AP Biology - Ecology Chapter 52-56

Climate

Climate influences the distribution of organisms

• Temperature, precipitation, sunlight, and wind

Global Climate patterns are determined by input of solar energy and Earth’s movement in space

Regional and Local Climates can vary seasonally and be modified by other factors

• Earth’s axis of rotation and orbit around the sun/sun’s changing angles

• Seasonal changes in wind can alter ocean currents

Bodies of water - will moderate the climate of nearby land

Mountains - can cause rainforests or deserts

Microclimate - fine, localized patterns in climatic conditions

Terrestrial Biomes

Biomes - Major life zones characterized by vegetation or physical environment

• Affected by climate

• Climograph: Annual mean temperature vs. precipitation

• Ecotone and canopy

Disturbance - an event like a storm, fire, or human activity that changes a community, removing organisms and altering resource availability

• Some dominant plants depend on periodic disturbance

Topical Forest, Desert, Temperate Grassland, Savanna, Northern Coniferous Forest, Chaparral, Temperate Broadleaf Forest, Tundra

Aquatic Biomes

More characterized by their physical and chemical environment

• Freshwater < 0.1% salt and marine biomes around 3% of salt

• Oceans = largest marine biome - provide most of the rainfall and supply a lot of our oxygen

• Photic vs. aphotic - depends on light penetration (together = pelagic zone)

• Abyssal zone, benthic zone (benthos and detritus)

Thermocline - a layer of abrupt temperature change that separates warm upper layer from the cold deeper layers

Turnover - a mixing of waters that sends oxygenated water from the lake’s surface to the bottom and brings nutrient-rich water from the bottom to the surface.

Biomes include: Lakes, Wetlands, Streams/rivers, Estuaries, intertidal zones, oceanic pelagic zone, coral reefs, marine benthic zone

Distribution of Species

• Ecological factors and evolutionary history

Chapter 53 - Population Ecology

Population ecology - the study of populations in relation to their environment

Density

• Can estimate density from an indicator of population size like number or nests

• Mark-recapture method

• Adding to a population (birth and immigration) or depleting a population (death and emigration)

Dispersion patterns

• Clumped (most common)

  • Resources

  • Mating

  • Effectiveness of predation or defense

• Uniform

  • Secretion of chemicals that prevent plants from growing nearby it

  • Antagonistic social interactions - Territoriality

• Random

  • Absence of strong positives or negatives - seeds blown in the wind

Demographics

• Demography: study of statistics of populations and how they change over time

• Life table: summarizes the survival and reproductive rates of individuals in specific age-groups within a population

  • Use a cohort and follow them from birth till death

  • Usually focus on female births

• Survivorship curves

  • Survival rate data represented graphically

Types of curves

• Type 1: usually large mammals that produce few offspring but provide good care

• Type 2: Intermediate, constant death rate over the organism’s life span

• Type 3: organisms that produce large numbers of offspring but provide little or no care

Reproductive Rates

• How to estimate the number of breeding females?

  • Direct counts and Mark-recapture

  • Molecular tools - produce a genetic profile for captured females and then extract DNA from their eggs/young and match it to a female

• Age-specific reproductive rates

Changes in population size

• Ideal, unlimited environment: Change = births + immigrants - deaths - emigrants

  • Sometimes can ignore immigration and emigrants: Change in population/Change in time = B-D