Ecology Environmental Interactions What is ecology? • “Eco”= environment, house • “Ology”= study of • Ecology- the scientific study of interactions among organisms and their environment or surroundings • The study of ecology looks primarily at the biosphere, or area where all life exists. • “Bio”= Life • “Sphere”= circle, zone How do we organize and group life? • A species is a group of organisms so similar to one another that they can breed and produce fertile offspring • A species is the most specific grouping of life • Example= grey wolf • All the wolves that live in one area would be called a population, or group of individuals that belong to the same species and live in the same area. • If we wanted to look at all the different populations that live in an area, we would be looking at a community, or the assemblage of different populations that live together in a defined area. Ex. All the animals and plants in a • Keep in mind that a forest community only involves the living, or biotic factors!! Bringing it all together… • The next level of organization is the ecosystem. - In an ecosystem, we study a collection of all the living organisms that live in a particular place Ex. Forests together with their nonliving, or abiotic, environment. The final step… • The final and largest level of organization (excluding the biosphere), is the biome. • Biomes are groups of ecosystems that have the same climate and similar dominant communities… Biomes of the World… • Tropical Rainforest • Tropical Dry Forest • Tropical Savanna • Temperate Grassland • Desert • Temperate woodland and scrublands • Temperate Forest • Northwestern coniferous forest • Boreal Forest (Tiaga) • Tundra • Mountains and Ice Caps • Bodies of Water What makes them unique and different from one another? • Location around the globe • Climate • Dominant plant and animal species Tropical Rainforest – Climate: hot, wet – Soil: thin, poor – biodiversity: high Tropical Dry Forest – Climate: warm, alternating wet and dry – Soil: rich – biodiversity: average Tropical Savanna – Climate: warm, seasonal rainfall – Soil: compact – biodiversity: average Deserts – Climate: variable temps., low rainfall – Soil: rich in minerals, poor in organics – biodiversity: average to low Temperate Grasslands – Climate: warm summers and cold winters, moderate precipitation – Soil: fertile – biodiversity: average Temperate Woodland and shrubland – Climate: warm, dry summers and cold, moist winters – Soil: thin, poor – biodiversity: average Temperate Forest – Climate: warm summers and cold winters, year round precipitation – Soil: fertile – biodiversity: average Northwestern Coniferous Forest – Climate: mild temperatures, abundant precipitation fall, winter, and spring – Soil: rocky, acidic – biodiversity: average Boreal Forest – Climate: mild summers and long, cold winters, moderate precipitation – Soil: acidic, poor – biodiversity: average Tundra – Climate: short, soggy summers and long, dark, cold winters, low precipitation – Soil: poorly developed, permafrost – biodiversity: low And the rest… • Mountains • Ice Caps • Aquatic Biomes – Oceans – Lakes – Rivers – Ponds – Etc. Let’s go to the video… • Biomes Energy Flow Through an Ecosystem Ways of acquiring energy • Autotrophs- can make their own energy by converting the energy of the sun into food. These organisms are also called producers. Acquiring Energy Con’d • Heterotrophs- Organisms that get their energy by consuming other organisms. Also known as consumers. Can an organism be both??? • YES!!! – Venus flytrap – sun dew – Pitcher plant One more way to “power up” • Chemotrophs are able to combine different chemical compound (without light) to make power. This process is called chemosynthesis. How they all interact… • When an organism obtains energy by eating only plants, it is called a herbivore… • If they eat only meat, they are carnivores… • Eating plants and meat make an organism an omnivore… Bottom Feeders… • Detritivores feed on the remains of plants and animals along with other dead material called detritus. • This includes worms, snails, mites, and…. crabs “Stinky dead animals,” brought to you by… • Decomposers- break down organic matter • Examples: bacteria, fungus Putting them all together… • Feeding relationships are shown using two different graphs, food chains and food webs. – Food chains show a series of steps in which organisms transfer energy by eating and being eaten. Webs… • Food webs are a network of complex interactions that show feeding relationships. – Webs are better at showing actual interactions on a large scale The levels of organization • Each step in a food chain is called a trophic level. • They go as follows: Top level carnivores 1st level carnivores herbivores producers Trophic levels Trophic levels con’d • Available energy at each level is shown on an ecological pyramid. • Numbers represent percentage of original sunlight energy still available for use… • Available energy: – Producers= 100% – Herbivores (primary consumers)= 10% – 1st level carnivores (2ndary consumers)= 1% – 2nd level carnivores (tertiary consumers)= .1% Ecological pyramid Community Interactions A few terms… • Biotic factors- biological (living) influences on organisms within an ecosystem • Ex. Trees, birds, people, etc. • Abiotic factors- physical, or nonliving, factors that shape ecosystems • Ex. Rivers, wind, soil, temperature, etc. • Habitat- the area where an organism lives More terms… • Niche- the full range of physical and biological conditions in which an organism lives and the way the organism uses those conditions – Baseball players – Each person on the field has a job and a specific place to do that job, that is their “niche” Resources • Resources are necessities of life and include water, nutrients, light, food and space. – What happens if two organisms both want to use the same resources?? Resources • This idea that no two species can occupy the same niche in the same habitat is called the competitive exclusion principle. • Though no two organisms can occupy the same niche, they do interact in many different ways. Forms of interaction • Predation- one organism captures and feeds on another • Symbiosis- any relationship where two organisms live closely together – Forms of symbiosis: • Mutualism • Commensalism • Parasitism Mutualism (+/+) • This type of symbiosis provides a benefit for both organisms involved – Ex. Bees and flowers, hummingbird and flowers, etc. Commensalism (+/neutral) • This type of symbiosis provides a benefit for one organism involved but doesn’t harm or help the other organism – Ex. Whales and barnacles, orchids and trees, etc. Parasitism (+/-) • This type of symbiosis provides a benefit for one organism involved but harms the other organism – Ex. Dog and flea, people and mosquitoes, etc. Video Time… • symbiosis How do populations grow? • - Populations are constantly changing in number. A few ways this happens are: – Deaths – Births – Immigration – Emigration • All of these factors control the population density, or number of individuals per unit of area… • Immigration (+)- the movement of an individual into an area. Population increases • Emigration (-)- the movement of an individual out of an area. Population decreases • One cannot happen without the other In what ways do populations grow? • If unlimited resources are available, a population will grow at an exponential rate, or without limitation and at a constant rate. – growth starts at a low number but increases quickly • Example: a single bacterium lands on your food, has offspring, who have offspring, who have offspring and so on doubling their numbers every 20 minutes • a few become many... Growth continued • If for some reason resources do become limited, our bacteria would switch to a pattern of logistical growth, or a time where a population’s growth slows or stops after a period of exponential growth. – Could be caused be high death rate, low birth rate, limited resources, etc. Carrying Capacity • All growth is controlled by an imaginary number called the carrying capacity. – Carrying capacity is the maximum population number an area can support long term. Ecological Succession Changes over time… • What is ecological succession? – A series of predictable changes that occurs in a community over time. • As an ecosystem changes, older inhabitants gradually die out and new organisms move in causing further changes to the community Primary Succession • Succession that takes place where no soil previously existed is called primary succession. – Soil is created through the weathering of rock and breakdown of organic material • May happen after a volcano or glacier Primary succession • The 1st species to populate this newly created soil is called a pioneer species. – These species add organic material to the nutrient poor soil as they die. • Ex. Lichen (fungus + algae) Secondary succession • Succession that takes place following a disturbance that destroys a community without destroying the soil is called secondary succession. – What kind of disasters might do this?? • Floods, fires, hurricanes, tornadoes, etc. Nutrient Cycling Nutrients • Nutrients are nature’s building blocks, or all the chemical compounds that an organism needs to sustain life. • Essential nutrients include: – Carbon - Iron – Nitrogen - Zinc – Phosphorus - Potassium – Oxygen - Fluorine – Hydrogen - Calcium – Magnesium - many, many, others!! Limited nutrients • When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, that substance is called the limiting