Biomes and Population Ecology Notes Unit 8 lecture 1

Definition: Biomes are the largest ecological groups that categorize environments based on weather patterns, particularly temperature and precipitation.
Biosphere: Encompasses all living things on Earth, with biomes existing beneath this level.

Temperature and Precipitation: Two critical factors shared among biomes that influence their ecosystems.
Tropical Forests: High temperatures with significant variability in precipitation; typically the most rain.
Temperate Broadleaf and Northern Coniferous Forests: Can receive rainfall comparable to tropical forests, but generally less precipitation overall.
Grasslands and Tundras: Include temperate grasslands, deserts, polar ice, and alpine tundra, which can have low precipitation levels similar to deserts.
Climate Overlap: Many biomes exhibit overlaps in temperature and precipitation; eg. deserts can appear in both temperate and tropical regions.

Tropical Rainforests: Located in the tropic band (between the Tropic of Capricorn and Tropic of Cancer), characterized by high rainfall and temperature.
Subtropical Regions: Areas slightly north or south of the tropics, such as parts of South Florida.
Grasslands: Comprise temperate grasslands (prairies, pampas) distinguished from tropical grasslands (savanna).
- Savanna: Tropical grassland, notably in Africa.
Chaparral: Coastal areas with dry conditions characterized by bushy vegetation, common in regions noted for wine production.
Tundra: Characterized by permafrost; includes Arctic tundra (northern) and alpine tundra (mountains). Sometimes termed deserts due to low precipitation.

Vegetation: Adaptations like CAM plants that conserve water in deserts; waxy surfaces in cacti to reduce moisture loss.
Animal Adaptations: Species like kangaroo rats obtain water metabolically; camels store fats in humps.

Desertification: Can occur when environments like grasslands experience reduced rainfall and become deserts.
Deforestation Impact: Cutting down rainforests leads to decreased rainfall due to reduced transpiration, escalating desertification processes.
Global Issues: The effects of climate change have significant implications for preserving environments and preventing biome shifts.

Importance: Focuses on populations of a single species in relation to their environment, studying dynamics like density, distribution, age structure.

Population: A group of individuals of the same species living in a defined area.
Density and Dispersion:
- Density: Number of individuals per unit area or volume.
- Dispersion: Patterns of spacing (e.g., uniform, clumped, random).
Demographics: Statistics related to population dynamics—birth rates, death rates, migration.
Cohorts: Groups followed for studying survival statistics.

Capture-Recapture Technique: Method for estimating populations by marking a sample and calculating the total based on re-sampling.
Life Tables: Provide age-specific survival and reproduction statistics, indicating trends like longevity differences between sexes.

Birth and death rates are primary influences on population size, along with immigration and emigration.
Environmental and social factors can influence how individuals in a population are distributed—resource availability and territoriality are significant factors.

Examples from field studies demonstrate practical applications of population ecology, such as the use of radio collars to monitor deer movement and behaviors.

Biomes are defined largely by temperature and precipitation patterns.
The study of population ecology is vital to understanding dynamics affecting species and their environments.
Climate change poses a threat to the integrity of biomes, emphasizing the need for conservation efforts to maintain ecological stability and diversity.