Fundamentals of Ecology Chapter 2 Fundamentals of Ecology

Unit Objectives Define ecology Define ecology Differentiate between biotic and abiotic Differentiate between habitat and niche Define homeostasis List and define the physical factors influencing the aquatic environment List the factors that influence the distribution of species

Unit Objectives Understand the flow of energy in marine systems Understand the flow of energy in marine systems Differentiate between a food chain and a food web

A. Study of Ecology 1. Environment 1. Environment a. biotic factors b. abiotic factors 2. Habitat: where an organisms lives

Study of Ecology 3. Niche: an organism’s “role” in the environment 3. Niche: an organism’s “role” in the environment environmental factors biological factors the organism’s behavior

Environmental Factors Affect Organism Distribution Maintaining homeostasis homeostasis and the distribution of marine organisms optimal range zones of intolerance

Environmental Factors Affect Organism Distribution Physical environment sunlight photosynthesis vision desiccation temperature ectotherms endotherms

Environmental Factors Affect Organism Distribution salinity solutes osmosis solutes in the body fluids of organisms regulation of solutes in body fluids

Environmental Factors Affect Organism Distribution pressure 760 mm Hg (14.7 psi) or 1 atmosphere at sea level increases 1 atmosphere for every 10 meters below sea level Ex: Every 33 ft pressure increases another 14.7psi 60 miles of air creates pressure that is equivalent to 33ft. of seawater

Environmental Factors Affect Organism Distribution metabolic requirements nutrients and limiting nutrients oxygen as a requirement for metabolism anaerobic and aerobic organisms eutrophication and algal bloom metabolic wastes carbon dioxide is a common byproduct of metabolism

Environmental Factors Affect Organism Distribution Biological environment competition may be interspecific or intraspecific may result in competitive exclusion resource partitioning allows organisms to share a resource predator-prey relationships balance of abundance of prey vs. predators keystone predators boom-or-bust cycles result from imbalances

Environmental Factors Affect Organism Distribution: symbiosis: living together mutualism – both organisms benefit from the relationship parasitism – the parasite lives off the host; the parasite benefits while the host is harmed commensalism – one organism benefits, whereas the other is nether harmed nor benefited

Populations and Communities Population – a group of the same species that occupies a specified area Community – composed of populations of different species that occupy one habitat at the same time

Populations and Communities Population growth there are many ways in which a population can increase in size e.g., recruitment exponential growth logistic growth carrying capacity

Populations and Communities Distribution of marine communities pelagic division neritic zone and oceanic zone plankton and nekton benthic division shelf zone, bathyal zone, abyssal zone, and hadal zone epifauna and infauna photic zone, disphotic zone, and aphotic zone

Ecosystems: Basic Units of the Biosphere Examples of ecosystems estuaries salt marshes mangrove swamps rocky shores sandy beaches kelp forests coral reefs open ocean

Ecosystems: Basic Units of the Biosphere Energy flow through ecosystems Producers photosynthetic producers chemosynthetic producers

Ecosystems: Basic Units of the Biosphere Measuring primary productivity rate at which energy-rich food molecules are being produced from inorganic matter light-dark-bottle method measuring carbon in organic products of photosynthesis

Ecosystems: Basic Units of the Biosphere Consumers first-order consumers second- and third-order consumers detrivores decomposers Food chains and food webs Other energy pathways dissolved organic matter (DOM) detritus

Ecosystems: Basic Units of the Biosphere Trophic levels number is limited because only a fraction of the energy at one level passes to the next level ecological efficiency 10% rule trophic pyramids as energy passed on decreases, so does the number of organisms that can be supported

Biogeochemical Cycles Hydrologic cycle water is lost through evaporation returned through precipitation and runoff

Biogeochemical Cycles Carbon cycle carbon released from organisms through respiration and decomposition recycled by photosynthetic producers carbon is used in shells, corals and skeletons as part of calcium carbonate

Biogeochemical Cycles Nitrogen cycle producers use nitrogen to synthesize proteins (amino acids) bacteria recycle nitrogen from wastes and decomposing, dead organisms fixation of atmospheric nitrogen by microorganisms