Ecology Exam 3

Population

Group of interbreeding individuals of same species

Torpor

Physiological state of decreased activity and metabolism

Estivation

Summer torpor- avoid extreme heat and dry conditions, common to desert animals

Diapause

Period of suspended animation, common in insects (cocoon, chrysalis)

Extended torpor

Extended period of torpor punctuated by wakefulness and mild activity mid-winter. BEARS

Abundance

Population size (N)

Species range

Geographic distribution of a species

Endemic species

Have a specific range of geographic distribution, often found in restricted habitat conditions

Ubiquitous species

Have a broad range of geographic distribution, can inhabit a wide range of conditions

Dispersion

Pattern of spacing among individuals (clumped, random, uniform)

Emigration

Individual(s) leaving a subpopulation

Dispersal

Type of emigration where individuals move away from parent or habitat where they were born (might not leave population). Can be passive (via wind, water, animals) or active (walking, flying)

Immigration

Individual(s) moving into a subpopulation

Migration

Round-trip movement made by an animal population (daily, seasonal, short or long range)

Crude density

number of individuals per unit area or per unit volume

Ecological density

individuals per available unit of living space

Cohort

group of individuals born in the same period of time

x

Age class

n_x

number of individuals that are alive at specified age (x)

l_x

probability of surviving to any given age (x) from birth

d_x

Age-specific mortality

Number of individuals dying in age class

q_x

age-specific mortality rate (d_x/n_x)

Survivorship curve

Plots l_x vs age (x)

Type 1 Survivorship

survival rate is high throughout life span with heavy mortality at end

Type 2 Survivorship

survival rates do not vary with age

Type 3 Survivorship

mortality rates are extremely high in early life

b_x

mean number of females born to female in each age group (x)

Gross reproductive rate

average number of female offspring born to female over her lifetime IF she lives to life expectancy. Sum of b_x

Fecundity table

combines survivorship (l_x) with age-specific birthrates (b_x)

l_xb_x

mean number of females born in each age group, adjusted for survivorship

Net reproductive rate

R₀- Sum of l_xb_x

Allee effect

decline in reproduction or survival under conditions of low population density

Carrying capacity (K)

maximum sustainable population size for prevailing habitat conditions

Logistic growth

dN/dt = rN(1 – N/K)

Inflection point

Point on curve where growth rate is highest, N=K/2. Growth rate decreases after inflection point.

Adventitious roots

Roots that emerge above flooded, saturated area where oxygen is available

Pneumatophores

Growths of root systems of plants where water table fluctuates. Hollow growths that function like a snorkel to provide oxygen to the roots

Vascular tissue

Transport nutrients within plant

Ventilation

Movement of respiratory medium over respiratory surface. Required to maintain pressure gradient for gas exchange

Gills

Folded body tissue suspended in water

Crop

food reservoir in granivores (seed-eating birds)

Proventriculus

Part of stomach in granivores. Secretes enzymes to begin digestion

Gizzard

Part of stomach in granivores. Hard grinding organ, traps pebbles and bones

Cellulose and lignin

Found in plants- indigestible. Microorganisms needed to help digest

Homeostasis

Maintaining steady state of internal conditions despite changing environmental conditions. Maintained by feedback control loops (stimulus → response)

Osmoregulation

Process of controlling solute concentrations and water balance

Endothermy

Heat mainly acquired through metabolism (internally)

Homeothermy

Generally results from endothermy.

Consistent body temperature over time

High metabolic rate

Ectothermy

Heat acquired primarily from external environment

Poikilothermy

Generally results from ectothermy.

Body temperature varies over time.

Low metabolic rate, narrow operative temperature range