Ecosystems: Components and Types

• An ecosystem includes all of plants and animals in a specific environment.
• Ecosystems can be large-scale macro-ecosystems or small-scale micro-ecosystems.
• Arthur G. Tansley, an English ecologist, first used the term ecosystem.
• Ecosystems are generally classified as terrestrial (land) or aquatic (water).

Ecosystem Components

• These are biotic: all living things
• These are abiotic: all non-living things

Biotic Ecosystem Components

• This is a description of biotic ecosystem components
• Producers are plants performing photosynthesis in terrestrial ecosystems, utilizing carbon dioxide, sunlight, and water and are known as autotrophs.
• Producers of the aquatic ecosystem are phytoplanktons that perform chemosynthesis through chemical metabolism.
• Consumers are heterotrophs that obtain energy by eating other organisms.
  • Herbivores are primary consumers eating plants.
  • Carnivores are secondary consumers eating animals.
  • Omnivores are tertiary consumers eating both plants and animals.
• Decomposers are bacteria and fungi, the janitors of nature, that return nutrients to the ecosystem by acting on dead organisms and are known as saprotrophs.
  • Bacteria is the most abundant decomposer.
  • Fungi is the fast-acting decomposers.

Specific Functions in the Ecosystem

• Plants - producers
• Animals - consumers
• Bacteria and fungi - decomposers
• Ecological niche involves the functional role of an organism in its ecosystem.
• Trophic perspective classifies plants as autotrophs, animals as heterotrophs, and bacteria/fungi as saprotrophs.

Species Classification

• Species are classified as specialist or generalist based on their niches.
  • Specialist species have narrow niches with specific adaptations and are prone to endangerment or extinction.
    • Owls, Giant pandas, woodpeckers and tiger salamanders are examples of Specialist species.
  • Generalist species have broad niches with wide tolerance and can live in different places and eat many foods.
    • Cockroaches, rats, humans, and flies are examples of generalist species.

Specialized species roles in the ecosystem.

• Native species normally live in an ecosystem.
• Immigrant species migrate or are newly introduced to an ecosystem
• Indicator species serve as early warnings of ecosystem damage.
• Keystone species play a large and disproportionately important role in an ecosystem relative to their biomass.

Abiotic Ecosystem Components

• Abiotic components include temperature, water/moisture, light, soil, wind, time, and energy.
• Abiotic components dictate organisms or species living in a particular area.

Temperature

• Temperature refers to the hotness or coldness of an area.
• Temperature affects the internal metabolism and behavior of an organism.
• Plants experience a wide temperature range because they are stationary.
  • Minimum temperature is the lowest temperature an organism can function; below that, it cannot survive.
  • Maximum temperature is the highest temperature an organism can function; above that, it can die.
  • Optimum temperature is where an organism functions best.

Temperature and Animals

• Homeotherms are warm-blooded animals using endothermy to maintain body temperature, e.g., birds and mammals.
• Poikilotherms are cold-blooded animals that control their body temperature by external means (ectothermy), e.g., invertebrates, amphibians, and reptiles.
• Heterotherms regulate body temperature by endothermy and ectothermy, depending on conditions and metabolic needs, e.g., bats, bees, and hummingbirds.
• Acclimatization involves an organism's ecological adjustment to environmental changes, especially temperature variations.

Temperature and Plants

• Plants in cold areas use insulation to survive, with thick barks and hairs as adaptive structures.
• At very low temperatures, plants may suffer from frostbite or physiological drought due to ice crystals forming.

Water

• Water is important for:
  • Germination of seeds
  • Transporting substances
  • Erosion and breaking of rocks
  • Serving as a habitat

Water and Plants

• Plants absorb water through roots and lose water through transpiration in stomata.
• Xerophytes grow in dry regions and store water in succulent tissues with examples such as cactus and acacia.
• Hydrophytes float or submerge in water, their air spaces providing adaptation, with examples such as water lilies, lettuce, and lotus.
• Halophytes grow in saline environments with succulent tissues, like marine algae, seaweeds, and mangroves.

Water and Animals

• Animals get water by drinking and lose it through respiration.
• Camels can go 8 days without drinking water and tolerate a 25-40% loss of body weight.

Light

• Light, a visible electromagnetic radiation, is the main energy source in every ecosystem.
• It's an ingredient for plant photosynthesis
• Animals use light to avoid enemies, find prey, and synthesize vitamin D.
• Shade tolerance: ability of a plant to survive and grow in shade, e.g., orchid.
• Photoperiodism: an organism's response to day lengths, e.g., breeding and migration of animals and chrysanthemum, poinsettia, and sunflower growth.

Soil

• Soil is the earth's upper crust layer, affected by plants and animals comprised of weathered rocks and humus.
• Soil forms through weathering of chemical substances and mechanical weathering of breaking down rocks.
• Soil charactertistics differ in texture, moisture, pH, structure, color, and profile

Soil Texture

• Clay: fine particles, "poorly drained soil"
• Sand: coarse particles, "hungry soil"
• Silt: medium sized particles
• Loam: mix of clay, sand, silt "fertile farmland soil"

Moisture Content

• Texture
• Rainfall
• Slope
• Rock types

pH Content

• Soil acidity and alkalinity depend on the concentration of hydrogen ions
• 1-6 is acidic, 8-14 is basic and 7 is neutral
• They can be measured by using a litmus paper, pH paper or a pH meter.
• Farmers change the soil pH for nourishment, lime is basic, granite is acidic.

Soil Structure

• Soil structure is the arrangement of soil particles to make peds.
• Peds provide a way for air and water.

Soil Color and Profile

• Color depends on the chemicals
• Grey soil, or podzol, doesn't have iron. Brown or red has iron.

Soil Profile

• Soil profile refers to the vertical section of soil with layers or horizons.
  • O (Surface or litter layer): dried or dead organisms decomposed into a humic substance
  • Horizon A: humus mixes with weathered rocks, water dissolves/carries away chemicals (leaching)
  • Horizon B: chemicals dissolved from horizon A where little humus is found
  • Horizon C: has parent rocks

Wind

• Wind is an abiotic factor that affects plants.
• Wind uproots or restricts growth and causes damage
• Wind also affects transpiration rates and is involved in pollination and seed dispersal

Time

• Time measures the duration of an event
• Food hunting and gathering
• Reproduction or finding a mate
• Locomotion

Limiting Factors

• Limiting factors are abiotic that reduces an animal's growth

Liebig's Law of Minimum

• Justus Liebig created this law in 1840.
• A plant's growth relies on the amount of food provided to it minimum.

Shelford's Law of Tolerance

• Victor Ernest Shelford created this law in 1911.
• An organism can only tolerate 1 ecological factor and a narrow range of ecological tolerance to another.
• Organisms tolerating different ecological factors can be greatly distributed around the ecosystem

Blackman's Law of Limiting Factor

• Frederick Blackman created this law in 1905.
• When a process relies on many factors, the rate that it goes is limited by the slowest factor.