I. INTRODUCTORY TERMS AND CONCEPTS:
Because this WWW page examines several of Hawaii’s endangered and threatened marine species including the Humpback whale, Hawaiian monk seal, green sea turtle, and dolphins, it seems appropriate to first become familiar with some of the key terms and concepts you will encounter.
Endangered refers to a species whose population is declining drastically, and is in danger of extinction.
Threatened applies to those species whose population levels are declining and that are likely to become endangered in the forseeable future.
A species is a group of living organisms (plants, animals, or microbes) that breed under natural conditions and are reproductively isolated from other populations. If species considered endangered or threatened are not protected they may become extinct. Species become extinct when all individuals of that species die. When this occurs, the species and all the genes of that particular species’ genetic line are lost forever. To prevent extinctions it is important to protect and show respect for the earth’s biodiversity.
Biodiversity refers to the total number of species, genes, and ecosystems found on our planet. It is a representation of the wealth of life on earth, a wealth which has undergone hundreds of millions of years of evolutionary history, and to which many human cultures have become adapted. Biological resources provide mankind with all of its foods, and form the basis of many medicines and industries. The enormous variety of life in the form of genes, species, and habitats has incredible value as it allows humans to successfully meet the demands of the ever-changing environment in which we live.
Scientists estimate the total number of living species to be close to 10 million, yet little more than 10% of these species have been identified. The full potential of our biological wealth therefore remains unknown and untapped. Nonetheless, largely due to human activity, we are currently experiencing the greatest loss of diversity of species, genes and ecosystems since the mass extinctions of prehistoric times, some 65-500 million years ago. Recent estimates indicate that 50,000 species become extinct each year. Many losses occur without man knowing their complete role within the earth’s ecosystem and the impact that their absence will have. Major causes for the increased loss of biodiversity involve trade or consumption of endangered species and loss of habitat and resources through human development.
II. HOW AN ECOSYSTEM WORKS:
An ecosystem refers to all the living organisms and their non-living environment within a given area. Note that this definition includes two components; the living component which consists of the animals, plants and microbes, and the non-living component which refers to the air, water, rocks, soil and weather.
There is no limit to how large or small an ecosystem can be. An ecosystem can be as large as an ocean or as small as a puddle. Very large ecosystems are known as biomes. An important point to recognize about ecosystems is the interaction between a grouping of plants and animals and their non-living environment and how the two strive to achieve a balance.
Ecology relates to the study of ecosystems. Scientists who study the different components of ecosystems and how they are related to one another are called ecologists. Ecologists have determined that the populations of many species if left undisturbed by humans will remain relatively unchanged over time. Why then are so many species becoming extinct? Today, extinction rates are thousands of times greater than the natural rate.
To better understand the reasons for this, it is first important to learn about the different factors affecting the living and non-living components of ecosystems and how they are interelated.
One factor which has a great impact on an ecosystem is the number of living organisms there are in a particular ecosystem. The number of individuals of each species present in the ecosystem is determined by that species’ rate of population growth. There are three factors involved in how the size of a species population changes over time. They are:
-Migration into (immigration) or out of (emigration) the population
A change in the population size of a given species can be determined by subtracting the number of individuals that leave a population (through death or emigration) from the number of individuals that join a population (through birth or immigration).
Change in Population Size = # Individuals that JOIN – # Individuals that LEAVE
(birth + immigrants) – (death + emigrants)
From this we can see the following:
– That a population will remain unchanged if as many individuals leave as join.
– That if more individuals join a population than leave population growth will result.
– That if more individuals leave a population than join a population decline will result.
The rate at which the population of a given species grows or declines is also affected by a number of factors related to the species’ life history strategy . These include:
– The age at which the species is first able to reproduce
– The frequency with which reproduction occurs
– The number of offspring produced per reproductive effort
– The number of years a species is able to reproduce
– The average life expectancy of the species
Another factor which has a great impact on the balance of an ecosystem is the availability of resources. Resources are those things necessary for a species’ survival and successful reproduction. Resources can be of two types: renewable and non-renewable.
Renewable resources are those which are able to be renewed or replaced. These include food (nutrients), water, mates and light.
Non-renewable resources are those which are not able to be replaced. Only a finite amount of these resources exist. Space and territory (habitat) are examples of non-renewable resources.
The number of living organisms an ecosystem is able to support is directly related to the amount of renewable and non-renewable resources present in the ecosystem. Under natural conditions, most populations will stabilize at a level known as the carrying capacity of the ecosystem. The carrying capacity is the maximum number of organisms that an ecosystem can support on a continued basis. In most cases, an ecosystem’s carrying capacity is determined by the availability of resources such as space, nutrients, water and light.
Interactions between species or between members of the same species often determine who will be successful in obtaining resources and who will survive. Such types of interactions include competition and predator-prey relationships. Competition occurs when two individuals (or species) both attempt to utilize a resource (such as food or space) that is limited relative to the demand for it. Predator-prey relationships occur when one organism (the predator) kills and eats another living organism (the prey). In predator-prey relationships, one organism is the resource! Once all members of a prey species are gone the predator will have to look for alternative sources of food for energy.
This brings us to the next factor that affects how an ecosystem functions– this is how energy flows within an ecosystem. Regardless of their size, the energy flow within all ecosystems is pretty much the same. The sun is the ultimate source of energy in most ecosystems and for almost all living things. Energy from the sun flows through ecosystems allowing nutrients to be produced.
Nutrients in turn, cycle and recycle within the ecosystem in the following way: Plants are the primary producers in most ecosystems. They are able to use the light energy from the sun to produce carbohydrates through a process called photosynthesis. In addition to sugar which is a carbohydrate, oxygen is given off as a by-product as shown in the reaction below:
Sun + H2O+ CO2 ———-> C6H12O6 + O2
Organisms that rely on the carbohydrates produced by plants for their means of energy are called consumers. There are usually several levels that energy flows through from producers to consumers. Each level is called a trophic level. As mentioned, all of the organisms (mostly plants and some bacteria) that obtain their energy directly from the sun and use it to produce carbohydrates are called primary producers. Primary producers make up the lowest trophic level. The second level consists of those organisms which feed entirely on plants. These organisms are are known as herbivores or primary consumers. Carnivores are those organisms that feed on herbivores and other animals. They are referred to as secondary consumers and make up the third trophic level. Occasionally some carnivores eat other carnivores. When this happens, they form the fourth trophic level: tertiary consumers. Organisms from each of these four levels feed on one another with each level feeding directly on the level below it, making up a series called a food chain. The length and complexity of food chains vary greatly. In the wild, it is rather rare for one type of organism to feed on only one other kind of organism; usually, each will feed on two or more kinds, and in turn will be fed on by several other kinds of organisms. This type of complex feeding arrangement within an ecosystem is referred to as a food web.
III. HUMAN IMPACT AND RESPONSIBILITY:
Humans are continually having an effect on and being affected by the environment. We are an integral part of nature. The ways which people interact with the environment directly reflect how they understand and care for it. We must all learn the importance of E malama ia Hawai’i: to take care of our island home and the organisms which inhabit it. Hawaii is home to more unique species than any place of similar size on Earth. It also has the distinction of being the place on Earth with the highest concentration of species that are seriously threatened with extinction. For many of Hawaii’s endangered species, loss of habitat through human activity is the primary cause for population decline. Over 50% of Hawaii’s natural communities are considered critically endangered. Although the loss of single species is a serious concern, the loss of entire ecosystems represents a crisis for all of Hawaii’s living organisms, even humans, as we also depend the natural resources they provide. Loss of a single species is only an indicator that something very serious is happening to the environment and to the world. Our day-to-day survival depends on the maintenance of a healthy, natural environment. We must learn to better balance our needs with those of nature in order to care for Hawaii’s future.
What is man without the beasts?
If all the beasts were gone, man would die from loneliness of spirit.
For whatever happens to the beasts, soon happens to man.
All things are connected.
Chief Seattle, 1854
It is important of course to care for all of the Earth, but taking care of Hawai’i is a good way to begin. You can think of the Earth as an island, just like Hawai’i. Just as there is only one Hawaii, there is only one Earth. Just as Hawaii floats in the middle of the Pacific Ocean, the Earth floats in space; and, just as Hawaii has only so much space and so many resources that must be shared with all creatures, large and small, so does the Earth. Once our territory and resources are used or damaged, they are difficult, if not impossible to replace. Many of our actions have consequences that affect the environment today and will continue to do so for a great many years. It is important for us to incorporate responsibility for the environment into our daily lives, not only for our future, but for the future of those to come. This is what stewardship is all about.
IV. HAWAIIAN PERSPECTIVES ON THE OCEAN
Ancient Hawaiians recognized the importance of stewardship, but perceived it as more of a “kinship”. They believed that humans are related, or are “kin”, to the oceans and all of their living components. They believed that man’s relation to the oceans deserves the same kind of protection and respect that relationships among humans require. Hawaiians saw the ocean as more than an “environment” or “resource”. They felt the ocean was a living being- a home to other living beings and to living gods- something that should be shared, not controlled. The traditional Hawaiian perspective on the oceans and relationship to them is perhaps best illustrated through the Kumulipo, or Hawaiian chant of creation.
The Kumulipo not only follows the evolutionary progression of living creatures from the oceans to the land, but also illustrates how the oceans are an integral part of air, land, weather, and of plants and animals found everywhere. In addition, the Kumulipo reminds us that the oceans are a source for many things beyond those of economic or transportation value. The Kumulipo describes how the oceans are also a source of health, providing a variety of medicines for physical and emotional well being, as well as serving as a source for cleansing, healing and nourishing the spirit, and for learning the ways of nature.
The full chant is over 2,000 lines, and too long to be included here in its entirety. To get a better sense of what the Kumulipo is all about, portions of it (in both Hawaiian and English,) along with a more detailed summary have been provided as part of the supplementary materials that accompany this curriculum. The entire chant is found in Kumulipo, Hawaiian Hymn of Creation by Rubellite Kawena Johnson.
SUGGESTED RESOURCES FOR TEACHERS
– Have students name species which they think are endangered or threatened and discuss the reasons why they think the species are or could be endangered. Pictures could be drawn of different species or they could be cut out of magazines and made into a collage.
– Have students describe an ecosystem of their choice. In their description they should identify as many living and non-living components as possible. They should also be able to describe the flow of energy within the ecosystem.
– As a class, make a list of everything the students had to eat for lunch. Beside each food item note if the item is a producer or a consumer, and what trophic level it most likely belongs to.
– Describe or draw a graph illustrating what is likely to happen to a population that far exceeds the carrying capacity of its ecosystem.
– As a group, discuss whether you consider wildlife to be a renewable or a non-renewable resource? Explain your answer(s).
– List some human activities that have expanded the earth’s carrying capacity for people. List some human activities that have reduced the earth’s carrying capacity for other species. List some things that can be done to try and protect different endangered species.
– Describe or draw a diagram illustrating how energy flows within a particular ecosystem. Don’t forget to include man’s position(s) in the energy flow if applicable.
– As a group, discuss students answers to the following question: If you had the authority and the financial assets to take any means necessary to protect and preserve the world’s biodiversity, but could only take one what means would you take and why?
– Select an endangered species that you care about. Write a poem or draw a picture illustrating why this species is important to you.
– As a class, write letters to your state and national representatives, encouraging them to take action on a conservation issue you feel strongly about. In your letters let them know how you feel and what action you would like them to take and why.
– Organize and carry out a class beach-pick up. Have students note the amount of different types of trash they collect. Discuss how each type of trash can be harmful to the environment (i.e., biodegradable, non-biodegradable, plastics, toxins, etc.) and what happens to trash once it is thrown “away”. (Where is “away” anyway?)
– Engage class in a discussion regarding things that can be done to help protect Hawaii’s marine environment, and the global marine environment for that matter. Your discussion should touch on aspects of public education, creating laws and policies, and economic considerations.