀ is —:

Combines age-specific survival/birth rates to project future population size/age structure

Population Projection Table (9.7)

Define population projection table;

Finite Rate of Increase

Population Projection Table (9.7)

The discrete rate of population growth from one time step to the next:

Demographic Stochasticity

Stochastic Processes (9.8)

Random variation in birth and death rates among individuals year to year:

Environmental Stochasticity

Stochastic Processes (9.8)

Random variations in environmental conditions (weather, food, natural disasters) that affect survival and reproduction:

Habitat destruction and Degradation

Extinction & Habitat Loss (9.9)

What are the two primary causes of species extinction?:

Lower overall population sizes and reduced growth rates

Extinction & Habitat Loss (9.9)

What des reductions in habitat size lead to?:

Carrying Capacity (K)

Logistic Population Growth (11.1)

The maximum population size that a specific environment can sustainably support over time due to resource limitations:

Logistic Model

Logistic Population Growth (11.1)

Models growth when resources are limited. Growth slows as the population size (N) approaches carrying capacity (K):

Birth rates decrease, mortality rates increase, population growth slows

Density-Dependent Regulation (11.2)

As population density increases, brith and mortality rates (?) causing population growth to (?):

Scramble Competition

Infraspecific Competition (11.3)

All individuals get an equal share of resources, which can lead to severe resource shortages for everyone if density is too high:

Contest Competition

Infraspecific Competition (11.3)

Dominant individuals secure full resources while subordinates get none, ensuring at least some individuals survive and reproduce:

Growth and Development

Effects of Competition (11.4 – 11.6)

Slowed or stunted growth at high densities:

Mortality

Effects of Competition (11.4 – 11.6)

Higher population density increases these rates, freeing up resources for remaining survivors:

Reproduction

Effects of Competition (11.4 – 11.6)

High density delays reproductive maturity and lowers fecundity (number of offspring):

Delayed reproduction, lower immunity, and abnormal behaviors

Density and Stress (11.7)

Crowing causes physiological stress in animals, leading to what?:

Dispersal

Dispersal & Social Behavior (11.8 & 11.9)

Subordinate or excess individuals leave crowded areas to seek open habitat:

Social Hierarchies

Dispersal & Social Behavior (11.8 & 11.9)

Dominant individuals secure priority access to food and mates, limiting reproduction to fewer individuals:

Territory

Territoriality (11.10 & 11.11)

A defended exclusive area containing essential resources:

Breeding Regulation

Territoriality (11.10 & 11.11)

Non-territorial individuals (“floaters”) are excluded from breeding, stabilizing overall population growth:

Plants

Territoriality (11.10 & 11.11)

Preempt space and resources (light, water, nutrients) by shading out or crowding neighbors:

Inverse Density Dependence (Alee Effect)

Inverse Density Dependence & Density-Independent Factors (11.12 & 11.13)

At extremely low densities, population growth rates decrease because individuals struggle to find mates/defend against predators:

Density-Independent Factors

Inverse Density Dependence & Density-Independent Factors (11.12 & 11.13)

Abiotic forces (weather, floods, fire, natural disasters) that affect survival regardless of population density:

Resource Quality

How effectively a specific resource meets an organism’s biological needs for survival, growth, and reproduction: