Ecology Basics

Ecology

The study of how living organisms interact with each other and their environment.

Individual

A single organism.

Population

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

Community

Different populations interacting in an area.

Ecosystem

A community and its physical environment (biotic + abiotic factors).

Biome

Large ecosystems defined by climate and dominant vegetation (e.g., desert, grassland).

Biosphere

All ecosystems on Earth.

Biotic Factors

Living components (plants, animals, microorganisms).

Abiotic Factors

Non-living components

Energy Flow

The transfer of energy through the trophic pyramid

Food Chains and Webs

Represent the flow of energy and nutrients through trophic levels.

Trophic Levels

Each step in the food chain (primary producers, consumers, decomposers).

Carbon Cycle

Movement of carbon through living organisms, the atmosphere, and the biosphere.

Nitrogen Cycle

Movement of nitrogen between air, soil, and organisms.

Adaptation

Traits that improve an organism’s ability to survive and reproduce.

Niche

The role or function an organism has in an ecosystem (habitat, diet, behavior).

Desert Biomes

Characterized by low rainfall, extreme temperatures, and sparse vegetation.

Hot Deserts

Deserts like the Sahara and Arabian Desert.

Cold Deserts

Deserts like the Gobi Desert.

Temperature in Deserts

Often extreme, fluctuates between day and night.

Water in Deserts

Scarce, a limiting factor in desert ecosystems.

Soil Composition in Deserts

Often poor in nutrients, high in salt in some areas.

Xerophytes

Plants adapted to dry environments (e.g., cacti).

Where do plants store water?

Succulents store water in their tissues.

Reduced Leaf Area

Adaptation to reduce water loss (e.g., spines instead of leaves).

Nocturnal Activity

Behavioral adaptation of animals to avoid daytime heat.

Physiological Adaptations

Efficient kidneys to conserve water, ability to store fat (e.g., camels).

Desert Food Web

Primary producers (cacti, shrubs) → Primary consumers (insects, rodents) → Secondary consumers (lizards, snakes).

Grassland Biomes

Characterized by moderate rainfall and dominated by grasses.

Tropical Grasslands

Found near the equator (e.g., African savanna).

Temperate Grasslands

Found in mid-latitudes (e.g., North American prairies).

Soil in Grasslands

Often rich and fertile, ideal for agriculture.

Fire in Grasslands

Naturally occurring fires maintain grasslands by controlling tree growth.

Water in Grasslands

Receives more rainfall than deserts but is still prone to droughts.

Deep Roots

Adaptation of grasses to access water and resist grazing.

Growth Resilience

Grasses can grow back quickly after being grazed or burned.

Grazing Herbivores

Large mammals like bison and zebras that graze on grasses.

Predators in Grasslands

Carnivores like lions and wolves that hunt herbivores.

Insects in Grasslands

Play a significant role in the ecosystem (e.g., grasshoppers).

Grassland Food Web

Grasses (primary producers) → Grazing herbivores (primary consumers) → Predators (secondary consumers) → Decomposers.

Agriculture

Grasslands are often converted for farming due to fertile soil.

Desertification

Overgrazing and climate change can degrade grasslands into desert-like conditions.

Rainfall in Deserts

Less than 250 mm/year.

Rainfall in Grasslands

25-75 cm/year.

Temperature in Grasslands

Moderate, with seasonal fluctuations.

Vegetation in Deserts

Sparse (cacti, shrubs).

Vegetation in Grasslands

Dense grasses, few trees.

Soil in Deserts

Sandy, poor in nutrients.

Soil in Grasslands

Rich, fertile.

Desert adaptations

Water conservation and nocturnal behavior.

Animal Adaptations in Grasslands

Grazing adaptations and social groups (herds).

Threats to Deserts

Climate change and water scarcity.

Threats to Grasslands

Overgrazing, conversion to farmland, and desertification.