Ecology Basics
1. What is Ecology?
Definition: Ecology is the study of how living organisms interact with each other and their environment.
Levels of Organization:
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.
2. Key Concepts:
Biotic Factors: Living components (plants, animals, microorganisms).
Abiotic Factors: Non-living components (sunlight, temperature, water, soil).
Energy Flow:
Producers (autotrophs) → Primary Consumers (herbivores) → Secondary Consumers (carnivores) → Decomposers (break down dead material).
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).
Nutrient Cycles:
Carbon Cycle: Movement of carbon through living organisms, the atmosphere, and Earth.
Nitrogen Cycle: Movement of nitrogen between air, soil, and organisms.
3. Adaptations and Niches:
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).
1. Characteristics of Desert Biomes:
Climate: Low rainfall (less than 250 mm/year), extreme temperatures (hot during the day, cold at night).
Soil: Often sandy or rocky, poor in organic material but may have minerals.
Vegetation: Sparse; plants like cacti, shrubs with adaptations to store water.
Types of Deserts:
Hot Deserts: e.g., Sahara, Arabian Desert.
Cold Deserts: e.g., Gobi Desert.
2. Abiotic Factors:
Temperature: Often extreme, fluctuates between day and night.
Water: Scarce, a limiting factor in desert ecosystems.
Soil Composition: Often poor in nutrients, high in salt in some areas.
3. Adaptations of Organisms:
Plants:
Xerophytes: Plants adapted to dry environments (e.g., cacti with thick, waxy skin).
Water Storage: Succulents store water in their tissues.
Reduced Leaf Area: Reduces water loss (e.g., spines instead of leaves).
Animals:
Behavioral Adaptations: Nocturnal activity 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).
1. Characteristics of Grassland Biomes:
Climate: Moderate rainfall (25-75 cm/year), seasonal variations in temperature.
Vegetation: Dominated by grasses, few trees or large shrubs.
Types of Grasslands:
Tropical Grasslands (Savannas): Found near the equator (e.g., African savanna).
Temperate Grasslands (Prairies, Steppes): Found in mid-latitudes (e.g., North American prairies, Eurasian steppes).
2. Abiotic Factors:
Soil: Often rich and fertile, ideal for agriculture due to high organic content from decaying grass.
Fire: Naturally occurring fires play a role in maintaining grasslands by controlling tree growth and recycling nutrients.
Water: Grasslands receive more rainfall than deserts but are still prone to droughts.
3. Adaptations of Organisms:
Plants:
Deep Roots: Grasses have deep roots to access water and resist grazing.
Growth Resilience: Grasses can grow back quickly after being grazed or burned.
Animals:
Grazing Herbivores: Large mammals like bison, antelope, and zebras graze on grasses.
Predators: Carnivores like lions, wolves, and hawks hunt the herbivores.
Insects: Insects like grasshoppers and ants play a significant role in the ecosystem.
Grassland Food Web: Grasses (primary producers) → Grazing herbivores (primary consumers) → Predators (secondary consumers) → Decomposers.
4. Human Impact:
Agriculture: Grasslands are often converted for farming due to fertile soil.
Desertification: Overgrazing and climate change can degrade grasslands into desert-like conditions.
Feature | Desert | Grassland |
Rainfall | Less than 250 mm/year | 25-75 cm/year |
Temperature | Extreme (hot days, cold nights) | Moderate, seasonal fluctuations |
Vegetation | Sparse (cacti, shrubs) | Dense grasses, few trees |
Soil | Sandy, poor in nutrients | Rich, fertile |
Animal Adaptations | Water conservation, nocturnal behavior | Grazing adaptations, social groups (herds) |
Threats | Climate change, water scarcity | Overgrazing, conversion to farmland, desertification |
1. What is Ecology?
Definition: Ecology is the study of how living organisms interact with each other and their environment.
Levels of Organization:
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.
2. Key Concepts:
Biotic Factors: Living components (plants, animals, microorganisms).
Abiotic Factors: Non-living components (sunlight, temperature, water, soil).
Energy Flow:
Producers (autotrophs) → Primary Consumers (herbivores) → Secondary Consumers (carnivores) → Decomposers (break down dead material).
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).
Nutrient Cycles:
Carbon Cycle: Movement of carbon through living organisms, the atmosphere, and Earth.
Nitrogen Cycle: Movement of nitrogen between air, soil, and organisms.
3. Adaptations and Niches:
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).
1. Characteristics of Desert Biomes:
Climate: Low rainfall (less than 250 mm/year), extreme temperatures (hot during the day, cold at night).
Soil: Often sandy or rocky, poor in organic material but may have minerals.
Vegetation: Sparse; plants like cacti, shrubs with adaptations to store water.
Types of Deserts:
Hot Deserts: e.g., Sahara, Arabian Desert.
Cold Deserts: e.g., Gobi Desert.
2. Abiotic Factors:
Temperature: Often extreme, fluctuates between day and night.
Water: Scarce, a limiting factor in desert ecosystems.
Soil Composition: Often poor in nutrients, high in salt in some areas.
3. Adaptations of Organisms:
Plants:
Xerophytes: Plants adapted to dry environments (e.g., cacti with thick, waxy skin).
Water Storage: Succulents store water in their tissues.
Reduced Leaf Area: Reduces water loss (e.g., spines instead of leaves).
Animals:
Behavioral Adaptations: Nocturnal activity 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).
1. Characteristics of Grassland Biomes:
Climate: Moderate rainfall (25-75 cm/year), seasonal variations in temperature.
Vegetation: Dominated by grasses, few trees or large shrubs.
Types of Grasslands:
Tropical Grasslands (Savannas): Found near the equator (e.g., African savanna).
Temperate Grasslands (Prairies, Steppes): Found in mid-latitudes (e.g., North American prairies, Eurasian steppes).
2. Abiotic Factors:
Soil: Often rich and fertile, ideal for agriculture due to high organic content from decaying grass.
Fire: Naturally occurring fires play a role in maintaining grasslands by controlling tree growth and recycling nutrients.
Water: Grasslands receive more rainfall than deserts but are still prone to droughts.
3. Adaptations of Organisms:
Plants:
Deep Roots: Grasses have deep roots to access water and resist grazing.
Growth Resilience: Grasses can grow back quickly after being grazed or burned.
Animals:
Grazing Herbivores: Large mammals like bison, antelope, and zebras graze on grasses.
Predators: Carnivores like lions, wolves, and hawks hunt the herbivores.
Insects: Insects like grasshoppers and ants play a significant role in the ecosystem.
Grassland Food Web: Grasses (primary producers) → Grazing herbivores (primary consumers) → Predators (secondary consumers) → Decomposers.
4. Human Impact:
Agriculture: Grasslands are often converted for farming due to fertile soil.
Desertification: Overgrazing and climate change can degrade grasslands into desert-like conditions.
Feature | Desert | Grassland |
Rainfall | Less than 250 mm/year | 25-75 cm/year |
Temperature | Extreme (hot days, cold nights) | Moderate, seasonal fluctuations |
Vegetation | Sparse (cacti, shrubs) | Dense grasses, few trees |
Soil | Sandy, poor in nutrients | Rich, fertile |
Animal Adaptations | Water conservation, nocturnal behavior | Grazing adaptations, social groups (herds) |
Threats | Climate change, water scarcity | Overgrazing, conversion to farmland, desertification |
