5.1.1 - Define habitat, species, population, community,

ecosystem, ecology.

G.1.1 - Factors affecting the distribution of plant species

G.1.2 - Factors affecting the distribution of animal

species

Ecology is the scientific study of the interactions between organisms & their environment.

Ecology from the Greek words: oikos (house) andlogos (study).

Interactions determine the distribution and abundance of life.

Darwin proposed that environmental factors interacting with variations within populations caused evolutionary change.

Understand ecology to understand evolution.

Species: a group of organisms that can interbreed and produce fertile offspring

From Latin for “kind”; the basic unit of evolution:What kind (species) of animal or plant is that?

Each species has at least one characteristic that sets it apart from other members of the genus & is

constant.

Members of a species mate & produce fertile offspring.Most hybrid matings are sterile: donkey X horse → burro.

New genera develop when species build up many changes.

Habitat: the specific environment in which a species normally lives, or the physical location of an organism

Each habitat has specific biotic and abiotic factors.Biotic factors: the living componentsAbiotic factors: non-living chemical and physical

factors such as temperature, light, water, & nutrients

Population: a group of organisms of the same species that lives in the same place at the same time

(This definition is very precise.)

Community: a group of populations living and inter-acting with each other in the same area

Everglades community

Coral Reef community

Ecosystem: a self-sustaining collection of organisms & their physical environment (community + habitat)

Examples of ecosystems: (specific locations)

The Everglades The Great Barrier Reef The Sonora Desert

Many factors affect where life can exist.Abiotic factors – non-living requirements

Water, temperature, pH, sunlight, shelter (cave), etc.

Biotic factors – living influences Food supply (prey or vegetation),

predators, shelter (within living things like trees or a host species)

Ex: a bluebird eats seeds and worms, nests in a

tree, but also needs water and oxygen.

Temperature: From cold tundra …

… to tropical rain forests

(short growing season)

Water: a requirement for life as we know it From aquatic swamps …

… to terrestrial forests and deserts

Water: a requirement for life as we know it The rain shadow effect:

Las Vegas,Nevada

California

Sunlight: Global climate patterns are determined by sunlight & the planet's movement in space. Produce: temperature variations,

air movement,

water evaporation

Seasonality

Sunlight: required by autotrophic plants for photosynthesis Too little light

leads to reduced or no growth.

Soil pH: hydrogen concentration in the soil affects the ability of plant roots to take up certain minerals,

can also affect beneficial fungi (mycorrhizae) →→ & bacteria

Limestone soils are basic

(high pH = low acidity). High sulfur soils are

acidic.

Salinity: high salinity (excess Na+ or K+) interferes with uptake of other metal ions needed by the plant.

Some plants can excrete excess salt.

Mineral nutrients: supply needs for growth (nitrogen, phosphorus, potassium, calcium, sulfur, etc.). Deficiencies produce disease; excess leads to toxicity.

Boron toxicity Magnesium deficiency

As with plants: Example – reptiles (snake, lizard)

Temperature Cold-blooded – not in tundra (slow to acclimate)

Water Need less – common in deserts

(uric acid waste is a paste)

Food Need less – reduces predation (need 1/10 of the calories of a

warm-blooded animal of the

same size)

Territory: a bounded physical space that an animal de-fends against encroachment, usually by members of its own species.Reduces competition

for foodfor shelterfor matesfor nesting

Breeding sites: locations where animals gather to mateExamples: Alligators need to excavate pits.Many bird species migrate to particular

locations.Swallows return to San Juan Capistrano in

California.Monarch butterflies gather

in forests in Mexico.

Water is denser than air and contains dissolved material.

Water chemistry: salty or fresh? dissolved oxygen?

Depth: water pressure and temperature

Light: photosynthetic plankton are the base of the food chain.Definitions:Definitions:

Photic: light is presentPhotic: light is present Aphotic : continuously darkAphotic : continuously dark Benthic: along the bottomBenthic: along the bottom Pelagic: not close to bottom Pelagic: not close to bottom nor near the shorenor near the shore

G.2.9 – Distinguish between biome and biosphere

G.2.11 - Outline the characteristics of six major biomes

G.2.10 - Explain how rainfall and temperature affect

the distribution of biomes.

Biosphere: the entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.

An envelope perhaps 10 km above & below the surface.

Biome: any of the world’s major ecosystemsClassified according to the predominant

vegetationCharacterized by adaptations of organisms to

environmentExamples: rainforest, grassland, savanna, etc.

Tropical rainforests - close to equator (warm, maximum sunlight), ~100" of rain/year.Contain half of all land-dwelling species. Infertile soils, but

nutrients build up in lush forests.

Soil nutrients are soon leached when forest is cut (slash & burn)

Provide a large percent- tage of Earth’s O2.Ex: Amazon in Brazil, equatorial Africa, Asia.

Savannas: hot climate (near the tropics), distinct wet & long dry seasons; 36 - 60" of rain/year.Open grassy landscape with widely spaced trees.Huge herds of grazing mammals

with a few predators. Fire is important abiotic factor.Ex: Africa - zebras, gazelles,

lions, cheetahs, rhinos.Coastal South Florida also fits in this category.

Deserts: generally very hot & dry: < 10" of rain/year.Water determines characteristics of life.Sparse vegetation: cacti & succulents. Adaptive features on plants save water:

waxy leaves, thorns.Many animals are nocturnal to avoid heat:

reptiles are more common (water-tight skin & eggs)

Ex: Australia, Sahara, Mongolia, North America

Temperate grasslands: exhibit seasonal drought, occasionalfires; usually used now for grazing and agriculture.Dry, hot summers & cold winters; 4 - 24" of

rain/year.Deep soils build up over thousands of years.Populated by grazing herds of mammals like

bison, elk, & wild horses.Ex: Prairie covered the US

interior through 1870; also found on the steppes

of Russia and the pampasof Argentina.

Temperate deciduous forests: contain dense stands of trees & have very cold winters and hot summers. The trees lose leaves and go dormant in winter. 30 - 100" of rain/year.Trees include maple, oak,

hickory, beech.Animals like bears, wolves,

deer, beavers, raccoons. Ex: E.& S. United States,

N. & E. Europe, E. China.

Coniferous forests: the largest terrestrial biome on earth.Cool, short summers and long, cold winters.8 - 24" precipitation/year (significant snow).Cold, wet climate ideal for dense stands of

conifers (trees with needles: pines, firs, etc) but little diversity.

Large mammals like moose, elk, bears, lynxes, wolves.

Ex: Canada, Siberia, S. Argentina.

Tundra: low-growing plants - long cold winters and cool short summers with little precipitation (10" /year).1/5 of Earth’s surface, between conif. forest &

frozen ice.Ground is permanently frozen (permafrost) below 3

feet; therefore, trees are stunted.Short growing season –

mass flowering. Land of sedges, grasses,

mosses; foxes, owls, caribou (reindeer).

Ex: Arctic (Alaska & Arctic Circle) & alpine(high mountains).

Ultimately, the sun provides the energy to warm the planet and evaporate the water that produces rain.

Water moderates temperatures; areas near lakes and oceans warm slower.