READ: Relationships Among Living Things
| Site: | Mountain Heights Academy OER |
| Course: | Integrated Science 8 Q3 |
| Book: | READ: Relationships Among Living Things |
| Printed by: | Guest user |
| Date: | Friday, 4 April 2025, 12:00 PM |
1. Roles in an Ecosystem
Roles in An Ecosystem
What roles do coral reef organisms have?
Corals are not rocks or plants, but little animals that live in a carbonate shell they create. They have a symbiotic relationship with zooxanthellae, tiny photosynthesizing organisms. The zooxanthellae provide food for the coral and the coral provides a safe home for the zooxanthellae. Together they form the base of a complex ecosystem.
Roles in Ecosystems
There are many different types of ecosystems. Climate conditions determine which ecosystems are found in a particular location. A biome encompasses all of the ecosystems that have similar climate and organisms.
Different organisms live in different types of ecosystems because they are adapted to different conditions. Lizards thrive in deserts, but no reptiles are found in any polar ecosystems. Amphibians can't live too far from the water. Large animals generally do better in cold climates than in hot climates.
Despite this, every ecosystem has the same general roles that living creatures fill. It’s just the organisms that fill those niches that are different. For example, every ecosystem must have some organisms that produce food in the form of chemical energy. These organisms are primarily algae in the oceans, plants on land, and bacteria at hydrothermal vents.
2. Producers and Consumers
Producers and Consumers
The organisms that produce food are extremely important in every ecosystem. Organisms that produce their own food are called producers. There are two ways of producing food energy:
- Photosynthesis: plants on land, phytoplankton in the surface ocean, and some other organisms.
- Chemosynthesis: bacteria at hydrothermal vents.
Organisms that use the food energy that was created by producers are named consumers. There are many types of consumers:
- Herbivores eat producers directly. These animals break down the plant structures to get the materials and energy they need.
- Carnivores eat animals; they can eat herbivores or other carnivores.
- Omnivores eat plants and animals as well as fungi, bacteria, and organisms from the other kingdoms.
A llama grazes on a terrace near Machu Picchu, Peru.
3. Review Games
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4. Relationships Between Species
Feeding Relationships
There are many types of feeding relationships between organisms. A predator is an animal that kills and eats another animal, known as its prey. Scavengers are animals, such as vultures and hyenas, that eat organisms that are already dead. Decomposers break apart dead organisms or the waste material of living organisms, returning the nutrients to the ecosystem.
(a) Predator and prey; (b) Scavengers; (c) Bacteria and fungi, acting as decomposers.
Relationships Between Species
Species have different types of relationships with each other. Competition occurs between species that try to use the same resources. When there is too much competition, one species may move or adapt so that it uses slightly different resources. It may live at the tops of trees and eat leaves that are somewhat higher on bushes, for example. If the competition does not end, one species will die out. Each niche can only be inhabited by one species.
Some relationships between species are beneficial to at least one of the two interacting species. These relationships are known as symbiosis and there are three types:
- In mutualism, the relationship benefits both species. Most plant-pollinator relationships are mutually beneficial. What does each get from the relationship?
- In commensalism, one organism benefits and the other is not harmed.
- In parasitism, the parasite species benefits and the host is harmed. Parasites do not usually kill their hosts because a dead host is no longer useful to the parasite. Humans host parasites, such as the flatworms that cause schistosomiasis.
Choose which type of relationship is described by each of the images and captions below:
(a) The pollinator gets food; the plant’s pollen gets caught in the bird’s feathers so it is spread to far away flowers. (b) The barnacles receive protection and get to move to new locations; the whale is not harmed. (c) These tiny mites are parasitic and consume the insect called a harvestman.
5. Summary and Vocabulary
Summary
- Herbivores eat plants, carnivores eat meat, and omnivores eat both.
- Predators are animals that eat a prey animal. Scavengers eat organisms that are already dead. Decomposers break down dead plants and animals into component parts, including nutrients.
- Relationships between species can be one of competition or one of symbiosis, in which one or both species benefits. Mutualism, commensalism, and parasitism are the three types of symbiotic relationships.
Vocabulary
- carnivore: Animals that only eat other animals for food.
- competition: A rivalry between two species, or individuals of the same species, for the same resources.
- consumer: An organism that uses other organisms for food energy.
- decomposer: An organism that breaks down the tissues of a dead organism into its various components, including nutrients, that can be used by other organisms.
- herbivore: An animal that only eats producers.
- omnivore: An organism that consumes both producers and other consumers for food.
- predator: A symbiotic relationship between two species in which one species benefits and one species is harmed.
- prey: An animal that could be killed and eaten by a predator.
- producer: An organism that converts energy into chemical energy that it can use for food. Most producers use photosynthesis but a very small number use chemosynthesis.
- scavenger: Animals that eat animals that are already dead.