CHapter 4 - Understanding the Environment & Biomes Flashcards

Vocabulary flashcards covering ecological principles, biological hierarchies, climate dynamics, soil profile horizons, and the characteristics of terrestrial biomes based on the lecture material.

Ecology

The study of the relationships of organisms to one another AND to their physical surroundings.

Biotic Factors

The living components or organisms within an environment that influence its structure and ecosystem function.

Abiotic Factors

The nonliving physical and chemical components of an environment, such as sunlight, temperature, water, air, soil, and humidity.

Organismal Ecology

The subdiscipline of ecology that focuses on how individual organisms adapt physiologically and behaviorally to their environment.

Population Ecology

The subdiscipline of ecology concerned with all individuals of a single species inhabiting a specific geographic location.

Community Ecology

The subdiscipline of ecology that studies interacting populations of all species coexisting in a particular location.

Ecosystem Ecology

The subdiscipline of ecology that examines all biotic communities alongside abiotic factors interacting within a designated site.

Individual

A single living being that possesses a cellular structure and can independently carry out all physiological functions required for life.

Species

The basic unit of biological classification, defined as a group of organisms that actually or potentially interbreed in nature.

Population

A group of organisms of the same species living in the same area at the same time.

Community

An interacting group of various species sharing a common geographic location.

Ecosystem

A biological community of interacting organisms (biotic) together with their nonliving physical environment (abiotic).

Biome

A major, distinct biogeographical community that has developed in response to a shared, regional climate and environment.

Biosphere

The worldwide sum of all ecosystems on Earth, often described as the global zone of life.

Angle of Incidence

The angle at which solar radiation strikes Earth's surface; at higher latitudes, light strikes at a lower angle and spreads solar energy over a greater surface area.

Transit Distance

The distance solar light travels through the atmosphere; higher latitudes require light to pass through a thicker atmospheric segment, increasing absorbance and scattering.

Axial Tilt

The inclination of Earth's rotation axis at approximately $23.5^\times$ relative to perpendicular, which causes seasonal variations in solar intensity across latitudes.

Subpolar Point

The specific location on Earth's surface where the sun is positioned directly overhead (perpendicular) at solar noon.

Hadley Cells

Solar-driven atmospheric circulation cells where warm moist air rises at the equator, moves poleward, cools, and descends dry around $30^\times\text{ N}$ and $30^\times\text{ S}$ latitude.

Coriolis Effect

The deflection of moving objects or air masses viewed from a rotating reference frame, deflecting surface winds right in the Northern Hemisphere and left in the Southern Hemisphere.

Adiabatic Cooling

The reduction in air temperature caused by a decrease in atmospheric pressure as air rises to higher altitudes.

Lapse Rate

The rate at which atmospheric temperature decreases as altitude increases.

Dry Lapse Rate

The temperature decrease rate for dry rising air, measured at approximately $10\,^\times\text{C/km}$ or $5.5\,^\times\text{F}$ per $1000\,\text{ft}$.

Orographic Lift

The forced upward movement of air when an air mass encounters an elevated landform, such as a mountain range.

Windward Side

The side of a mountain range that faces the prevailing wind, characterized by forced air ascent, heavy precipitation, and lush vegetation.

Leeward Side

The sheltered side of a mountain range downwind from prevailing air currents, where descending air warms and absorbs moisture.

Rain Shadow

A dry, arid area created on the leeward side of a mountain range because air loses most of its moisture on the windward side.

Climograph

A standardized chart summarizing regional climate by plotting mean monthly temperature on the left vertical axis and mean monthly precipitation on the right vertical axis.

Soil Horizons

Distinct, horizontal layers running parallel to Earth's surface that together make up a complete soil profile.

O Horizon

The most superficial soil layer composed primarily of freshly fallen organic material.

A Horizon

The topsoil layer containing abundant organic matter, soil microbes, and the majority of plant roots.

B Horizon

The subsoil layer containing minerals and clay leached from upper layers, into which deeper plant roots may extend.

C Horizon

The layer composed of weathered parent material located directly above unweathered bedrock.

Gross Primary Production

The total solar energy assimilated by photosynthetic primary producers in an ecosystem.

Net Primary Production

The total energy converted into producer tissue biomass available to consumers, calculated as $\text{NPP} = \text{GPP} - \text{Respiration}$ .

Whittaker Model

An ecological classification scheme that delineates terrestrial biomes based on average annual temperature and annual precipitation.

Drip Tips

A leaf adaptation in tropical rainforest plants featuring elongated tips that facilitate rapid water runoff to keep leaves dry.

Epiphytic Habit

A plant adaptation where non-parasitic plants grow directly on the surface of other plants or trees to access light within dense forest canopies.

Sahelanthropus tchadensis

An early hominin fossil species recognized as one of the earliest bipedal primate ancestors of modern humans, originating in African savanna habitat.

Desertification

The expansion of desert biomes into formerly non-desert lands caused by human activities like overgrazing, poor farming, and climate change.

Sclerophyllous Leaves

Hard, needle-like or leathery leaves with few stomata that reduce water loss in plants adapted to dry summer climates.

Deciduous Habit

The seasonal shedding of leaves by trees to minimize water loss or cold damage during unfavourable non-growing periods.

Underground Meristem

A growth tissue adaptation in prairie grasses situated below the soil surface, protecting plants from fire and grazing damage.

Permafrost

A layer of soil beneath the surface that remains frozen continuously year-round in tundra and polar biomes.

Tropical Rain Forests

•Store MASSIVE amounts of carbon

•Clearing/burning releases that stored carbon into atmosphere, affecting anthropogenic climate change

•Drugs from plants

Tropical Seasonal Forest/Savanna

•The fossil evidence indicates that the first bipedal primate ancestors of modern humans lived here (Sahelanthropus tchadensis)***

•This biome has been important to humans as pasture and rangeland for domestic animals for thousands of years

•Forests with pronounced wet & dry seasons

•Extreme fluctuation in precipitation

•Grasslands with scattered trees

•Trees shed leaves when water stressed

•Vegetation protected against grazers

•Fires play a role in biodiversity and nutrient turnover

Subtropical Desert

•Typical undisturbed by humans

•Thought of as “wastelands”

•Useful for only mineral extraction

•Major bands at 30^o N and 30^o S latitude

•Little to no precipitation: 

•Evaporation exceeds precipitation

Woodland/Shrubland | Mediterranean Shrubland | Chaparral

•Soils tend to be very rocky and have low fertility, therefore not highly prized for agriculture

•High human density and valuable real estate have led to development of extensive housing tracks in chaparral habitat

•Places human habitation at significant risk from the recurring fires characteristic of this biome

•Mild, wet winters; severe summer drought

•Found on every continent expect Antarctica

•Fire is an important ecological feature

•Not only adapted to fire but need for germination and growth

Temperate rain forests

•Home to some of the oldest known organisms

•Biotourism – popular destination/recreation spots

MAJOR source of timber and other wood products

•Mild winters, heavy winter rains, summer fog

•Extremely tall evergreen forests

•Not well understood why these forests are dominated by evergreens, but fossil records show that these forests are extremely old remnants of extensive forests from 70 million years ago

Biodiversity much lower than tropical rain forest

Temperate seasonal forests

•Home to many rare species of plants and animals

•Extremely popular for living: aesthetics, hiking, camping, etc.

•Less vulnerable to climate change due to the “temperate” climate

•However, more vulnerable to clearing and deforestation especially for farming bc of high-quality soils

•Also known as deciduous forests

•Hot summers, mild winters with freezing

•Rainfall abundant (650-3,000 mm) with long growing season

•Multiple forest layers: herbaceous plants on forest floor, small trees and  shrubs beneath dominant trees

•Fertile soils, biomass production can be high

•Deciduous habit

Temperate Grassland

•Known as the “bread basket of the world”

•Lush, productive grass is important for grazing

•The NA prairie soil is among the most fertile in the word

•Short grass prairies have been overgrazed and have been replaced by woody plants (mesquite and cedar)

•Also known as prairies or steppes; dominated by grasses

•Winters are cold, summers are hot

•Drier than temperate forests, but in same lat range

•Some grasslands grade into deserts

•Rich soils, used for growing crops

Boreal Forest /Taiga

•Conifers and pine trees grown here are massively economically important for lumber and paper pulp (= jobs)

•Mineral and energy resources

•Hydroelectric potential of rivers

•Tourism/recreation/cultural aspects

•Confined to Northern Hemisphere (50-70*N)

•Covers 11% of earth’s land area

•Cold and relatively dry-ish

•Below or near freezing for much of year

•Thin, acidic soils low in fertility

Arctic Tundra

•Deep history of human inhabitants and currently home to many indigenous people (Aleut and Inuit tribes of Alaska)

•Tourism and recreation

•Oil/gas/mining

•The effects of climate change are much more extreme as latitude increases

•Covers most land north of Arctic Circle

•Very high latitude

•Average temperature below freezing

•200 - 600 mm rain/year (~8 – 24 inches)

•Small plants with low net primary production

•Peat: soil containing high levels of organic matter: decomposition rate < buildup

•Permafrost: soil frozen year-round, in summer, less than 1 m of soil thaws