Ecosystem, Habitat, and Niche

Ecosystem, Habitat, and Niche

• An ecosystem is the interaction between all biotic (living) and abiotic (non-living) factors within a specific geographic area.
• Ecosystems are dynamic and vary greatly in size, location, and diversity.
• A habitat is an organism's natural home within an ecosystem, providing food, water, shelter, and living space.
• Habitats are suitable dwellings for different groups of organisms, such as forests, deserts, grasslands, or marine environments.
• A niche is the unique role an organism plays within its ecosystem or the specific conditions it utilizes.
• Niches relate to how an organism obtains essentials like food, water, and shelter.
• Different species typically occupy different niches within an ecosystem, minimizing competition for resources.

Ecosystem vs. Habitat vs. Niche

• A habitat is simply where an animal or organism lives.
• An ecosystem accounts for the interactions of living organisms with each other and their environment.
• Ecosystems can encompass multiple habitats or be a small part of one.
• A niche is an organism's unique role or job within its ecosystem.

The Serengeti-Mara Ecosystem

• The Serengeti-Mara is an open, wooded grassland savanna in east-central Africa (Tanzania and Kenya).
• Its climate is seasonally tropical, with temperatures from 15°C (59°F) to 27°C (81°F).
• It experiences a dry season for most of the year, with rains from March to May and November to December, totaling 21-41 inches depending on location.
• The soil is volcanic ash-based, ideal for supporting various grasses.
• Fire maintains healthy, nutrient-rich grasslands.
• Animals in the Serengeti-Mara each have a specific niche.
• Each species possesses specialized needs for food, water, space, and shelter, along with the capabilities to acquire them.

Animal Niche

• All organisms need a habitat that provides for their survival.
• Within any habitat, each species interacts in its unique way, defining its niche.
• Species in an ecosystem typically do not share niches.
• Organisms with identical needs will compete, potentially leading to one species dying off or adapting.
• Healthy ecosystems have niches that replenish or make way for others.
• The niche an animal occupies depends on its living habits, including how, what, when, and where it eats, shelters, raises young, and finds water.
• Herbivores on the Serengeti have specific food preferences, such as wildebeests eating short grasses, while zebras, gazelles, and antelopes prefer herbs, shrubs, leaves, or long grasses.
• Giraffes can access food others cannot reach.
• Predators on the Serengeti also have their own niches.
• Lions hunt larger prey like wildebeest, while cheetahs hunt smaller, faster prey like antelope or gazelles.
• Herons and egrets coexist by feeding at slightly different depths in the water and breeding at different times.
• Night herons are most active in the evening.

Population Density

• A population is a group of organisms of the same species living in an area.
• Population density is the number of species within a specific area size.
• Factors such as disease, competition for resources, predation, and environmental degradation are density-dependent.
• Extreme weather, volcanic eruptions, hurricanes, drought, seasonal changes, fire, and pollution are examples of density-independent factors.