Biology 20: Unit B- Ecosystems & Population Change: Topic 1

Ecosystems and Diversity

Ecosystem

A community of living organisms and the nonliving components of their environment

Community

An interacting group of populations of different species within a given area

Population

A group of individuals of the same species living in a specific area

Individual

Single organisms within an ecosystem

Species

Organisms that can breed w/ each other + produce fertile offspring

Population

A group of individuals of the same species living in a specific area @ the same time

Range

The geographical area in which a species of population is found

Habitats

Areas with specific biotic and abiotic factors in which organisms are adapted to survive and reproduce (behavioural, physiological, physical)

Populations can be impacted by:

Biotic Potential

The maximum number of offspring that a species could produce if resources were unlimited

What makes biotic potential limited?

Limiting Factors

Conditions which determine the size and distribution of populations

Abiotic Limiting Factors

Nutrients, Soil, Water, Sunlight, Temperature, Oxygen

Biotic Limiting Factors

Food, Mates, Disease, Competition

Limits of Tolerance

The minimum and maximum ranges of environmental conditions—such as temperature, pH, or salinity— in which an organism can survive, grow, and reproduce

Law of the Minimum

The resource in the least supply is the one that limits growth

Law of Tolerance

An organism can survive within a particular range of an abiotic factor.

Interspecific Competition

Competition between members of different species

Intraspecific Competition

Competition between members of the same species

Density Independent Factors

A factor that affects members of a population regardless of population density

Example of Density Independent Factors

Flood, fire, pesticides, destruction of habitat

Density Dependent Factors

A factor in an ecosystem that effects members of a population because of the population density

Example of Density Dependent Factors

Food shortage, competition for mates, disease, increased predation

Community of Organisms

The collection of all the populations of all the species in an ecosystem or habitat

Ecological Niche

Role that a species plays in a community & the total range of biotic and abiotic factors required for its survival

An organism's niche includes:

Habitat, place in the food web (what it eats, what eats it), breeding area, time of day it is most active

Many species can share the same habitat if:

They have different niches

Ecotones

A transition area between ecosystems that contains species from both bordering ecosystems; usually more biodiverse than its bordering ecosystems/

Community Ecologists:

Study the interactions among members of different populations

Ecosystem Ecologist:

Studies how all of the biotic and abiotic factors in a given area interact to shape an ecosystem

Factors Affecting Terrestrial Ecosystems:

soil, available water, temperature, sunlight

Soil

Can be viewed as a series of layers, each identified by its distinct colour and texture.

As you move deeper downward into the soil:

Less organic material can be detected

Available Water

Amount of available water is determined by the amount and type of precipitation.

Available water also depends on:

How long water sits on top of the soil, as well as underneath the soil

Groundwater

Water held underground in the soil

Water Table

The boundary between the saturated layer and the unsaturated soil

A Thin Water Table:

Will cause the area to be marshy or swampy

Leaching

Removal of dissolved materials from soil by water moving downwards

At cooler temps, it takes water ______ to evaporate

longer

Grasses that grow in grassland biomes have expansive root systems because:

They are adapted to harsh environmental conditions. They use their roots to reach the deep soil layers. Having large roots like this also helps insulate them and help regrow grasses in the spring

Ecosystems within any geographic region can also receive different amounts of sunlight:

An area that is shaded by a large outcrop of rock will support a different ecosystem than an area closeby but in full sunlight

Aquatic Ecosystems will have ____ dissolved oxygen when the water is ____.

More, Cold

Organisms that live in __________ ecosystems can ______ survive in marine ecosystems, and vice versa

Freshwater, Seldom

Ecosystems near the surface of a body of water will:

Have more light exposure and experience greater temperature changes

Water becomes ____ and ____ dense until around __°C

More, More, 4°C

After 4°C, it becomes ____ dense, allowing ice to _____ on top of the cold water

Less, Float

The lowest layer of a lake is often at:

4°C

Epilimnion

The topmost layer of water. 0°C in winter.

Water continuously cycles in the Epilimnion because:

Wind

Thermocline

The layer just below the epilimnion in which there is only a little bit of mixing. Sudden drop in water temp.

Hypolimnion

Little or no mixing, depleted oxygen, most dense part of the lake, approx 4°C in winter

Spring & Fall Turnovers:

Cycle the water + help replenish the oxygen levels

Vertical Stratification

The deeper you go in an aquatic ecosystem, the less diversity you generally find

Littoral Zone

Area from shore to where no more plants grow in the lake bottom. Most productive part of the lake.

Littoral Zone Characteristics

Shallow, lots of light, rooted and floating plants flourish

Limnetic Area

Area where there is open water and sufficient sunlight for photosynthesis to occur

Limnetic Area Characteristics

Well lit, open surface water, occupied by phytoplankton & other producers that support the ecosystem

Profundal Zone

Area in which no photosynthesis can occur (below limnetic)

Profundal Zone Characteristics

Deep water with little light or oxygen, (NO photosynthesis), occupied by bottom dwellers and fish adapted to cool, dark waters.

Benthic Zone

Bottom of the lake, little to no oxygen or sunlight

Benthic Zone Characteristics

Bottom of lake, occupied by organisms adapted to low oxygen levels

The only source of nutrients in the profundal zone:

is dead plants and animals that fall from the limnetic zone

Detritus

Dead organic matter

Oligotrophic Lakes

Typically deep & cold, low nutrient levels which limits the number of producers and other organisms, water is often very clear. Eg. Upper + Lower Kananaskis Lakes

Eutrophic Lakes

Typically shallow and warm, nutrient levels high, many photosynthetic organisms, water is often murky. Eg Flyingshot Lake

How Oligotrophic lakes become eutrophic:

More and more detritus fall into the lake over time

Eutrophic lakes become increasingly shallow:

Eventually filling in and becoming dry land

Eutrophication

A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae

Diversity is _________ correlated with the _______.

Positively, Equator

Biome

A large geographical region with a specific climate, and the abiotic & biotic factors that exist in that climate

Taiga (Boreal Forest) Biome

Dominated by coniferous (trees with cones, needles) trees

Animals in Taiga Biome

Red/Flying Squirrels, moose, voles, white

Taiga is a mosaic of different ecosystems

True

Muskeg

Cooler climate, permafrost layer, slow decomposition, boggy or swampy in summer

Muskeg Plants

Shorter with expansive, fibrous root systems

Muskeg Organisms

Lichens, mosses, tall grasses, small shrubs, mosquitoes, caribou

Permafrost Layer

Layer of soil that is permanently frozen subsoil

Grassland Biome

Rich soil (most fertile in the world), less biodiversity than taiga

Organisms of Grassland Biome

Rough fescue, wheat grass, spear grass, deer, squirrel, rabbits, etc

deciduous forest

edge of grassland, just before taiga, near rivers, trees grow faster, need less water than conifers

Archaea

Bacteria

Eukarya

Kingdom Protista

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

binomial nomenclature

Classification system in which each species is assigned a two part name

The first part of any scientific name is called the genus

The first letter is always capitalized and can be written alone

The second part is called the species

Is never used alone