OptionEcology and Conservation: G1 Community Ecology

Outline the factors that affect the distribution of plant species including temperature, water, light, soil pH, salinity, and mineral nutrients *High temperature denatures enzymes and retards growth of plants; the rate of transpiration (loss of :water) is also increased. *Low temperatures decrease enzyme activity and freezing temperatures inactivate enzymes Water is needed for enzyme activity, transport, photosynthesis, support, and many other things. Light is important for photosynthesis and flowering Soil pH is important for absorption of nutrients. Salinity has an affect on the absorption through osmosis. High salinity causes plants to lose water through osmosis. Mineral nutrients are needed for many vital functions. Nitrogen is needed to manufacture proteins, enzymes, nucleotides, vitamins, and other compounds. Phosphorous is used in the formation of phospholipid and DNA.

Explain the factors that affect the distribution of animal species including temperature, water, breeding sites, food supply and territory Temperatures affect the concentration of animals. Cold-hot tolerances. Water is needed for vital functions, so only animals that can conserve water are found in deserts. Breeding sites are needed for growth and protection of young. Some need specific areas to breed. Food supply is important for survival since animals are heterotrophs. Some animals are territorial and need large areas for feeding, mating, and protecting their young

Describe one method of random sampling, based on quadrat methods, that is used to compare the population size of two plants or two animal species A sample = part of a population/area In a random sample every individual has an equal chance of being selected Quadrats = sub-sample sizes, within your sample area

Quadrats, Points and Line (Transect Sampling) Pop size estimate = mean # of org/quadrat (x) the total # quadrats in sample area

Niche Concepts Niche Concept – the mode of existence of a species in an ecosystem Habitat – where species live in an ecosystem Nutrition – how food is obtained Interactions/relationships – predator-prey, competition, symbiosis Competitive exclusion principle Realized niche - actual Fundamental niche - potential

Outline the use of a transect to correlate the distribution of plant or animal species with an abiotic variable

Explain what is meant by the niche concept, including an organism’s spatial habitat, its feeding activities and its interactions with other species + distinguish between fundamental and realized niches

Outline the following interactions between species, giving two examples of each: competition, herbivory, predation, parasitism and mutualism

Competition – two individuals (intra) or two species (inter) using the same resources (food, habitat, mates) Terrestrial ex.Aquatic ex.

Species Interactions – Herbivory: a primary consumer feeding on a plant or other producer. Terrestrial ex. Aquatic ex.

Predation – consumers feeding on consumers Terrestrial ex.Aquatic ex.

Parasitism – when an organism feeds on a host without killing it. Terrestrial ex.Aquatic ex.

Mutualism: +,+ relationship between members of two different species Terrestrial ex.Aquatic ex.

Explain the principle of competitive exclusion First proposed by Lokta and Volterra, competitive exclusion takes place when two species need the same resources, and will therefore compete until one species is removed.

Define biomass & describe one method for the measurement of biomass of different trophic levels in an ecosystem Biomass is the dry weight of organic matter in organisms of an ecosystem. Measuring biomass is a destructive sampling technique, so the samples used are as small as possible. Representative samples of all living organisms in the ecosystem are collected, for example from randomly positioned quadrats. The organisms are dried, by being placed in an oven at 60-80°C. The mass of organisms in each trophic level is measured using an electronic balance.