The Biosphere/ Ecology Notes

What is Ecology?

• Scientific study of interactions among organisms and between organisms and their environment

Biosphere

–Combined portions of the planet in which all of life exists, including land, water and air or atmosphere• Extends from 8 kilometers above Earth’s

surface to 11 kilometers below the surface of the ocean

Interactions and Interdependence

• Interactions within the biosphere produce a web of interdependence between organisms and the environment in which they live

Levels of Organization

– Individual: interactions between an organism and its surroundings• cottontail rabbit

– Population: groups of individuals that belong to the same species and live in the same area• group of cottontail rabbits

Levels of Organization

–Communities: different populations that live together in a defined area• rabbits, coyotes, ravens, lizard

– Ecosystem: collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment• rabbits, coyotes, ravens, lizard, rocks, dirt,

climate, water

Levels of Organization

–Biome: group of ecosystems that have the same climate and dominant communities• desert, tundra, tropical rain forest

– Biosphere: planet Earth

Ecological Methods

– Three approaches to ecological research:• Observing: Use of 5 senses to ask

ecological questions• Experimenting: Used to test hypotheses– artificial environment in a lab– within natural ecosystems

Ecological Methods

–Modeling: Used to gain insight into complex phenomena such as the effects of global warming

– may include mathematical formulas based on data collected through observation and experimentation– predictions tested by further observations

and experiments

Biotic and Abiotic Factors• Click on link to see video clip

Biotic Factors

• ‘Bio’- Means ‘life’• Definition - organisms that make up the living

portion of an ecosystem• Also considered the ORGANIC component of

the ecosystem• Ex. Trees, shrubs, insects, animals, algae,

fungi, etc

Abiotic Factors

• ‘Abio’ – Means ‘not life’• Definition – the nonliving features of an

environment• Considered the INORGANIC component of

the ecosystem• Ex. Air, temperature, moisture, light, rocks,

and soil

Energy Flow

• Energy flows from the sun or inorganic compounds to producers.

• Consumers eat producers to get energy.• The primary source of energy on Earth is the

sun!!

Every Organism Has a Home Address

Habitat

• Definition – physical location in which an organism lives

• In other words the home address of a species• Ex. Fern habitat – moist, shady forest floor.

Habitat

• Many animals can share a habitat• A single tree maybe the habitat for several species of birds,

squirrels, etc.• However, each species uses the habitat in a different way.• They all find their niche

• Coral reef biodiversity.

Niche

• Definition – the way a species uses the resources of its habitat and what it does in the community

• Includes: food, living space, methods of obtaining food, etc.

• NO TWO SPECIES CAN OCCUPY THE SAME NICHE

Producers

• Autotrophs – “self feed”• Use sunlight to create carbohydrates via

photosynthesis• Ex – Plants, algae and some bacteria• Some bacteria create organic compounds from

inorganic chemicals – Chemosynthesis– Live in remote places.

PRODUCERS

• Producers make their own food!• They are also called autotrophs• Level 1 on the Trophic Level• Plants and bacteria make up this

group.• They make their food from the sun

called photosynthesis

Producers

CONSUMERS• Consumers are living things that cannot make

food for themselves. (Also called heterotrophs)

• They survive by taking in food that has been made by other living things.

• A food chain contains several kinds of consumers.

• Heterotroph – “Different food”• Must eat to obtain energy.• Ex – animals, fungi, some protists

• YOUR MOM’S A HETEROTROPH!!!

Types of Heterotrophs

• Herbivore – eats plants• Carnivore – eats animals• Omnivore – eats plants and animals• Detritivore – eats detritus (plant and animal

remains)– Ex- snails, crabs, earthworms

• Decomposer – breaks down organic matter– Ex – bacteria and fungi

Carnivore

OmnivoreDetritivore

Decomposers

Feeding Relationships

Energy flows through an ecosystem in one direction, from the sun or inorganic compounds

autotrophs (producers) various heterotrophs (consumers).

• Flows in one direction• Will never return to the same

form in the ecosystem• Conservation of Energy:– Energy changes form– But is never lost

Energy flows…

What happens to all the energy?

• When an organism eats another organism, energy is either:– stored in the tissues of the organism doing the

eating,– used by the organism, or– released as heat.

Food Chain

–A series of steps in which organisms transfer energy by eating and being eaten.• i.e. Wheat mouse snake hawk

Food Web

• Network of complex interactions formed by the feeding relationship among the various organisms in an ecosystem.

Ecological Pyramid

• A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.

• Energy, biomass, and population numbers can all be represented by a pyramid.

Ecological Pyramid

Only about 10% of the energy from one trophic level is stored in the next.

Matter is recycled in ecosystems.

• Matter can be recycled• Matter can be reformed• The basic building

blocks are reused• Conservation of Matter • The Law of Conservation of

Matter states that matter cannot be created or destroyed only transformed from one form to another.

Matter cycles…

The four most abundant elements in living things are…

HHydrogen

OOxygen N

Nitrogen

CCarbon

Cycles of Matter

• Recycling in the Biosphere–Matter is recycled within and between

ecosystems.–Matter moves through an ecosystem in

biogeochemical cycles.

Water Cycle

Carbon Cycle

How carbon is cycled through organisms…

•  

                                                                                                                                                     

                                                                                                                                                                                                                                                                                                                         

Photosynthesis vs. Respiration

• Photosynthesis is the process by which producers convert radiant energy from the sun into chemical energy in the form of glucose (food).

• Cellular respiration is done by both producers and consumers. It uses oxygen to break down glucose into carbon dioxide and water, releasing energy in the process.

Nitrogen Cycle

N2 in Atmosphere

NH3

NO3-

and NO2-

Nitrogen Cycle

– 78% of Earth’s atmosphere is Nitrogen gas = N2

• Nitrogen containing products:

–Ammonia (NH3)

–Nitrate ions (NO3-)

–Nitrite ions (NO2-)

• Nitrogen is needed for protein and nucleic acid synthesis

Nitrogen Cycle

–Converting nitrogen gas into ammonia is called nitrogen fixation.• Only certain types of bacteria can do this.

• Plants use the converted products (NH3, NO3- ,& NO2-) to make plant proteins.

– Some bacteria convert nitrates into nitrogen gas (denitrification).

Phosphorus Cycle

Phosphorus Cycle

–Phosphorus is important for the formation of DNA and RNA molecules.–Phosphorus is not very common and does not

enter the atmosphere, instead it is found mostly on land in rock and soil.

Primary Productivity

• The rate at which producers create organic matter.

• Determines the size of the community.• Limited by availability of nutrients.– Land – phosphorus (P), nitrogen (N), potassium

(K)–Marine – nitrogen– Fresh water - phosphorus

Algal Bloom

Algal Bloom Details

• An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells. Although there is no officially recognized threshold level, algae can be considered to be blooming at concentrations of hundreds to thousands of cells per milliliter, depending on the severity.

• A harmful algal bloom (HAB) is an algal bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms, or by other means. HABs are often associated with large-scale marine mortality events and have been associated with various types of shellfish poisonings.

HAB Dangers

• the production of neurotoxins which cause mass mortalities in fish, seabirds, sea turtles, and marine mammals

• human illness or death via consumption of seafood contaminated by toxic algae

• mechanical damage to other organisms, such as disruption of epithelial gill tissues in fish, resulting in asphyxiation

• oxygen depletion of the water column (hypoxia or anoxia) from cellular respiration and bacterial degradation

HAB commonly referred to Red Tide

HAB effects