Ecology Terms

• Succession- natural, gradual changes in the types of species tha live in an area; can be primary or secondary
• Primary Succession- begins in a place without any soil or plants, and is dominated by pioneer species
• Primary Succession Examples: sias of volcanoes, landslide, flooding
• Primary Succesion Step 1- starts with pioneer species, living things (such as lichens) that do not need soil to survive
• When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil.
• Organic Matter- living or dead organisms
• Primary Succession Step 2- simple plants (e.g. mosses, weeds, ferns) can grow in the new soil
• The simple plants die, adding more organic matter to the soil.
• Primary Succession Step 3- the soil layer thickens, and grasses, wildflowers, and other plants begin to take over. Later, when they die, they add nutrients to the soil..
• Primary Succession Step 4- shrubs and trees can now survive. Insects, small birds, and mammals begin moving in.
• Climax Community- a community that is the result of succession and is the most stable community supporting biodiversity.
• Secondary Succession- occurs on land where there was once vegetation but has been destroyed by fire, flood, or human activity.
• Secondary Succession Step 1- The first step in secondary succession is the same as primary succession - colonization by bacteria and fungi.
• Secondary Succession Step 2- Simple plants such as mosses, lichens, and herbs are able to grow because the soil contains some nutrients from the previous plant life.
• Secondary Succession- begins in a place that already has soil and once the home of living organisms
• Secondary successions occur faster and has different pioneer species than primary successions (e.g. after a forest fire)
• Pond Succession- a series of stages in which a pond develops from a small, shallow pool to a larger, deeper pool.
• Pond Succession- pond turns into a terrestrial landscape.
• Population- group of organisms of the same species living in the same area at the same time (given geographic area).
• Advantages of a Population: ease of reproduction, finding food, protection
• Disadvantages of a population: human influences, diseases transition (faster and easier), competition and consumption of resources, predation
• Dispersion- the pattern of spacing of a population in a given area
• Clumped Dispersion- the distribution of individuals is not evenly distributed throughout the population (e.g. bees).
• Uniform Dispersion- individuals are equally spaced apart from each other, and the same distance from the center of the population (e.g. territorial animals).
• Random Dispersion- the random distribution of individuals in a population (e.g. humans and plants).
• Limiting Factors- things that prevent a population from growing any larger (e.g. available food, shelter, water, etc.).
• Density Independent- effects population size regardless of the population's density (e.g. weather).
• Density Dependent- intensify as the population increases in size (e.g. disease, predation, and competition).
• Exponential Graph- no limiting factor "J Curve"

  
• Logistic Growth- population grows exponentially until a certain point, then levels off. Influenced by limiting factors "S Curve."

  
• Carrying Capacity - the maximum number of individuals of a species that can survive together without resources being depleted (running off).

  
• Random Sampling- used for populations that do not move. An average of the population size is made using a grid and selection of sections at random.
• Mark and Recapture- used for populations that move or are hidden from view. Sample of the populations is captured, marked, returned. Later another portion is captured and the number of marked individuals within the sample is counted.
• R- Strategist- small organisms with short life spams, produce many offspring but do not provide a lot of parental care, population size varies (e.g. spider/spider fly).
• K- Strategist- large organism with long life spams, reproduce only a few times but provide a lot of parental care, population size is stable (e.g. elephants).
• Trophic Levels- the position in a food chain of an organism (troph- = eat)
• 10% Rule- only 10% of the energy is transferred from 1 trophic level to the next.
• Producers (Autotrophs)- organisms that make their own food by photosynthesis (e.g. plants).
• Primary Consumer (1st Order Heterotroph)- consumes primary producers; herbivores (e.g. bunny).
• Secondary Consumer (Second Order Heterotroph)- eats primary consumers; omnivores or carnivores (e.g. fox).