Ecology & Ecosystems

Ecology

A branch of the biological science that studies the interactions between an organism & its environment

Levels of Organization

Biosphere Consists of:

The lithosphere

The atmosphere

The hydrosphere

→ a terrarium

Biomes

The terrestrial part of the biosphere is divided into Biomes

→Different biomes are distinguished by their climate, their soils & the species they support

Biomes are defined by:

Moisture & Temperature

Biomes Location: Winnipeg

3 of the 11

Boreal forest, prairies, temperate forest

Aquatic Life Zones

Like a biome but in the ocean

Aquatic Life Zones Define by:

Define by temperature, nutrients. & Light

Aquatic Life Zones Richest Regions

Estuaries

Two Parts of Ecosystems

biotic & abiotic

Biotic Factors

Other species in the ecosystem

• Food Supply

• Predation

• Competition

Also has a range of tolerance

Habitat

The specific place where a species is found

Ex: Deer live in Assiniboine forest - Habitat

Niche

Where an organism is found & what it does

Ex: Deer live in Assiniboine forest, eat grass & feed coyotes

• No two species have the same Niche

  • Deer & Elk, Owl & Hawk

Humans: Generalized & Specialized

Specialized but due to technological advances we’ve gotten quite good at living all over the world

• Without 3 species of plant (wheat, barley, & corn) & 3 species of animal (cow, pig, chicken), & one mineral (iron)

  → We wouldn’t be well off

Food Chains & Webs

The transfer of energy and nutrients through a series of organisms in an ecosystem

Producers

Organisms that can convert sunlight into carbohydrates through photosynthesis, forming the base of the food chain.

Consumers

Organisms that consume producers or other consumers for energy.

Decomposers

Organisms that break down dead organic matter and release nutrients back into the ecosystem.

Omnivore

An organism that consumes both plants and animals.

Herbivore

An organism that only eats plants.

Carnivore

An organism that only eats meat.

Energy

The capacity to do work

Potential Energy

Energy stored in an object or system

• Ball on top of hill or chemical bond

• Kinetic energy is energy of motion

1st Law of Thermodynamics

Energy cannot be created or destroyed, but only changed from one form to another

2nd Law of Thermodynamics

In any energy conversion, there will be some loss of energy as heat

Nutrient Cycles

Nutrients (unlike energy) are recyclable

Biogeochemical

The cycles that move chemicals around the biosphere

Balance & Imbalance in Ecosystems

The state of equilibrium or disruption in an ecosystem.

• Lake Victoria & the Nile Perch

• Water hyacinth in Florida

Efficiency in the Food Chain

The percentage of energy transferred from one trophic level to the next in a food chain.

Carbon Cycle

The cycling of carbon through the atmosphere, living organisms, and the Earth's crust.

Stable Ecosystem

Things changed a little from day to day or month to month or in annual cycles, but generally they stayed much the same

→ Dynamic equillbrium

Dynamic Equilibrium

An ecosystem that fluctuates around a central point but maintains overall stability

Ecosystem Stability

1. The total number of living spcies is constant (or almost), year after year

2. The same species are present every year &;

3. The P of each species is roughly the same every year

Population Growth in Ecosystems

Populations of various species are controlled by many factoes, some of them biological, or biotic, & some of them not, abiotic

Population Growth: Biotic Growth Factors

• Reproductive Rate

• Adaptability

• Ability to migrate

• Competitiveness

• Food Supply

Population Growth: Abiotic Growth Factors

• Favourable light

• Favourable temperature or moisture

• Lots of others

Population Growth: Biotic Reduction Factors

• Predators

• Parasites

• Food Shortage

• Loss of Habitat

Population Growth: Abiotic Reduction Factors

• Bad Weather

• Water Shortage

• Pollution

Resisting Change: Stable Ecosystem

If an ecosystem is stable, it resists change & the system is said to have inertia

Resisting Change: Significant Change in Ecosystem

If it changed significantly & then it bounces back to something like its original state, & it is said to have resilence

Human Impact on Ecosystems

Introducing new species

• Nile Perch

• Africanized Killer Bees

Removing a species

• Kaibab Plataeu in Arizona

Introducing Parasites

• Bacillus thuringiensis (BT)