KEY CONCEPT Ecology is the study of the relationships among organisms and their environment.
Ecologists study environments at different levels of organization. Ecology is the study of the interactions among living things, and between living things and their surroundings. Fig. Salmon are a primary food source for many species, including grizzly bears. If salmon disappeared, species dependent on them would also suffer.
An organism is an individual living thing, such as an alligator.
A population is a group of the same species that lives in one area. Organism
A community is a group of different species that live together in one area. Population Organism
An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area. Ecosystem Community Population Organism
Biome A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there. Ecosystem Community Population Organism
Observation is the act of carefully watching something over time. Ecological research methods include observation, experimentation, and modeling. Observation is the act of carefully watching something over time. Observations of populations can be done by visual surveys. Direct surveys for easy to spot species employ binoculars or scopes. Indirect surveys are used for species that are difficult to track and include looking for other signs of their presence. Fig. Much of the data gathered by ecologists results from long hours of observation in the field. This ecologist is using radio telemetry to track coyotes.
Experiments are performed in the lab or in the field. Lab experiments give researchers more control. Lab experiments are not reflective of the complex interactions in nature. Field experiments give a more accurate picture of natural interactions. Field experiments may not help determine actual cause and effect.
KEY CONCEPT Every ecosystem includes both living and nonliving factors.
A Brief Review from August: Biodiversity is the assortment, or variety, of living things in an ecosystem. Biodiversity increases as you travel from the poles to the equator.
Biotic factors are living things. plants animals fungi bacteria
moisture temperature wind sunlight soil Abiotic factors are nonliving things. moisture temperature wind sunlight soil
A keystone species is a species that has an unusually large effect on its ecosystem.
Keystone species form and maintain a complex web of life. creation of wetland ecosystem increased waterfowl Population increased fish population nesting sites for birds keystone species
Every organism has a habitat and a niche.
A habitat differs from a niche. A habitat is all aspects of the area in which an organism lives. This includes all biotic and abiotic factors
A habitat differs from a niche. An ecological niche is The role and position a species has in its environment How it meets its needs for food and shelter How it reproduces Its behavior All its interactions with the biotic and abiotic factors of its environment
Example: The niche of black bears Ecological role: Helps carry seeds of berries (in their digestive systems) and expels them, allowing the berries to grow Finds shelter in the forest Feeds on nuts, berries, insects, and small animals Fed on by blood-sucking insects and parasites
Resource availability gives structure to a community. Species can share habitats and resources. This leads to competition
Two species can NOT share the same niche This is known as competitive exclusion Competitive exclusion has different outcomes. One species is better suited to the niche and the other will either be pushed out or become extinct. The niche will be divided. The two species will further diverge
Ecological equivalents are species that occupy similar niches but live in different geographical regions. Madagascar South America