2 Ch. 2 Ecological Principles

2.1  What is biodiversity?

What is biodiversity?  As the word implies, it is all the different forms of life.  This includes all species, as well as the genetic variability within species.  It also includes higher levels of biological organization:  Ecosystems, communities, and all of the species interactions that are included within these systems.  Human diversity is included in this definition of biodiversity; different races, ethnicities and cultures.

Scientists have organized biodiversity in several ways.  One of these is called the hierarchical organization of life.  A hierarchy is a system where items are put into levels based on perceived importance, status or size.  In biology, the hierarchy is more or less by size, from small and simple to large and complex, as follows (underlined terms are the most important for this book):

• Atoms: Subtatomic particles organized into the smallest particle of a chemical element
• Molecules: Two or more atoms bonded together (ex: water H20, carbon dioxide CO2). Within every species, genes are contained in specialized molecules called DNA (DeoxyriboNucleic Acid).  DNA contains our genetic material, coded in a sequence of simple structures called nucleic acids.
• Organelles: Specialized structures made of molecules (ex: mitochondria, nucleus).
• Cells: Cell organelles bound by a cell membrane, forming the smallest structural unit of living matter capable of functioning independently
• Tissues: Groups of similar cells working together
• Organs: Groups of tissues which perform specific functions for an individual organism (ex: skin, muscles, liver, heart, blood, nervous system)
• Individual organism: A living being capable of using energy, containing at least one cell
• Population: A group of individuals, regularly interbreeding and sharing a large amount of genetic similarity
• Species: A species is a group of several populations; individuals within these populations are capable of interbreeding and producing fertile offspring.
• Community: A group of species living in the same area, relating to each other through species interactions
• Ecosystem: All of the natural communities in a certain area, and the physical environment (all interacting living and non-living parts) (Ex: lake, grassland, coral reef)
• Biosphere: All of the ecosystems on earth are connected into one living, interconnected system

Scientists also organize diversity based on similarities or differences in characteristics.  This is the taxonomic organization of life.  They are as follows:

Domain🡪Kingdom 🡪 Phylum 🡪 Class 🡪 Order 🡪 Family 🡪 Genus 🡪 Species

It is easy to remember this sequence with the mnemonic device:

Did King Philip Come Over For Good Spaghetti?

1. Domain Archea: Single-celled organisms without a nucleus; live in harsh environments; cell membrane, metabolism and genetic material are all different from the Bacteria
2. Domain Bacteria: Single-celled organisms without a nucleus; live in many different environments
3. Domain Eukarya (also called Eukaryotes): All have cells with a nucleus. Divided into 4 Kingdoms:

• 1) Protist Kingdom: Single-celled organisms, such as amoeba, paramecium, diatoms, and some multi-cellular organisms such as algae, seaweeds (250,000 known species)
• 2) Fungi Kingdom: Single-celled organisms such as yeasts, and multi-celled organisms including fungus, molds and mushrooms. All of them are heterotrophic (=get their food from other organisms).
• 3) Plant Kingdom: Mostly multi-cellular organisms, mostly autotrophic (=create their own food, through photosynthesis): Major groups: Mosses, ferns, conifers, flowering plants
• 4) Animal Kingdom: Multi-cellular organisms, heterotrophic. Often divided into Invertebrates (animals without a backbone) and Vertebrates (animals with a backbone). Divided into Phyla as follows:
  1. Porifera: Sponges
  2. Cnidaria: Jellyfish, corals
  3. Platyhelminthes: Flatworms
  4. Nematoda: Roundworms
  5. Annelida: Earthworms
  6. Mollusca: Clams, shellfish, octopus, squid
  7. Arthropoda: Shrimp, insects
  8. Echinodermata: Starfish, sea urchins
  9. Phylum Chordata: Animals with a backbone.  Subdivided into the following classes:

1. 1. • Class: Fish: Sharks, salmon, trout,
      • Class: Amphibians: Salamanders, frogs
      • Class: Reptiles: Snakes, iguanas, turtles
      • Class: Birds: Ducks, songbirds, hawks, herons, shorebirds
      • Class: Mammals: Primates (humans, apes, monkeys, chimps), cetaceans (whales, dolphins); carnivores (dogs, cats)

There are thought to be roughly 30 million different species of organisms on earth; only 1.8 million of those have been named and described.  About 1.3 million of the named are animals, and roughly 290,000 are plants.  Most of the unnamed species are thought to be plants and microscopic species, such as bacteria and algae.

The species is arguably one of the most important units of organization.  NOTE: The word species is the same whether singular or plural, so specie is NOT a real word.  Species are known by their common name, as well as their Latin name; the Latin name is the genus, with the genus being capitalized, followed by the species, and the word is italicized or underlined.  Example: Domestic cat (house cat): Felis domesticus, wolf is Canis lupus.  Sometimes, there is enough information about the species to determine that there are several distinct races or subpopulations.  Thus, Canis lupus is divided into Canis lupus familiaris (domestic dog), and 32 other subspecies, for example the dingo Canis lupus dingo.  All of these are genetically similar enough to be the same species, which means that they could mate and produce fertile offspring.

Activity:  Divide your class into five groups, one for each continent (except Antarctica and Australia). Find out the scientific name, common name, size and geographic distribution for any species in the cat genus (Felis).  Post this information, with a photo, onto the class padlet for this assignment. 

2.2  What is Sustainability?

The field of environmental science arose in response to rising awareness of the impacts of humans on the natural world.  As far back as the —th century, people in Europe and other increasingly populated areas realized that too much hunting, or too much tree-cutting, could have devastating effects on all life forms.  When white settlers, accustomed to the major areas of deforestation and reduced animal populations of Europe, first came to North America, they were amazed at the seemingly endless forest, fields, streams and coastlines, and all the abundance of creatures they offered.  Within a few hundred years, however, many of the populations of fish, deer, buffalo and top predators were decimated, prairies and forests were converted to farms, rivers were dammed and polluted, and wetlands were drained and filled.  This habitat destruction was accelerated by the invention of the steam engine, and the use of fossil fuels to power the industrial era.  Starting after WWII, modern chemistry invented new pesticides, fertilizers and industrial plastics and other chemicals, which created both important new products to facilitate a growing human population, as well as life-altering pollutants.

The goal of the field of environmental science is to understand the human-nature relationship and to solve the problems created by the imbalances in that relationship.  Ultimately, we seek  to create a sustainable society.   Defining a sustainable society is almost as difficult as achieving one, however.  The first major attempt at a definition came in 1986, from an international commission chaired by Gro Brundtland, Prime minister of Norway.  The Brundtland report defined sustainable development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

However, other scholars criticized this definition for its lack of specificity.  Development is not clearly defined, nor is the future generations clear: future generations of all life forms, or just humans?   Three dimensions of sustainability were identified: Social, economic and environmental.  The social dimension ensures that there is justice and equity for all classes, races, genders and identities of humans, both in the outcome, and in the process of decision-making.  The economic dimension is really a component of the social, but it emphasizes that all groups share equally in in the financial costs or benefits, in terms of jobs, income, etc.    The environmental dimension must include all species, and must ensure that we can living with the resources that earth has to offer, without depleting them:  this is called living within ecosystem limits.

Further discussion and research focused on four essential qualities that must be embedded in any definition of sustainability.

1. Improvement in quality of life for ALL species
2. Some sense that this improvement will be maintained into the future
3. Fairness in the process: Were all affected groups included in the decision-making process, and were all affected groups and species considered?
4. Limits of supporting ecosystems are not exceeded.   As you can imagine, it is not easy to determine whether a given situation is sustainable or not, because it is difficult to get all the information required to assess the components included above.

Unfortunately, we don’t always know what the limits of an ecosystem might be, and it is not constant – it changes all the time with changing climate, human impacts and other variables.   In determining if an activity is environmentally sustainable, a full life cycle analysis must be conducted.  This means that the environmental impacts of every step of the activity has to be considered: from raw materials, to production, to use and finally to disposal.   This has led to the introduction of the following definition of a sustainable society, which will be used in this book:

A sustainable society is one that ensures a better quality of life for all species, now and into the future, in a just and equitable manner, whilst living within the limits of supporting ecosystems.  

Every chapter in this book contains a story of a sustainable solution to an environmental problem described in the chapter.  As you read each sustainability story, you need to decide if it addresses all of the major components of sustainability in the definition.  The concept of equity  and justice, among different kinds of people, different generations (present and future), and among different species, is clearly represented in this definition.    Look for:

2.3  Values of biodiversity

As we seek to create a sustainable society, one of the most important concepts to understand is the importance of all forms of biodiversity.  You have already learned that biodiversity includes many levels of organization: genes, individuals, populations, species, communities, ecosystems, and species interactions.  Biodiversity has value, meaning its importance, on many levels.   These values can be classified into 4 different categories.

1. Intrinsic value. Intrinsic means innate or fundamental; intrinsic value refers to the fundamental importance of a species or ecosystem, just because it exists. We can think of intrinsic value as the importance of the species or ecosystem to itself. Whether it does anything good or bad for another being, that species has intrinsic value.  This is more of a philosophical construct than a scientific one.

2. Ecological value: Ecology is the study of the relationship between living creatures. Ecological value is the importance of the gene, species, ecosystem etc. to other species.  A species may be an important food item, it may create structure for other species to hide in, or an ecosystem may provide nutrients or habitat for species, or provide water or nutrients for an adjacent ecosystem.  Some examples of species with particularly high ecological value include:

• Foundational species: A foundational species is one that creates the basis for the ecosystem in which it lives.  An example of this would be the corals in a coral reef; corals are actually groups of tiny animals that create hard structures, that other species then live in and on.  Another example would be the grasses in a prairie or the trees in a forest.  The grasses provide all of the food that supports the food chain in the prairie.  The trees provide food as well as structure.
• Keystone species: A keystone species is one that alters the ecosystem in some way that allows many other species to survive.  An example is the beaver.  Beavers build dams, which convert streams into ponds and wetlands, creating more habitat for fish, amphibians, insects and many other species.  Apex predators are another example of a keystone species.  An apex predator is a top predator whose hunting activities keep the herbivore population under control.  An example is the wolf.  When there are no wolves in an area, the elk or moose or other herbivore populations eat all the young trees and shrubs.  When the wolves come back, they reduce the herbivore population so that the plants can grow back, and other species that need those trees and shrubs can thrive.  Keystone species which create major physical changes in the environment, such as beavers, are also called ecosystem engineers.

3. Economic value: Biodiversity has economic value if it makes money or saves money for humans. Trees in a forest can be bought and sold.  This is an example of direct economic value, when the item can be actually harvested and sold.  Indirect economic value is present when the species or ecosystem saves money for humans by providing ecosystem services or other benefits.  Ecosystem services are benefits provided to humans by natural ecosystems for free.  A forest holds the soil in place, preventing erosion which can damage water supplies, and forests also provide oxygen and purify the air.  If the forest were gone, erosion would occur, and people who have to pay to fix the damage.  Also, once the forest is gone, the air would not be as clean, and people would either suffer from poor health, and have to pay for health care, or they would have to pay for a system to clean the air, which the forest did for free!

4. Aesthetic value: Aesthetics refers to visual or other sensory qualities (hearing, smelling, etc.). A species or ecosystem has aesthetic value if humans enjoy looking at it, hearing it, smelling it, etc.,   Most humans value the ocean or any clean body of water for its aesthetic values.  Similarly, even though most of us will never see a wild snow leopard or a giant anaconda snake, we enjoy watching videos of them because they are “cool” or fun to watch, which is an example of aesthetic value.  Although aesthetic  value can exist even when it is free, it often creates indirect economic value, because a house with a view of the ocean is worth more money, and people make a lot of money selling photos and videos of interesting species or ecosystems!

Activity:  Identify all of the values of (a) a sandy beach, where people can sunbathe, swim, fish, collect shells, seabirds nest and find food, and the dunes provide protection from wind and waves for the houses built behind them; (b) a black bear, which is an omnivore that eats ants, berries, fish, birds’ eggs, grass; (c) a freshwater marsh, where fish and frogs lay their eggs, ducks and geese create nests, and pollution is filtered out; (d) a gene in a bacteria which scientists can use to help treat a disease in humans.