Ecology and natural systems

Biotic factors

Biotic factors = Living factors

Abiotic Factors

 Abiotic factors = Non-living factors

Atmosphere

 Atmosphere: all of the gases around earth; 60 mile-thick.

Atmosphere Benefits

Mainly nitrogen (78%), oxygen (21%). Provides oxygen for respiration. Protects from UV radiation. Regulates Earth's temperature (greenhouse effect). Drives weather and climate.

Biosphere

Biosphere: all living organisms

Biosphere Benefits

• Influences atmosphere (photosynthesis, respiration).

• Essential for nutrient cycling.

• Supports biodiversity.

Geosphere

Geosphere: Earth's interior and surface

Geosphere Benefits

• Provides stable ground for life.

• Source of nutrients.

• Soil formation for plant growth.

Hydrosphere

Hydrosphere: all bodies of water

Hydrosphere Benefits

• Habitat for aquatic life.

• Nutrient transport and distribution.

• Regulates Earth's temperature.

• Drives the water cycle.

Ecosystems

• Ecosystems, made up of living and non-living things that interact with each other to survive.

Terrestrial

Terrestrial: ecosystems found on land

Aquatic

Aquatic: ecosystems found underwater

Biome

A biome is a big area of Earth with the same weather, plants, and animals; category.

Land biomes

• These are on land.

• Examples: tropical forests, deserts, grasslands, tundra.

• The type of plants and animals you find depends on the temperature, rain, and soil.

• Example: Deserts are hot and dry → cactus and lizards live there.

3. Water biomes (aquatic biomes)

• These cover water areas.

• Two main types:

  • Freshwater → lakes, rivers, ponds (no salt or very little salt)

  • Marine → oceans, coral reefs, estuaries (salty water)

What lives there depends on water depth, temperature, salt level, and light.

Latitude

Latitude = how far north or south from the equator (0° at equator, 90°N at North Pole, 90°S at South Pole)

Temperature - Latitude

Warmer at low latitudes (near equator) → sun’s rays hit directly

Cooler at high latitudes (near poles) → sun’s rays spread out

Precipitation - Latitude

Warmer air near equator holds more water → more rain

Colder air near poles holds less water → less rain

Species richness

 Number of different species in an area

• Highest near equator → warm, humid year-round → good for many species

• Lowest near poles → cooler, changing seasons → harder for species to survive

• Pattern happens on land and in water

• In oceans, water currents also affect where marine species live, so patterns can vary.

Terrestrial

• As elevation increases, temperatures become cooler and precipitation increases.

• Higher elevation equals harsher climate conditions → lower species richness.

There are different types of weather. In one place, it snows, while in another, it rains in the mountains. This creates different habitats, which leads to various types of plants and animals.

Aquatic

Aquatic ecosystems are influenced by water depth, temperature, sunlight, and dissolved oxygen, with species richness higher in warmer sunlit areas. Freshwater ecosystems have low salt, while marine ecosystems contain saltwater. Factors like water velocity, clarity, pH, and proximity to land also impact these ecosystems.

Range

• Range = area where an organism lives during its lifetime

Abiotic factors affect where organisms live, as well as its survival.

• Some abiotic factors form physical obstacles, restricting where organisms can go. Such as wildfires, mountain ranges, and floods.

Temperature - Organisms

• Organisms need certain temperatures to live

• Too hot or cold → slower metabolism, less movement, growth, reproduction

Light - Organisms

• Plants need light for photosynthesis

• Too little → not enough energy to grow

Too much → leaf damage, slower photosynthesis

Moisture

• Needed for chemical reactions, nutrient transport, and body temperature control

Other Important Abiotic Factors

Other non-living factors important for ecosystems.

Term: Soil Nutrients

Definition: The amount of nitrogen, phosphorus, and potassium in the soil.

Term: Salinity

Definition: The measure of how salty water is.

Term: pH

Definition: The measure of how acidic or basic a substance is.

Term: Dissolved Oxygen

Definition: The amount of oxygen gas dissolved in water, essential for aquatic life.

Term: Abiotic Factor Needs

Definition: Each species requires specific non-living conditions to thrive.

Term: Tolerance

Definition: The ability of an organism to survive changes in abiotic factors (like temperature or sunlight).

Term: Tolerance Range

Definition: The specific range of conditions an organism can handle for survival.

Term: Optimal Conditions

Definition: Environmental conditions where an organism has the best survival and reproduction.

Term: Stressful Conditions

Definition: Environmental conditions where survival is possible, but an organism produces few or no offspring.

Term: Extreme Conditions

Definition: Environmental conditions where an organism cannot survive.

Term: Fundamental Niche

Definition: The full range of environmental conditions an organism could potentially live in based on its tolerance ranges.

Term: Realized Niche

Definition: The actual environmental conditions an organism lives in, limited by factors like competition, predation, and resources.

Term: Ecological Niche

Definition: The role and position a species has in its environment, including its abiotic needs and interactions with other species (usually refers to realized niche).

Term: Niche Adaptation

Definition: The adaptations of an organism that allow it to live in specific environmental conditions.

Term: Specialists

Definition: Species with narrow niches and small tolerance ranges, needing specific resources and often having small geographic ranges (e.g., Kirtland's Warbler).

Term: Generalists

Definition: Species with broad niches and large tolerance ranges, able to use many resources and often having wide geographic ranges (e.g., Raccoons).

Term: Population

Definition: A group of individuals of the same species living together in the same area.

Term: Population Density

Definition: The number of individuals of a population in a specific area.

Term: Population Dispersion

Definition: How individuals within a population are spread out in their habitat.

Term: Clumped Dispersion

Definition: Individuals are grouped together (e.g., a school of fish avoiding predators).

Term: Uniform Dispersion

Definition: Individuals are spaced evenly (e.g., gannet nests in a colony).

Term: Random Dispersion

Definition: Individuals have no clear pattern of spacing (e.g., plants with wind-dispersed seeds).

Term: Population Growth and Change

Definition: Changes in a population's size due to births, deaths, immigration, and emigration.

Term: Population Growth

Definition: A population increases when the birth rate is greater than the death rate, or immigration is greater than emigration.

Term: Population Decline

Definition: A population decreases when the death rate is greater than the birth rate, or emigration is greater than immigration.

Term: Resource Limitation

Definition: Populations cannot grow indefinitely because essential resources eventually become scarce.

Term: Logistic Growth

Definition: Population growth that starts slow, grows fast, then slows down and levels off as it approaches the carrying capacity, forming an S-shaped curve.

Term: Carrying Capacity (K)

Definition: The largest number of individuals of a population that an environment can support indefinitely without degradation of that environment.

Term: Density-Independent Factors

Definition: Factors that affect population size regardless of population density (e.g., volcanoes, earthquakes, fires, floods, droughts, hurricanes).

Term: Density-Dependent Factors

Definition: Factors that become more severe as population density increases (e.g., competition for food, predators, disease, parasites, stress from overcrowding).

Term: Dynamic Carrying Capacity

Definition: The carrying capacity of an environment can increase with more resources or good conditions, or decrease due to natural disasters, pollution, or habitat destruction.

Term: Energy Flow in Ecosystems

Definition: Energy originates from the sun and flows through an ecosystem from producers to consumers to decomposers.

Term: Producers

Definition: Organisms (like plants) that produce their own food using sunlight through photosynthesis.

Term: Consumers

Definition: Organisms (like animals) that obtain energy by eating other organisms.

Term: Decomposers

Definition: Organisms (like fungi and bacteria) that break down dead organic matter, returning nutrients to the environment.

Term: 10% Energy Rule

Definition: Only about 10%10% of energy is transferred from one trophic level to the next; the rest is lost as heat.

Term: Water Cycle

Definition: The continuous movement of water between the land, water bodies, and the atmosphere.

Term: Carbon Cycle

Definition: The movement of carbon through the air, plants, animals, and soil.

Term: Nitrogen Cycle

Definition: The process by which nitrogen is converted by bacteria into forms usable by plants and animals.

Term: Cycles of Matter

Definition: The natural processes (like the water, carbon, and nitrogen cycles) that ensure nutrients are continuously supplied to ecosystems.

Term: Predation

Definition: An interaction where one organism (predator) hunts and eats another organism (prey).

Term: Competition

Definition: An interaction where organisms vie for the same limited resources (e.g., food, water, space).

Term: Mutualism

Definition: A symbiotic relationship where both interacting species benefit.

Term: Commensalism

Definition: A symbiotic relationship where one species benefits, and the other is neither harmed nor helped.

Term: Parasitism

Definition: A symbiotic relationship where one species (parasite) benefits at the expense of another species (host).

Term: Ecological Succession

Definition: The process of change in the species structure of an ecological community over time.

Term: Primary Succession

Definition: The establishment and development of an ecosystem in an area that was previously lifeless (e.g., bare rock after a volcanic eruption, leading to moss, then plants, then animals).

Term: Secondary Succession

Definition: The re-establishment of an ecosystem after a disturbance (like a fire or flood) that removes existing vegetation but leaves the soil intact.

Term: Human Impacts (Negative)

Definition: Human activities that negatively impact ecosystems, such as pollution, habitat destruction, overhunting/fishing, climate change, and the introduction of invasive species.

Term: Human Impacts (Positive)

Definition: Positive actions humans can take to help ecosystems, including protecting habitats, restoring degraded ecosystems, and reducing resource consumption.