Ecology Scientific study of interactions among organisms and between organisms and their physical environment
Biosphere: All life on earth and parts of earth in which life exists (land, water and atmosphere)
Studying Our Living planet • Science of Ecology • Study of interactions of living things, their surroundings or environments • Ecology and Economics • Humans live in biosphere and depend on ecological processes to provide essentials (water and food) which can be bought and sold. • Levels of Organization • Species to biosphere
Levels of Organization • Species-Similar organisms that can breed and produce fertile offspring • Population- group of individuals that belong to the same species/live in same area • Community-Different populations that live together in defined area. • Ecosystem-organisms, their space and the physical environment
Levels of Organization continued. • Biome-Group of ecosystems that share climates and typical organisms • Biosphere-Entire planet, all organisms, and physical environment
Biotic factors Biological influences of organisms Eg. Other living organisms, food
Abiotic factors Physical components of an ecosystem Eg. Sunlight, humidity, wind or water currents.
Ecological Methods • Observation-where live? How many live here? How animals protect young? • Experiment-used to test hypothesis. How do growing plants react to different variables? • Modeling-make models-global warming happens over time. Use mathematical formulas based on data.
Organisms and Energy Energy needed to grow, reproduce and metabolize Organisms can not create energy, must get it from other sources
Primary Producers • Autotrophs-capture sunlight or chemicals and convert it into forms that living cells can use. • Primary Producers-first producers of energy-rich compounds that are later used by other organisms. • Eg. Plants, Algae and certain bacteria. Auto = self (Greek) Trophe = Food or nourishment (Greek)
Energy from Sun The best-known and most common primary producers harness solar energy through the process of photosynthesis
Life without Lights Biologists have discovered thriving ecosystems around volcanic vents in total darkness on the deep ocean floor.
Life Without Light Deep-sea ecosystems depend on primary producers that harness chemical energy from inorganic molecules such as hydrogen sulfide. The use of chemical energy to produce carbohydrates is called chemosynthesis.
Consumers Organisms that rely on other organisms for energy and nutrients
Organisms that must acquire energy from other organisms by ingesting in some way are known as heterotrophs.Heterotrophs are also called consumers. Heter= other
Types of consumers • Classified by the ways in which they acquire energy and nutrients. • Carnivores kill and eat other animals, and include snakes, dogs, cats, and this giant river otter. • Catching and killing prey can be difficult and requires energy, but meat is rich in nutrients and energy and is easy to digest.
Consumers Types continued. • Scavengers, like a king vulture, are animals that consume the carcasses of other animals that have been killed by predators or have died of other causes.
Consumer Types cont. • Decomposers, such as bacteria and fungi, feed by chemically breaking down organic matter. The decay caused by decomposers is part of the process that produces detritus—small pieces of dead and decaying plant and animal remains.
Consumer Types cont. • Herbivores, such as a military macaw, obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits. Common herbivores include cows, caterpillars, and deer.
Consumer Types cont. • Omnivores are animals whose diets naturally include a variety of different foods that usually include both plants and animals. Humans, bears, and pigs are omnivores.
Consumer Types cont. • Detritivores, like giant earthworms, feed on detritus (debris) particles, often chewing or grinding them into smaller pieces. Detritivores commonly digest decomposers that live on, and in, detritus particles.
Decomposer Organisms that breakdown and absorb nutrients from dead organisms. Fungi, protozoan's, bacteria
Beyond Consumers Categorizing consumers is important, but these simple categories often don’t express the real complexity of nature. For example, herbivores that eat different plant parts often differ greatly in the ways they obtain and digest their food.
Not one size fits all In addition, organisms in nature often do not stay inside the categories we put them in. For example, some carnivores will scavenge if they get the chance. Many aquatic animals eat a mixture of algae, bits of animal carcasses, and detritus particles. It is important to expand upon consumer categories by discussing the way that energy and nutrients move through ecosystems.
Energy Flow in ecosystems How does it flow? Three types of ecological pyramids
Energy Flow One-way stream Primary producers to various consumers
Food Chain Series of steps in which organisms transfer energy by eating and being eaten Feeding relationships
Food Chains • Vary in length • Aquatic food chain primary producers are a mixture of floating algae called phytoplankton
Food Web: network of feeding interactions • Network of food chains • More complex than food chain; still simplified
Vocabulary Convert means “to change from one form to another”. Decomposers convert dead plant matter into a form of debris called detritus that was eaten by detritivores
Decomposers break down dead and decaying matter and release nutrients that can be reused by primary producers w/o decomposers, nutrients would be locked within dead organisms
Food Webs and Disturbances • So complex, often difficult to predict exactly how they will respond to environmental changes. • Oil spill • Decline in number of bacteria and fungi that break down detritus? • How will effect populations of crayfish? • Populations decline? If decline how will that affect their predators feeding behaviors?
Zooplankton Diverse group of small, swimming animals that feed on marine algae
Trophic Levels Steps in food chain or food web (feeding levels) PRIMARY PRODUCERS ALWAYS first tropic level. One organism can be at different trophic levels
Ecological Pyramids: illustrate relative amounts of energy or matter contained with in a trophic level in a given food chain or food web.
Pyramid of Energy • Show relative amount of energy available • No limit to the number of trophic levels or number of organisms • Only small portion of energy goes from one trophic level to the next. ( 1/10 or 10% goes to next level) • Expend energy for life processes (growth, respiration, movement and reproduction) • Released as heat
a.If there are 1000 units of energy available at the producer level of the energy pyramid, approximately how many units of energy are available to third-level consumers? b.What is the original source of energy that flows through the ecosystems? Why must there be a continuous supply of energy into the ecosystem? c.Why are there usually fewer organisms in the top of an energy pyramid?
biomass Amount of living tissue within a given trophic level (measured in grams of organic matter per unit area)
Pyramid of biomass: illustrates the relative amount of living organic matter available at each trophic level in an ecosystem
Pyramids of Numbers: relative number of individual organisms at each trophic level in an ecosystem
Exceptions • Some cases consumers are less massive than the organisms they feed upon. • Sometimes pyramid of numbers may be turned upside down.