Ecology Notes

2012

Ecology:

The study of interactions between organisms and their

environment

Levels of Organization

BiosphereAll parts

of the planet that

contain life

BiomeGroup of

ecosystems with the same climate and communities

EcosystemLiving (biotic) and non-living (abiotic) aspects that interact

in a given area

CommunityDifferent population that live

and interact in

a given area.

PopulationGroup of

organisms of the same

species that live in the

same area and compete with each other for

resources

OrganismOne

individual of a

species

Factors in the Environment

Biotic Factors: Any living part of the environment

Examples: bacteria, animals, plants, insects

Abiotic Factors: Any non- living part of the environment

Examples: hours of sunlight, type of soil, rainfall

Niche• an organisms job in the environment

Niche

Niche

• Where an organism lives

African Elephant

Great Black-backed gulls

Habitat

Biomes of the world

Tundra 1/3

• Arctic Tundracold year round, -34o to 12oCPermafrost – ground never thaws out

dry, 12 to 20 cm per year

• Alpine Tundra• long, cold winters with short, cool summers• a little rain, lots of snow• Mountainous – high altitude with no trees

Tundra 2/3

• Location: northern N. America, Asia and Europe, polar ice caps

• Climate-40˚C to 18˚C

15-25cm or less annual rain

• Unique Characteristics• Coldest biome• Means treeless• Low biotic diversity

Tundra 3/3

•Animalssnowy owl, caribou, arctic fox,

lemmings and small rodentsArctic: (N) polar bears, seals, insects,

and mites (S) penguins

•Plantsground-hugging like mosses, lichens, sedges, and short

grasses• Arctic: (N) mosses and lichens

Desert 1/3

• Hot/Dry: Am. West, Central and South Am., Africa, Australia, Mexico, Middle East

• Semi Arid: West Coast of California,

Russian steppes, Southern Europe, North Asia

• Coastal: Chile

Cold: Greenland

Desert 2/3

• Makes up 1/5 of Earth’s surface• Plants and Animals are well adapted to the

dry environment• Climate: Hot days (49oC) followed by cold

nights (20oC)• Ann Precipitation: dry, less than 25 cm per

year

Desert 3/3

• Unique Characteristics• Variable temperatures• Soils rich in minerals but poor in organic

material

• Animals• Mountain lions, gray foxes, bobcats, antelopes,

kangaroo, bats, owls, hawks, and roadrunners, ants, beetles, rattlesnakes and lizards

• Plants• Cacti, creosote bush, other plants with short growing cycles

Grassland• Covers ½ of Africa (5 million mi2)• Examples– Tropical Savanna (E. Africa, S. Brazil, N. Australia)

– Temperate (C. Asia, N. America, Australia, C. Europe)

Tropical/Savanna Climate: (20o to 25oC)

-warm year round

-seasonal rainfall -rich soil

Ann. Precipitation: 50 to 125 cm/yearAnimals: lions, tigers, leopards, cheetahs,

elephants, giraffes, zebras, termites, pelicans, monitor lizards

Plants: tall grass (savanna), tall deciduous trees, orchids, bromeliads (tropical)

Temperate

• Climate: winter (-4oC),

spring, summer (38oC), fall -fertile soils

• Ann. Precipitation: 50 to 90 cm/year rain and snow

• Animals coyotes, badgers, wolves, grizzly bears,

rabbits, bison, owls, snakes, grasshoppers

• Plants lush, perennial grasses and herbs

Tropical Rainforest 1/2

• Greatest species diversity• Found in areas near the equator, hot

and wet yr round• Thin, nutrient-poor soils• Climate: warm year round

(20o to 25oC)

• Ann Precipitation: – 200 + cm/year

Tropical Rainforest 2/2

• Animals

sloths, jaguars, anteaters, monkeys, parrots, butterflies, piranhas, boa constrictors, anacondas

• Plantsferns, large woody vines, orchids, bromeliads, climbing plants, broad-leaved evergreen trees

Temperate Forest (Deciduous)

• 4 seasons, fertile soil• Climate: changes dramatically with the seasons (-30o to 30oC)• Ann. Precipitation: 75 to 150cm/year

rain and snow• Animals: deer, black bear, squirrels,

raccoons, skunks, turkeys• Plants: deciduous trees, some conifers, flowering

shrubs, herbs, ground layer of mosses and ferns• Location: E. U.S., SE Canada, most of Europe,

parts of Japan, China, and Australia

Taiga(Boreal)

• Low temperatures• High humidity• N. Am., Asia, N. Europe• Acidic, nutrient-poor soil• Climate: short cool summers, long cold

winters• Ann. Precipitation: 40 to 100 cm/year,

mostly snow• Key Trait: Evergreen Trees

Aquatic

• Freshwater – “sweet” water, able to drink•Marine – salt water, unable to drink, covers 3/4 of Earth’s surface

Freshwater

• Standing Water– Lakes and Ponds

• Flowing Water– Rivers and Streams

Marine (ocean)Photic Zone = Light penetrates

Intertidal Zone-exposed to tides and air-snails, sea stars, sea urchins, seaweed,

Coastal Ocean-plankton, kelp forests, sea otters, seals, whales, variety of fish

Aphotic Zone = no light• Open Ocean• Ocean trench

• Chemosynthetic autotrophs are only producers

that survive

Coral Reef

Warm, shallow, water with diverse environments

Estuaries Places where fresh water and salt water meet and mix

Ecological Succession

Succession

• Changes that occur in a community over time

Primary Succession

New, bare land with no soil

The first species to exist in the environment are the

Pioneer species

The ecosystem will continue to develop until a climax

community has been reached

A climax community is a mature, stable community

Secondary Succession

Occurs when there is a disturbance in the community

(Examples follow)

Natural Disasters

Animals

Abandonment

Biotic Factors

Flow of Energy 0.1%

1.0%

10%

100%

Producers=

Autotrophs

Consumers = Heterotrophs

Herbivores

Carnivore

Omnivore

Humans are Omnivores

Detritivore

Decomposer

Food Chains are a “unidirectional” flow of energy

Each step in a food chain is called a trophic level

Food Webs are linked food chains within an ecosystem

Abiotic Factors

Sun

Source of all energy in an ecosystem

Biogeochemical Cycles

Connects the biological, geological, and chemical aspects of the biosphere

Water Cycle

Evaporation- land (liquid) to air (gas)Transpiration – plants (liquid) to air (gas)Condensation – air (gas) to liquid dropletsPrecipitation – falls from sky

Carbon Cycle

Biological Processes

Photosynthesis – carbon dioxide in oxygen outRespiration – oxygen in carbon dioxide outDecomposition – carbon released into environment

Geochemical ProcessesErosion – movement of geological materials (like carbon)Volcanic Activity – volcanoes release gases (including carbon)

BiogeochemicalBurial/Decomposition – fertilizes (puts carbon into) the land and creates fossil (carbon based) fuels

Human ActionsMining – releases carbon from groundDeforestation – cutting/burning trees and releasing their carbonBurning Fossil Fuels – releases carbon into the air

Nitrogen Cycle

Nitrogen is needed to produce amino acids to build proteins

Nitrogen makes up 78% of Earth’s atmosphere

Most nitrogen is in an unusable form and must be “fixed” by Legumes (bean type) plants and/or bacteria in order to enter into the cycle

Phosphorus CycleMajor component of nucleic acids

Not found in the atmosphere, only in the land

Mostly absorbed by plants and then cycled through the ecosystems through food webs

Symbiotic Relationships

Symbiosis is a close relationship between two organisms

Predation: one organism captures and feeds on another

Parasitism: One organism lives on/in another causing it

harm

Commensalism: one organism benefits, the other is neither helped

nor harmed

Mutualism: both organisms benefit

Competition: struggle for resources

Scavenging: Feed off dead/decaying

organisms

PopulationsGroup of organisms of the same

species in same area

Characteristics of a Population

1. Geographic Distribution: area inhabited by a population (range)

2. Population Density: # of individuals per unit area

3. Growth Rate: change in size of a population (+/-)

Population Growth is Affected by:

1. Birth Rate

2. Death Rate

3. Immigration/Emigration

Types of Population Growth

1. Exponential Growth• Individuals reproduce at a constant rate• Under ideal conditions with unlimited resources,

populations will grow without limit• J-shaped curve

2. Logistic Growth-Occurs when population’s growth slows/stops

following a period of exponential growth-Ceases once carrying capacity is reached

Limiting Factors

1. Density Dependent• Limits population growth based on population

size• Example: disease, competition, stress, predation

2. Density Independent• Limits growth regardless of population size• Example: temperature, extreme weather, floods,

drought, natural disaster, habitat destruction