Chapter 5Environmental Science

• Energy for Life

• Photosynthesis / Respiration

• Trophic Levels

• Cycles

• Succession

Energy Types and Qualities

• Energy is define as the the ability to do work and can take many forms(light, heat, electricity etc.), and is measured in calories, BTU, or joules

• The energy found in a moving object is called Kinetic energy(KE=1/2mv2). Heat measures the total kinetic energy in a a substance. Temperature is a measure of the speed of motion of atoms or molecules in a substance. Heat and temperature are not the same.

• Potential energy is the stored energy that is latent but available for use (PE=mgh)

Energy

• Food, gasoline are examples of chemical energy.

• Power is defined as the rate of doing work

• Energy can be either low or high quality.

Thermodynamic and Energy Transfer

• The study of thermodynamics deals with how energy is transferred in natural systems– The first law of thermodynamics states that energy is

conserved: that it is neither created or destroyed. It may change forms but the total amount of energy does not increase or decrease

– The second law of thermodynamics states that, with each energy transfer or transformation in a system, less energy is available to do work.

• Natural systems tend to move towards a higher state of entropy or disorder and lowest energy

Cells Fundamental Units of Life

• All living things are composed of cells

• Organisms may be composed of many cells (multicellular)or single cells(monocelluar or unicellular)

• Cells are composed of a membrane and organelles

• Metabolism, all the reactions carried out by a cell.

Energy for Life

• Most organism depend either directly or indirectly on the sun for the energy needed to create structures and carry out life processes

Energy Quiz

• 1.Define Energy• 2.What are the 2 types of Energy?• 3.What is the Earth’s source of Energy?• 4.What happens to the total energy at

each stage in an energy transfer 1,2,3,4,5?

• 5.As a bowling ball is approaching the pins it is transferring Potential Energy, into ____ Energy.

Energy Quiz

• 1.Define Energy. Ability to do work• 2.What are the 2 types of Energy?

Potential/Kinetic• 3.What is the Earth’s source of Energy? Sun• 4.What happens to the total energy at each

stage in an energy transfer 1,2,3,4,5? Decreases Energy available

• 5.As a bowling ball is approaching the pins it is transferring Potential Energy, into ____ Energy. Kinetic then reverses

Solar Energy: Warmth and Light

• Solar Energy is essential for life• Most organisms survive within a narrow

temperature range. The necessary heat is provided by the sun.

• Organisms depend on solar radiation for life sustaining energy. Which is captured by green plants, alga and some bacteria in a process called photosynthesis. Only about 1-2 % of the total solar radiation hitting the earth is utilized by plants.

Photosynthesis and Energy

• Chlorophyll, a green molecule found in chloroplasts within plant cells, absorbs light energy and uses it to create high-energy chemical bonds in substances that serve as the fuel for all subsequent cellular metabolism.

• Chlorophyll is assisted in this process by a large group of sugar, lipids proteins and nucleotide molecules.

• The light reaction is photosynthesis occur only while the chloroplast is receiving light energy. They result in the splitting of a water molecule to form molecular O2 and small high energy molecules that serve as fuel for the dark reaction of photosynthesis.

• The dark reactions of photosynthesis can occur after light is no longer being received. They result in the addition of a carbon atom to a small sugar molecule.

Photosynthesis Respiration

• Photosynthesis can be summed as 12H2O + 6CO2 + Solar E. (Chlorophyll)-> C6H12O6 + 6O2 + 6H2O

• Cellular respiration is the process in which glucose (the sugar) is split apart and its energy is released for use by cellular metabolism. Mitochondria

• Animals do not have chlorophyll and gain their energy by eating other plant or animals breaking down their organic molecules for energy

• C6H12O6 + O2 Mitochondria-> CO2 + H2O

6CO2+12H2OC6H12O6 + 6O2 + 12H2OEnzymes, Sunlight and Chloroplast(chlorophyll)

Photosynthesis/Respiration

• Quiz– 1.What two compounds

come together in the first stage of photosynthesis?

– 2.What are the products of photosynthesis?

– 3.What part of the plant cell is responsible for making this reaction go?

– 4.Are Carbon atoms created or destroyed during photosynthesis?

– 5.Where does cellular respiration take place?

Photosynthesis / Respiration

• Quiz– 1.What two compounds

come together in the first stage of photosynthesis?

– 2.What are the products of photosynthesis?

– 3.What part of the plant cell is responsible for making this reaction go?

– 4.Are Carbon atoms created or destroyed during photosynthesis?

– 5.Where does cellular respiration take place?

• Answers– 1.CO2,H2O– 2.Glucose,C6H12O6– 3.Chloroplasts with

Chlorophyll– 4.neither– 5.Mitochondria

Food Chain, Food Web and Trophic Levels

• Photosynthesis is the base of the energy economy of most ecosystems.

• Chemosynthesis is used in some ecosystems. Chemosynthesis is when small organisms break down compounds for energy.

• Productivity is the amount of biomass produced in a given area during a given time period.– Photosynthesis is described as primary productivity because it is the

basis for almost all other growth in an ecosystem.– Manufacture of biomass by organisms that eat plants is termed

secondary productivity.

• A food chain is a linked feeding series of organisms.• Individual food chains may inter connect to form a food

web.

Producers and Consumers

• Producers (autotrophs) are organisms that transform solar energy into chemical energy

• Consumers (heterotrophs) are organisms that consume the chemical energy harnessed by producers – Organisms that can be identified by there trophic level

at which they feed and by what kinds of foods they eat (herbivores, carnivores, omnivores)

– Scavengers, detritivores and decomposers also occupy important places in the trophic levels

Autotrophs-Makes their own organic matter from inorganic

nutrients and environmental Energy sources

Hetertrophs-Must feed on organic matter for energy

Producers

PhotosyntheticPlants

Photosynthetic Bacteria

ChemosyntheticBacteria

Consumers

Primary ConsumersHerbivores

Omnivores

Secondary ConsumersCarnivores

Parasites

DecomposersDetritus Feeders

Decomposers

Detritus Feeders

Terms• Carnivores- • Herbivores- • Omnivores-• Scavengers-• Detritivores- • Decomposers- • Saprophytes-• Consumers-Heterotroph• Producers-Autotroph

Terms

• Carnivores-organisms that eat only meat• Herbivores-organisms that eat only herbs, vegetarian • Omnivores-organism that can eat anything• Scavengers-organism that eats things that die or are

killed by something else. Road kill, Buzzards, crows, coyotes, hyenas.

• Detritivores-organisms that live off of dead organic material.

• Decomposers-organisms that break down dead organisms or organic matter. Bacteria or Mushroom.

• Saprophytes-a plant type that breaks down dead material, usually a mushroom.

Energy

Consumed

Not Consumed

Digested

Undigested Wastes

Growth, Repair

Energy for Metabolism

Heat

Wastes

Ecological Pyramids

• By arranging organisms in a food web by trophic level, an ecological pyramid is formed with producers on at the wide base and fewer and fewer individuals in the higher levels. This follows the second law of thermodynamics that less and less energy is available in each succeeding trophic level

• The Pyramids may be of three types, Biomass, Numbers, Energy

• The total number of organisms and total biomass in each successive trophic level in an ecosystem may also form pyramids

This an Owl Pellet, note the amount of fur, and tissue. How many rodents do you think the owl needs to survive one night?

This is close-up of the bones found in the owl pellet.

Materials Cycles and Life Processes

• Maintenance of conditions suitable for life on earth require constant cycling and recycling of essential nutrients and substances.

• You should become familiar with the cycles for carbon, nitrogen, phosphorus and sulfur. Each cycle is under the direction of natural and human –influenced factors

The Carbon Cycle• Carbon serves two purposes for organisms: Structural

component of organic molecules, energy holding bond represents energy “storage”

• The C cycle begins with the the intake of CO2 by photosynthetic organisms. C and O are important in the constructing the sugar molecule. The molecule is taken up by other organisms and CO2 is released by respiration.

• Not all C is cycled, coal, oil, limestone may sequester the molecule for millions of years.

• Tying up C in the bodies and byproducts of organisms it helps balance CO2 generation and utilization and regulates the greenhouse effect.

• Oceans and heavily vegetated areas are important carbon sinks

Carbon Cycle

CO2 in Air Plants

Animals

CO2 in WaterCaCO3Shells Limestone

Fossil Fuels

Diffusion

Diffusion

Burning

Sedimentation

Decay, Incomplete Decay

DigestionRespiration

Photosynthesis

Respiration and decay

Absorbed

The Nitrogen Cycle• Nitrogen is the major limiting factor in terrestrial plants.• Organisms cannot exist without amino acids, peptides and

proteins which are all molecules containing N. Making N the major limiting factor in terrestrial ecosystems.

• Although the most abundant gas in our atmosphere, plants cannot use N2 gas.

• Nitrogen fixing bacteria convert N2 to NO2 and another group converts that to NO3 which can be utilized by plants. Plants convert the NO3 to ammonia(NH4) which is used to build amino acids

• Some plants (legumes) have N fixing bacteria living in their roots, and are very important to agriculture.

• Nitrogen reenters the environment in several ways; death, animal excrement. Denitrifying bacteria break down into N2

Nitrogen Cycle

PlantProtein

Animal Protein

NitratesNO3

Nitrogen

(N2)

Urea,AmmoniaUric Acid

NitritesNO2

Excretion and decay

Death and decay

Eaten and Assimilated

Absorbed

Denitrifying Bacteria

LighteningLegumes

Nitrifying bacteria

Nitrosofying bacteria

Fertilizers

• Synthetic fertilizers may cause an excess of nitrogen in the environment, leading to the acidification of lakes and rivers, blooms of toxic algae, loss of soil nutrients and rising atmospheric concentrations of the greenhouse gas nitrous oxide

• NPK, nitrogen, phosphorus and potassium

The Phosphorus Cycle• Minerals are available to organisms after they have been

released form rocks. Both P and S are examples• Phosphorous is important because it is an essential

component of many high energy compounds such as ATP• The phosphorous cycle begins when P compounds are

leached from rocks and minerals (P cycle has no gas stage)• Inorganic P is taken in by producer organisms, incorporated

into organic molecules and passed on to consumer organisms

• High concentrations of P in aquatic ecosystems may lead to algae blooms suffocating other life in lakes and streams. P is the major limiting factor for aquatic vegetation.

The Sulfur Cycle

• S compounds are a minor essential portion of protein molecules

• Inorganic S stored in rocks is released into the air and water by weathering, volcanic eruptions, and sea floor vent emissions

• The cycle is complicated by the many oxidation states of S. Which state you find it in depends on the O concentration, pH and light levels

• Human activities result in the release of large quantities of S contributes to acid rain, greenhouse effect and human health problems

• Release of Dimethylsulfide (DMS) by oceanic phytoplankton could be a feedback mechanism that keeps temperatures within a suitable range for life.

Symbiosis• Symbiosis is the intimate living together of members of two

or more species.– In contrast to predation and competition, symbiotic

relationships can be non antagonistic• Commensalism is the type of symbiosis in which one

member clearly benefits and the other is neither benefited or harmed.(cattle and egrets, mosses, bromeliads and other plants growing on trees)

• Mutualism is an association in which both of the partners benefit. lichens, algae and fungi)

• Parasitism is the relationship in which one member benefits and the other is harmed

• Symbiotic relationships often have some degree of coadaptation or coevolution of their partners, shaping, or at least in part structural or behavioral characteristics (mutualistic coadaptation)

Energy Transfer Quiz

• Carnivores- • Herbivores- • Omnivores-• Scavengers-• Detritivores- • Decomposers- • Saprophytes-• Consumers-Heterotroph• Producers-Autotroph

• Symbiosis• Commensalism• Mutualism• Parasite / host• Predator prey

Defensive Mechanisms• Many plants and animals have toxic chemicals, body armor and

other adaptations to protect themselves(animals produce noxious fluids or poisons;plants produce oils, resins, sharp bristles)

• Batesian mimicry-harmless species will evolve colors, patterns, body shapes that mimic species that are unpalatable or poisonous

• Muellerian mimicry-two species both of which are unpalatable or dangerous have evolved to look alike so that when predators learn to avoid both species.

• Species also evolve amazing abilities to avoid being discovered. (walking stick)

• Predators use camouflage to hide as they lay in wait for their prey. (Polar bears, scorpion fish)

Community Properties

• Showing how fundamental properties of communities and ecosystems are affected by factors such as tolerance limits, species interaction, resource partitioning, evolution and adaptation.

Productivity• Primary productivity rate of biomass production is an indication of the

rate of solar energy conversion to chemical energy.• The energy left after respiration is the net primary production.• Photosynthesis rate are regulated by many factors;light, moisture,

temperature, nutrient availability• Tropical forests, coral reefs, and estuaries have high levels of

productivity due to abundance of resources.• Other systems do not have sufficient levels of the resources. Deserts

lack water, Tundra lack suitable temperatures, Open ocean lacks nutrients

• Even in the most active ecosystem, only a small % of the available sunlight is converted.– Leaf surfaces reflect light– Most sunlight that is absorbed is converted to heat is either radiated

away or dissipated by evaporation and water.

Abundance and Diversity• Abundance is the expression of the total number of

organisms in a biological community• Diversity is the measure of the different species, ecological

niches or genetic variation present.• Abundance of a particular species is often inversely related to

total diversity of the community.• Communities with a large number of species often have only

a few members • Climate and history are important factors that dictate the

abundance and diversity in a biological community• Productivity is related to abundance and diversity, both of

which are dependant on:total resource availability, reliability of resources, adaptations of the member species. Interactions between species.

Complexity and Connectedness

• Complexity number of species at each trophic level and the number trophic levels in a community.– Diverse communitity may not be very complex

if all species are clustered in only a few trophic levels.

– Diverse community may be complex if it has many interconnected trophic levels that can be compartmentalized into subdivisions

Resilience and Stability• Three types of stability or resiliency in ecosystems.

– Constancy-lack of fluctuation in composition or functions– Inertia-resistance to perturbations.– Renewal-ability to repair damage after disturbance

• 1955 Robert McArthur proposed that the more complex and interconnected a community is, the more stable and resilient it will be in the face of disturbance.

• David Tilman found that plots of native prairie and recovering farm fields with high diversity were better able to withstand and recover from drought those with only a few species.

• In highly specialized ecosystems, removal of a few keystone species can eliminate many other associated species

a.Random

b.Orderly

c.Clustered

Community Structure

• Structure patterns of spatial distribution of individuals and population within the community and the relation of a particular community to its surroundings.

• Individuals within a population can be distributed randomly, in regular patterns, or clumped together.

• Larger communities often contain a mosaic of smaller units or subsets of the whole assemblage.

• Subunits develop because each species has a preference for specific, localized conditions.

• Patchiness patterns of smaller units or subsets of the whole assemblage

• Distribution in a community can be vertical as well as horizontal.

Edges and Boundaries• Edge effects relationship of the boundary between one

habitat and its neighbors.• Edge of a patch of habitat can relatively sharp and distinct

(woodland patch into grassland)• Some organisms prefer this type of habitat(turkey)• Ecotone-the overlapping area between two ecosystems,

with organisms common to both present• Closed community-community that is sharply divided from

its neighbors.• Open community-community with gradual or indistinct

boundaries over which many species cross.• Game management tries to create as much edge to

promote larger game populations. But realize edge creates habitat fragmentation that is detrimental to biodiversity.

Communities in Transition

• Ecological succession is the process by which organisms occupy a site and gradually change the environmental conditions by creating soil, shelter and increasing humidity

• Primary succession;community begins to develop on a site previously unoccupied by living organisms. Once primary succession occurs in an area it is not repeated unless some type of disaster occurs.

• Secondary succession;existing community is disrupted and a new one develops “old field succession”

Stages of Succession• Both types of succession usually follow an orderly sequence of stages.

– Initial colonization(pioneer, lichen)– Replacement by other species (seral communities)(competition,

natural selection, habitat change)– Development of a “stable” species distribution and habitat

• Communities of organisms often become more diverse and increasingly competitive as development continues.

• Climax community;either a primary or secondary community that seemingly resists further change.

• Equilibrium communities;landscapes that never reach a stable climax because they are characterized by and adapted to periodic disruption, fire climax community-communities that are shaped and maintained by periodic fires

Lichen

• Primary Succession• Secondary

Succession• Seral• Climax Community• Pioneers• Ecotone• Edge Effect• Succession

Succession

Lichens

Moss

Fir, Spruce

Juniper

Dandelion, Clovers

Alfalfa

Lambsquarter

Introduced Species and Community Change

• Succession requires the continual introduction of new community members and the disappearance of existing species

• Human introduction of Eurasian plants and animals to non-Eurasian communities often have been disastrous to native species

• Introducing new species in an attempt to solve problems created by previous introductions often make situations worse.

• Zebra mussel, Water hyacinth, walking catfish, English sparrow, rock dove

Chapter 5 Review