Basic Concepts of Ecology

Página 1

Define ecology :

--> Ecology is the study of how organisms interact with one another and with their nonliving environment.

Basic terminology of ecology

Species : A group of organisms that resemble one another in appearance, behaviour, chemistry, and also genetic structure. Species is organisms that can breed with one another to produce fertile offspring under natural conditions.

Population : a group of the same species occupying the same area at the same time.

Habitat : inhabit/dwells in. Habitat is an area/ a kind of environment where an organisms normally occurs. = A place where a person or thing is most likely to be found.

Niche : Ecological niche - it describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors.

Ecosystem : A community of different population of species interacting with one another and their nonliving environment / Interactions among the organisms of the community and also the interactions between organisms and their physical environment.

Biome : Large distinctive complex of plants, animals and soil organism communities created and maintained by climate.

TUNDRA

Mostly at the lands in arctic circle, north.

Climate - cold and dry. Long harsh winters -28 to -50 celsius

Short & soggy summer = 30 days/1 month 0 to 35 Fahrenheit.

Precipitation/rainfall = 150mm - 250mm

Soil = Frozen 25-90cm down.

Slow decomposition, organic matter accumulate in deposits of peat & humus.

Species = mosses, lichens, grasses, sedges, dwarf willows & birches.

TAIGA

Largest land biome

Northern hemisphere 50-65 north latitude

Scandinavia, European Russia, Siberia, Central Alaska & Canada

Average temp -5 to 5 celsius. Extremely cold temp = -20 to -40

Long winters more than 6 months and short sumers.

Precipitation 200-600mm

Soil = low fertility, thin, acidic

Slow decomposition because of low temp & low pH. Plant litter decompose slower & rate of soil building is slow.

Nutrients = tied up in thick layer of plant litter.

Thin topsoil & when extreme cold climate, subsoil freezes permanently, several metres thick.

Species = evergreen conifers ---> spruce fir pines.

Wind pollinated trees, none produces fleshy fruits.

Página 2

TEMPERATE FORESTS (Coniferous/deciduous)

Climate = hot summer & winter is noticeable

Precipitation 650-1500mm

Species = Dense canopy of broad leaved trees, saplings & shrubs as an undergrowth

Soils are fertile & neutral/slightly acidic. Rich in organic matter & inorganic nutrients.

Herb layer ---> Shrubs > Shade-tolerant understory trees ---> Canopy

SHRUB FOREST

Mediterranean climate

30-40 latitude.

Chaparral - Western North America, Matoral - Spain, Garrigue - Mediterranean basin, Fynbos - South Africa, Mallee - Australia

Climate - Temperate env. Cool region. Cool & Moist (fall, winter & spring) Hot & dry (summers)

Dry summer ---> dense vegetation, rich in essential oil = ideal condition for frequent & intense fires

Soils = low - moderate fertility. Fragile, can occur severe soil erosion.

Adapt to drought & fire resistant.

Herbaceous plants - grown during cool & moist season & die in summer

Página 3

Temperate Grassland

WHERE ?

North America ---> Southern Canada to the Gulf of Mexic

Eurasia --> Eastern Europe to Eastern China

Southern Hemisphere --> Argentina, Uruguay, Southern

Brazil & New Zealand.

CLIMATE

Precipitation/ rainfall is moderate -- > 300 to 1000mm

It is wetter than desert

Drought occurs once in a while

Draught & high summer temp encourages fire

Winters are generally cond & summer are hots

Steppe – Central Asia

Prairie – North America

Pampas in South America

Soil

Basic or neutral

Fertile, contains lots of organic matter

Deep & dark in colour

Ideal for farming, but can be exposed to wind erosion if the

ecosystem isn’t balanced

Herbaceous Vegetation dominating the area

Savanna (Tropical Grassland)

N & S of tropical dry forests 10-20 degree of the

equator

Africa – world’s largest savanna

South america, brazil, northern Australia, Eastern Pakistan

& northwestern India.

CLIMATE

Warm all year round

2 SEASONS – Very long dry season (winter)

very wet season (summer)

Soil layers == not very permeable to water, so surface soils

is waterlogged during summer(wet season)

Intense lightning, causes fire. Fire kills young trees,

grasses survives & resprout quickly. This helps maintain the tropical

savanna -- landscape of grassland with

scattered trees

Alpine Grasslands

Geography

Mountains. North & South America, New Guinea & East

Africa.

CLIMATE :

Climate at low areas is different compared to those of high

areas/altitude.

Challenging for plant life

Low tempteratures & high incoming shortwave radiation

Desert

20% land surface in earth

All continents mostly in the Tropic of Cancer & Tropic

of Capricorn

LARGEST – Sahara Desert

DRIEST – Atacama Desert in Chile

CLIMATE :

Drought occurs during all months, some exceed 30 degrees

celsius.

Shade temp more than 56 degrees was recorded in North Africa

& Western North America

Soil

Low in organic matter --- classified as lithosols ( stone or

mineral soil.

BUT under desert shrubs often contain good amount of organic

matter

Lowland soils, poorly drained valley, high concentrations of

salts. When the soil age, they often form calcium carbonate rich hardpan

horizon = caliche

Temperate Rain Forests

Oceanic moist climates --> Western north america,

southwestern south america, Northwestern Europe, Southeastern Australia, &

South Island’s west coast of New Zealand.

CLIMATE

Precipitation / rainfall – 1500mm

Temp 4 & 12 degree celsius

Tropical Rain Forest

10 latitude N or S equator.

Southeast Asia

West Africa

South & Centra America

CLIMATE

Warm and wet/humid

25 – 27 degrees celsius

Precipitation/rainfall 2000-4000mm

SOIL

Low quality

Nutrient poor

Acidic

Thin & low of organic matter

Heavy rain leach nutrients from soil

Rapid Decomposition

Biosphere consist all of the organisms. All communities.

Hydrosphere, Lithosphere, Atmosphere = Biosphere.