Introduction To Ecology Ch. 50

Introduction To Ecology  Ecology – the scientific study of the interactions between organisms and their environments  Ecology determines both the distribution and abundance of organisms  Distribution and abundance depends on abiotic (non-living factors such as temperature, light, water, nutrients, pH, etc.) and biotic (living factors such as all the living organisms) components of the environment

Levels of Ecological Study 1. Organismal Ecology – morphological, physiological, and behavioral way in which individual organisms meet the challenges posed by their abiotic and biotic environments

Levels of Ecological Study A population is a group of individuals of the same species living in a particular geographic area  Population Ecology – factors that affect how many individuals of a particular species live in an area

Levels of Ecological Study A community consists of all the organisms of all the species that inhabit a particular area; it is an assemblage of populations of many different species 3. Community Ecology – the whole array of interacting species in a community (includes predation, competition, and disease)

Levels of Ecological Study An ecosystem consists of all the abiotic factors in addition to the entire community of a species that exist in a certain area; may consist of many different communities 4. Ecosystem Ecology – the emphasis in on the energy flow and the cycling of chemicals among the various biotic and abiotic components

Levels of Ecological Study  The Biosphere is the global ecosystem, the layer of Earth inhabited by life; the sum of all the plant’s ecosystems

Factors Affecting Distribution  Biogeography – the study of the past and present distribution of individual species  In studying the dispersal of organisms, ecologists work through a series of logical steps to determine what limits geographical distributions

Factors Affecting Distribution  Of course, we do not want to purposely introduce organisms to areas where they do not already exist  Examples – African Honeybee (purposely) and Zebra Mussel (accidentally)  Tens Rule – one out of ten introduced species becomes established, and one out of ten established species become common enough to become pests.

Factors Affecting Distribution  Behavior and habitat selection Habitat selection by ovipositing insects, which often choose only certain host plants, may limit their distribution Habitat selection by ovipositing insects, which often choose only certain host plants, may limit their distribution  Biotic Factors The inability to survive and reproduce may be due to predation, disease, or competition The inability to survive and reproduce may be due to predation, disease, or competition  Abiotic Factors Temperature, water, sunlight, wind, and rocks and soil Temperature, water, sunlight, wind, and rocks and soil

Factors Affecting Distribution  Temperature and moisture are the major climatic factors determining distribution  Climate is the prevailing weather conditions of a locality and are influenced by temperature, water, light, and wind  Biomes are major types of ecosystems found in broad geographic regions

Solar Radiation and Latitude

What Causes Seasons?

Lake Stratification and Seasonal Turnover

Aquatic Biomes  Freshwater biomes – less than 1% salt concentration  Marine biomes – average of 3% salt concentration  Oceans influence global rainfall, climate, and wind patterns  Marine algae and photosynthetic bacteria produce a large portion of the world’s oxygen and consume enormous amounts of carbon dioxide

Aquatic Biomes

Freshwater Biomes

An Oligotrophic Lake A Eutrophic Lake A River

Freshwater Biomes  Wetlands – areas covered with water and supporting hydrophytes (water plants); range from marshes to swamps to bogs These richly diverse biomes are important to flood control and water quality These richly diverse biomes are important to flood control and water quality

Freshwater Biomes  Estuaries – where a freshwater river or stream meets the ocean; often bordered by wetlands called mudflats and saltmarshes Serve as feeding and breeding areas for marine invertebrates, fish, and waterfowl Serve as feeding and breeding areas for marine invertebrates, fish, and waterfowl

Marine Biomes

 Intertidal zones – the daily cycle of tides exposes the shoreline to variations in water, nutrients, and temperature, and to the mechanical force of wave action Rocky intertidal zones have organisms adapted to firmly attach to the hard substrate Rocky intertidal zones have organisms adapted to firmly attach to the hard substrate Sand or mudflat intertidal zones are home to burrowing worms, clams, and crustaceans Sand or mudflat intertidal zones are home to burrowing worms, clams, and crustaceans

Marine Biomes  Coral reefs – found in tropical waters in the nertic zone; are highly diverse and productive biomes  Coral reefs are easily damaged by pollution, development, native and introduced predators, and high water temperatures

Marine Biomes  Benthos – nutrients reach the benthic zone as detritus falling from the waters above. Nertic benthic communities receive sunlight and are very diverse and productive Nertic benthic communities receive sunlight and are very diverse and productive Various invertebrates and fishes that are adapted to cold, dark, and high water pressure inhabit the abyssal zone Various invertebrates and fishes that are adapted to cold, dark, and high water pressure inhabit the abyssal zone Chemoautotrophic prokaryotes are adapted to the hot, low-oxygen environment surrounding deep-sea hydrothermal vents Chemoautotrophic prokaryotes are adapted to the hot, low-oxygen environment surrounding deep-sea hydrothermal vents

Terrestrial Biomes

 The geographic distribution of the world’s major terrestrial biomes is related to abiotic factors – in particular, the prevailing climate  Biomes are usually named for their predominant vegetation and major climatic features  Each bio also has characteristics microorganisms, fungi, and animals

Tropical Forests  Occur within 23° latitude of the equator  Variation in rainfall result in tropical dry forests, tropical deciduous forests, and tropical rain forests, where rainfall is abundant

Savanna  Tropical and subtropical grassland with scattered trees and rainy and dry seasons  Fires and large grazing mammals restrict vegetation to grasses and small broad-leaved plants

Deserts  Characterized by low and unpredictable precipitation  May be hot or cold depending on location  Desert animals have physiological and behavioral adaptations to dry conditions  Plants may use CAM photosynthesis and have water storage adaptations and protective spines and poisons

Chaparral  Common along coastlines in midlatitudes that have mild, rainy winters and hot, dry summers  The dominant vegetation – dense, spiny evergreen shrubs – is maintained by and adapted to periodic fires

Temperate Grasslands  Maintained by fire, seasonal drought, and grazing by large mammals  Soils are deep and rich in nutrients

Temperate Deciduous Forests  Characterized by broad-leaved deciduous trees  Grow in midlatitude regions that have adequate moisture to support the growth of large trees  Trees drop their leaves before winter

Coniferous Forest (Taiga)  A large biome found in northern latitudes  Characterized by harsh winters with heavy snowfall  Coniferous trees grow in dense, uniform stands  Coastal temperate rain forests area also coniferous forests

Tundra  The northernmost limit of plant growth  Characterized by dwarfed or mat-like vegetation  The alpine tundra, found at all latitudes on high mountains above the tree line, has similar flora and fauna  The artic tundra has a shallow root layer due to permafrost, permanently frozen soil