Ecology Notes Mrs. Peters Spring 2011 Mrs. Peters Spring 2011 Living vs. Non-Living Biotic Factors: all living things in an environment Ex: Plants, Animals, Bacteria Abiotic Factors: all non-living things in an environment Ex: Rocks, Sun, Water, Air Ecosystem Interaction between abiotic and biotic factors in an environment create an ecosystem Ex: Forest, Desert, Mountains, Ocean Ecosystem Energy Flow Two types of organisms Autotrophs: produce their own energy (Producers) Ex: plants Heterotrophs: depend on others for energy (Consumers) Ex: animals Ecosystem Energy Flow Types of Heterotrophs: Herbivore: consume only plants Ex: cows, rabbits Carnivore: consume only animals Ex: Lions Omnivore: eat both plants and animals Ex: humans Ecosystem Energy Flow Decomposer: absorb decaying or dead materials Ex: mushrooms Scavenger: eats anything Ex: sea gulls Ecosystem Energy Flow Energy enters an ecosystem as sunlight, autotrophs convert sunlight to food molecules using photosynthesis Ecosystem Energy Flow Food Chain: one series of feeding relationships grass grasshopper mouse hawk Food web: all feeding relationships in an ecosystem Food Web What feeding relationships do you see? Food Web and Food Chain Create your own food web using: (arrows always point toward what is getting energy) grass, eagle, salmon, bear, berries, wheat, rabbit, algae, herring, fox, mouse Label the type of organism Indicate one food chain based on your food web Ecosystem Energy Flow Energy Pyramid: diagram that shows the amount of energy that moves from one feeding level to another in a food web Trophic Levels: a feeding step of a food web, consists of species that obtain energy in a similar manner Only 10% of energy gets transferred to the next level Energy Pyramid Use your food web to create an energy pyramid label each trophic level Interactions Types of Interactions among organisms Symbiosis Competition Predator/Prey (Predation) Interactions Symbiosis: the relationship between two organisms in which at least one benefits Ex: bird on hippos, fleas on dogs Interactions Types of Symbiosis: Commensalism Mutualism Parasitism Interactions Commensalism: one organism benefits and the other is not harmed Ex: Lichen on a tree branch Interactions Mutualism: both organisms benefit from the relationship Ex: Clown fish and sea anemone Interactions Parasitism: One organism benefits and the other is harmed, but not killed Ex: mosquito and human Interactions Using magazines provided by Mrs. Peters, find pictures to represent three of the types of interactions (each type of symbiosis counts as a different type). Label each picture with the type of interaction and explain the relationship. Interactions Competition: When different species vie or struggle over the same resource Resources are limited by supply Water, food, shelter Two species with similar needs for the same limiting resources cannot coexist in the same place Interactions Niche: the role of an organism in its environment, how it makes a living How it gets food Habitat for survival All abiotic and biotic resources Interactions Niche Example Interactions Predation: where one organism kills another for its food Organism getting the food is the predator Organism that is the food is the prey Interactions Predators and prey adapt to better survive Predators get better at catching prey Speed, agility, acute senses, weaponry, camouflage Prey get better at avoiding being caught Speed, senses, hide, mimic, smell, coloring, shell, needles, taste Interactions Predator- Prey Simulation Populations Population: all members of a species in a particular area Ways to determine population size Direct Observation: counting all organisms in an area Indirect Observation: counting signs of life and estimate Quadrants: count a number of organisms in a small area, then multiply by the total area Mark and recapture: organisms are caught, marked, released, then caught again to count number marked and number unmarked Populations Population Density: the number of individuals in a particular area Population density = # of individuals / unit area Ex: There are 20 butterflies counted in 10 m 2 20 butterflies/10m 2 = 2 butterflies/m 2 Population Changes Populations change in size when new members join or when members leave Ways populations change size: Births (+) and Deaths (-) Immigration (+) and Emigration (-) Populations Limiting Factors: environmental factors that cause a population to decrease Types of Limiting Factors: Density Dependent: depends on population size Density Independent: population size doesnt matter 1. Food and water: an environment has a limited amount of each, both are required for survival (DD) 2. Space: the amount of area a population lives in (DD) 3. Weather: temperatures, rainfall, hurricanes, and floods can change the environment and not allow survival (DI) Populations Carrying Capacity: the largest population an area can support due to limiting factors What happens when Population goes above? Populations stays below? Populations Kaibab Deer Investigation History of Human Growth Predicting Human growth Disturbances in Communities