MST-ECOLOGY.pdf

NATURE OF ECOLOGY Rio Frances G. Callores  Oikos (dwelling) logos (science) Ecology Oekologie (1866) Ernst Haekel  What is ecology? Ecology = the...

NATURE OF ECOLOGY Rio Frances G. Callores  Oikos (dwelling) logos (science) Ecology Oekologie (1866) Ernst Haekel  What is ecology? Ecology = the study of the relationships of living things with each other and their environment – It is a science of relationships. What does it mean to be alive? SO…WHAT IS A LIVING THING?? Look around the room… What’s alive? What’s not alive? What used to be alive? Levels of Organization and Hierarchy  Biosphere Biosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water. The highest level of organization Biomes  Biomes Tundra Chaparral Taiga Desert Grasslands Desert-scrub Deciduous Forest Savanna Alpine Rainforest Biomes Savanna Biome  Ecosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial)  Community-several interacting populations that inhabit a common environment and are interdependent.  Population-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter)  Organism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual. The lowest level of organization What sorts of things affect living organisms? Other living things Biotic factors Prey/food source Plants Other predators  Habitat vs Niche Niche - the role a species plays in a community (job) Habitat- the place in which an organism lives out its life(address) Example: The ecological niche of a sunflower growing in the backyard includes absorbing light, water and nutrients (for photosynthesis), providing shelter and food for other organisms (e.g. bees, ants, etc.), and giving off oxygen into the atmosphere. The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism’s “address”, and the niche is its “profession”, biologically speaking. “Address”—Soil, Ground, Worm’s etc. Niche “Profession”– Mix-up soil Roles in the ecosystem Grasses: Producer Antelope: Consumer Cheetah: Consumer Make their own food Eat plants Eat animals Termites: Decomposer Recycle dead plants animals into useful energy for plants  Habitat vs Niche A niche is determined by the tolerance limitations of an organism, or a limiting factor. – Limiting factor- any biotic or abiotic factor that restricts the existence of organisms i as specific environment.  Population Size Can be limited by Competition Natural Disaster Predation Parasitism Unusual and disease weather DENSITY-DEPENDENT LIMITING FACTORS Density-dependent limiting factors operate strongly only when population density reaches a certain level. These factors do not affect small, scattered populations as much. Examples: competition, predation, herbivory, parasitism, disease, and stress from overcrowding, humans as predators. DENSITY-INDEPENDENT LIMITING FACTORS Density-independent limiting factors affect all populations in similar ways, regardless of population size and density. Examples: unusual weather such as hurricanes, droughts, or floods, and natural disasters such as wildfires, can act as density-independent limiting factors. Tolerance Range and Optimum Range