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 nutrient. – Three of the most common limiting nutrients are: • Nitrogen • Potassium • Phoshporus – How do farmers deal with this problem?? Productivity

• Limiting nutrients along with overall nutrient availability affect an ecosystem’s primary productivity. – This is the rate at which producers in the ecosystem make organic matter Cycling nutrients

• Matter is recycled between and within ecosystems. What kinds of matter? – Water – Carbon – Nitrogen – phosphorus

• Biogeochemical cycles are the pathways that elements, compounds, and other forms of matter are passed from one organism to another or from one area to another. The Water Cycle

Moving H2O • - Water is carried from the clouds to ground through precipitation. • - As it moves across the ground, some is taken back to a gaseous form through evaporation. • - Plants lose small amounts of water through transpiration. • - As water accumulates, it forms back into liquid water by the process of condensation.

The Carbon Cycle

• A large percentage of carbon is found in the

atmosphere as CO2

• CO2 is collected by plants and turned into organic tissue during the process of photosynthesis. • This organic matter is eaten, broken down, and

given off as waste CO2 and returned to the atmosphere

– It can also be burnt, which also gives off CO2 • When organisms die, the carbon stored in their

bodies returns to the atmosphere as CO2 as they decay and returned to the soil as they decompose.