Ecology

What is Ecology? Ecology is the study of the interactions among organisms and the interactions between organisms and their environment. It breaks down our environment into individual components and analyzes what effect these components have on the larger system.

Levels of Ecological Organization Six levels Individual Population Community Ecosystem Biome Biosphere

Individual One organism Example: 1 elk or 1 apple tree

Population A group of the same species living in a given area at the same time Example: 300 Elk in the Upper Dolores River Valley

Community Groups of different populations living in the same area at the same time Example: All of the plants and animals in the Upper Dolores River Valley

Ecosystem A collection of all the organisms in a given area AND the nonliving material in an environment. Example: All of the living organisms (communities) and nonliving material in the Upper Dolores River Valley

Biome A particular physical environment that contains a characteristic collection of plants and animals. Examples: Desert, Tundra, Tropical Rain Forest

Biosphere All the living organisms and non living material on planet Earth.

How do we experiment on an ecological scale? 1) Observing 2) Experimenting 3) Modeling

Observing Studying ecology depends on making observations of organisms in the habitat they live because this cannot be recreated in a laboratory. Observations involve being methodical and consistent.

Experimenting With so many variables involved with ecology, it is important that experiments are well thought out. Ecologists can set up artificial environments in a lab to conduct experiments, and many can be done in the natural environment.

Modeling Many ecological interactions occur over a long period of time (even hundreds of years) or involve a large area (hundreds of square miles). This makes these interactions difficult to study. Scientists have to model these interactions to gain an understanding.

Where does energy come from? Sunlight is the major source for life on Earth. Without sunlight, almost all life on Earth would not exist.

Producers Producers, or Autotrophs, produce their own energy from either the sun or nonliving material in the environment. There are 2 processes which producers can make energy: Photosynthesis Chemosynthesis

Producers Photosynthesis is where an organism uses sunlight to combine Carbon Dioxide + Water which creates Sugar (energy) + Oxygen. creates the oxygen we breathe. The green color in plants is chlorophyll.

Producers Chemosynthesis is where an organism takes non-living material and carbon dioxide and transform it into sugars. This is very rare. Only happens in unique environments like hydrothermal vents on the ocean floor and hot springs

Bacteria in Yellowstone Hot Springs

Tube Worms on Hydrothermal Vents

Consumers Consumers, or Heterotrophs, are organisms that rely on other organisms for energy. Consumers are subdivided into: Herbivores Carnivores Omnivores Detritivores

Consumers Herbivores Herbivores are organisms that eat only plants to survive. Examples: cows, caterpillars, deer

Consumers Carnivores Carnivores eat other animals to survive. Examples: snakes, dogs, owls

Consumers Omnivores Organisms that eat both plants and meats. Examples: chickens, humans, bears

Consumers Detritivores Eats dead organisms to survive. Examples: earthworms, snails, crabs

Decomposers Decomposers consume dead material to survive, include bacteria and fungi.

Ecosystems Aspects of Ecosystems: Habitat – the area where an organism lives ♦ the organisms address Niche – the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions ♦ the organisms occupation ♦ what it does

Feeding Relationships in Ecosystems Energy flows through an ecosystem in one direction: sun (or inorganic compounds) to autotrophs (producers) to heterotrophs (consumers)

Different classifications of feeding relationships include: Food Chains Food Webs Trophic Levels

Feeding Relationships in Ecosystems Food Chain A series of steps where energy is transferred by eating and being eaten. One specific path of energy.

Example of a Food Chain

Feeding Relationships in Ecosystems Food Web The complex interactions of energy transfer of various organisms. All the food chains of an area combined into the “big picture”

Example of a Food Web

Feeding Relationships in Ecosystems Trophic Levels Different levels of a food web/chain Roman Numerals indicate the different trophic levels within a food web/chain

Example of Trophic Levels

Ecological Pyramids An Ecological Pyramid is a diagram that shows the relative amount of energy, matter, or numbers within each trophic level. Three ecological pyramids are: Energy Pyramid Biomass Pyramid Pyramid of Numbers

Energy Pyramid Diagram that displays how much energy is transferred to/from each trophic level Only about 10% of energy from each trophic level is transferred to organisms in the next trophic level

Energy Pyramid

Ecological Pyramids Energy Pyramid

Ecological Pyramids Biomass Pyramid Diagram displaying how much biomass there is at each trophic level

Biomass Pyramid

Ecological Pyramids Pyramid of Numbers Diagram showing the number of organisms at each trophic level

Pyramid of Numbers

Ecosystems Ecosystems are influenced by: Biotic Factors Abiotic Factors

Ecosystems Biotic Factors – biological influences on organisms within an ecosystem - all organisms: plants, animals, bacteria,... - affected by how many organisms are present

Ecosystems Abiotic Factors – physical, or non-living, factors that shape an ecosystem - climate (temperature, precipitation) - wind - soil type - sunlight

Ecosystems Climate vs. Weather WWeather – day-to-day conditions of Earth’s atmosphere at a particular time and place ♦ changes all the time CClimate – the average, year-to-year conditions of temperature and precipitation ♦ what you would expect on average

Ecosystems Biotic and Abiotic factors determine: * the survival and growth of an organism * the productivity of the ecosystem in which the organism lives

Ecosystems Community Interactions: Competition Predation Symbiosis

Ecosystems Community Interactions: Competition – when organisms attempt to use the same ecological resource in the same place at the same time ♦ food, water, light, space

Ecosystems Community Interactions: Predation – when one organism feeds on another organism ♦ predators vs. prey

Ecosystems Community Interactions: Symbiosis – when two species live closely together ♦ Mutualism – both species benefit ♦ Commensalism – one organism benefits while the other organism is neither helped or harmed ♦ Parasitism – one lives in or on another organism and harms it

Ecosystems Aspects of Ecosystems: Habitat – the area where an organism lives ♦ the organisms address Niche – the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions ♦ the organisms occupation ♦ what it does

Populations Three important characteristics that affect populations: Geographic Distribution Density (Population Density) Growth Rate

Populations Three important characteristics that affect populations: Geographic Distribution – the area inhabited by a population ♦ the range of the population

Populations Three important characteristics that affect populations: Density (Population Density) – number of individuals per unit area

Populations Three important characteristics that affect populations: Growth Rate – how the numbers within a population change ♦ number of births ♦ number of deaths ♦ number of individuals that enter or leave the population

Populations Three important characteristics that affect populations: Growth Rate Types of Growth ♦ Exponential Growth – will happen under ideal conditions

Populations Three important characteristics that affect populations: Growth Rate Types of Growth ♦ Logistic Growth – population’s growth slows or stops after exponential growth ■ known as S-curve

Populations Three important characteristics that affect populations: Growth Rate Types of Growth ♦ Logistic Growth ■ Carrying Capacity – largest number of individuals that a given environment can support

Populations Three important characteristics that affect populations: Growth Rate Limiting Factor – something that causes populations growth to decrease ● competition ● weather ● predation ● national disasters ● parasitism ● disease ● seasonal cycles ● human activities