Diversity Within Ecosystems
Student Background Information
The following concepts will be discussed in the Diversity Within Ecosystems field trip. Please ensure that your students have an understanding of the following terms and how they all fit together before we head out. Some terms may be new, though some will be review if the students have been on the Habitats and Communities field trip in previous years.
Vocabulary
Habitat: an animal’s home which provides for its requirements to drink water, eat food, shelter themselves from the elements and predators, and allow space to move freely.
Ecosystem: an ecosystem is the combination of living (biotic) and non-living (abiotic) components which create suitable habitats to support life. There is a vast diversity of ecosystems on planet earth ranging from tropical rainforest, to desert, to aquatic, to grassland, to woodland ecosystems, each having their own specialized combination of biotic and abiotic components.
Biotic Component: the living parts of our world, anything from micro-organisms to human beings. Birds, fish, mammals, and arthropods are all living components, as are all vegetation from the smallest dot of lichen to the largest redwood tree.
Abiotic Component: the non-living parts of our world such as sunlight, water, air, rocks, and minerals. These components form large processes of erosion and deposition which are the starting points for soils to form which may support biotic lifeforms. The weather within certain climates will help dictate the plant and animal communities for that area.
Producer: a living (biotic) component which is able to create the nutrients within itself with access to sunlight, water, and minerals. Plants are producers. Through photosynthesis they produce starches, sugars, and proteins by using the sun’s energy to convert carbon dioxide absorbed through the air or the water. The waste product of this conversion is the oxygen which we breathe.
Consumer: a living component which eats (consumes) producers, like grasshoppers, mice, and worms. There is more than one type of consumer, classified depending on that which the consumer feeds. The examples listed above would be considered primary consumers, being that they are at the bottom of the food chain. A secondary consumer is something that feeds on a primary consumer. For example, a snake will eat the mouse. A tertiary consumer is something that will eat both primary and secondary consumers. For example, an owl will eat grasshoppers, mice, and snakes. They are higher on the food chain.
Herbivore: an animal which requires a diet of vegetation for survival. Herbivores eat plant material. For example: deer species, they eat mainly buds off of trees and the seeds and stalks of grasses.
Carnivore: an animal which requires a diet of meat for survival. Carnivores eat other animals. For example: a wolf, they eat mainly large herbivores such as moose and caribou.
Omnivore: an animal which can eat both vegetation and meat to provide for itself. For example: a black bear will eat berries, insects, deer, and dandelions, to name a few.
Scavengers: an animal which relies on eating the remains of dead and decaying materials. For example: a vulture will feed on any leftover pieces of a moose after a wolf pack has fed.
Decomposers:these are organisms which break down organic material and in turn help transfer nutrients back into the soil. For example: fungi will get nutrients from organic material like a fallen tree and break the fibers apart to allow them to crumble back into the soil.
Niche: an animal’s specific adaptation to fit within a habitat; their techniques used to select and acquire food, water, and shelter. For example: owls have adapted to hunt nocturnally, while hawks hunt diurnally, though they hunt similar prey for food.
Bio-Indicators: a biotic component which is typically less tolerant of pollution which therefor may be observed to notice any negative changes in an ecosystem. Birds, amphibians and aquatic invertebrates make good bio-indicators due to their low tolerance to air and water pollution and susceptibility to negative responses to changes in their habitats.
Connections
The abiotic components of our world such as sunlight, air, water, rocks, and minerals create processes of erosion and deposition which begin the cycles that support biotic communities. Wind, water, and varying temperatures will erode and break down rocks and minerals and transport the sediments to new parts of the world. Within these sediments producers may begin to take root. When plant communities establish, consumers will come to feed upon the nutrients that the producers create. When primary consumers like insects and small mammals and birds are populating an area, it creates food opportunities for secondary consumers like snakes, weasels, and medium sized mammals. Secondary consumers will attract tertiary consumers like birds of prey, and large canine and feline species. Left-overs from the feeding done by higher level consumers are eaten by scavengers. As the soil supports plants that are eaten by animals that are eaten by larger animals, the remains are left for decomposers which will break down the organic material of animals and vegetation. The nutrients that the decomposers release back into the soil will help the next generation of plants to grow stronger, which will help the animals feeding on them to grow stronger as well. Thus illustrates a circle of biotic life which is intertwined with the diverse and complex food webs which are the product of the diverse and complex ecosystems which make up the earth.
All over the planet these processes are taking place, all with unique plants and animals due to the specific combinations of biotic and abiotic components available in the region. A vast diversity of ecosystems thus makes up earth, each ecosystem providing unique habitats for the biotic life within to find their own niches to survive with the amount of sunlight, water, and air available.
Humans play a large role in altering the variables which create and maintain healthy ecosystems when we eliminate ecosystems or change them to fit our needs, so it is our job to seek ways to support ourselves while doing as little damage as possible to natural ecosystems and to try to fix any past damage that our ancestors have done. We are biotic components which nourish ourselves off of the resources from the earth; we are not separate from the wild flora and fauna which make it up.
Bio-indicators can be used to monitor the changes we make. Note “The Canary in the Mineshaft” analogy* and its relevance to ecosystem science. Many bird species are intolerant to changes in habitat and ecosystem health and therefore make good bio-indicators. Birds also make good bio-indicators due to the sheer diversity of avian species and their wide variety of niches in ecosystems and food selection. A lot is known about typical bird behavior and therefore it is easy for us to note when typical bird behavior has changed. Amphibians and aquatic invertebrates make good bio-indicators due to the fact that they are immersed within ecosystems which can be easily impacted by changes in chemistry. Amphibians and many arthropods absorb oxygen through their skin and exoskeletons, therefore toxins in the air and water can quickly enter their bodies through this absorption. While some arthropods are intolerant of pollution and very reliant on optimal water quality, like those belonging to the orders classifying dragonflies, mayflies, and caddisflies, others are more tolerant and require less healthy water, like those belonging to the order containing things like blackflies. If we notice a change in population from dragonflies, mayflies, and caddisflies towards one consisting mainly of blackflies, we can recognize the fact that a negative change has occurred within the water.
*Canary in the Mineshaft: back before technological advances brought us sensors and gauges for monitoring the presence of toxins, miners would carry a canary in a cage into the mineshaft to work as an indicator of change in the air quality. As they were mining, often gasses trapped in the layers of rock would escape and could be deadly after prolonged exposure. Since birds are more sensitive to pollution than humans, the miners could notice changes to the canary’s behavior quickly – if it became sluggish or excited, or if it flat out died, they had the opportunity to retreat before too much harm was done to themselves; that is if they were conscious enough of their indicator to notice before it was too late.