Grade 8 Life Sciences: Microorganisms, Ecosystem Conservation, and Disease

Vocabulary practice flashcards covering microorganisms, bacterial and fungal structures, disease transmission and prevention (such as cholera and malaria), ecosystem services, and conservation management.

Cholera

An infectious intestinal disease caused by the bacterium Vibrio cholerae, which causes severe watery diarrhoea and vomiting that can lead to dangerous dehydration.

Oral Rehydration Solution (ORS)

An effective cholera treatment designed to replace the vital water and salts lost through excessive diarrhoea and vomiting.

Biodiversity

The variety of living organisms and their varied habitats.

Monocultures

Single crop species planted over vast, uniform areas, which replace diverse habitats and create ecosystems with extremely low biodiversity.

Alien Species

Exotic species that are not indigenous (native) to a specific area and often outcompete indigenous wildlife and plants for food and living space.

Sustainable Use

The wise, selective harvesting and management of natural resources so that sufficient parent populations remain to regenerate naturally without depletion.

Biological Control

The population control of invasive alien species using imported living natural enemies (such as natural predators, insects, or fungi) from their native regions, such as using a specialized weevil against the red sesbania plant.

Integrated Alien Management

The recommended practice of combining biological, chemical, and mechanical control methods simultaneously to successfully manage invasive alien plant populations.

Wetlands

Natural hydrological systems including marshes, floodplains, lakes, and estuaries that naturally filter water, store rainfall, check soil erosion, and offer breeding grounds; South Africa has lost over $50\%$ of them.

Microorganisms

Tiny living organisms—either unicellular or multicellular—that cannot be seen with the naked eye and require a microscope for observation.

Fungi

One of the five kingdoms of living things containing the largest microorganisms (including yeast, bread mould, and mushrooms), which can sometimes be seen without a microscope.

Malaria

Disease caused by the protist Plasmodium, carried by anopheles mosquito

Bacterial Shapes

The three primary morphological forms exhibited by bacteria: rod-like shape, spherical shape, and spiral shape.

Viruses

Non-cellular microscopic infectious agents that cannot survive or reproduce outside a host body, including pathogens such as Human Immunodeficiency Virus and SARS-CoV-2.

Protists

Organisms from one of the five kingdoms of living things that can exhibit plant-like or animal-like characteristics, including Plasmodium which causes malaria.

Pathogens

Disease-causing microorganisms that can infect living organisms and disrupt biological processes.

Tuberculosis

Respiratory disease caused by a bacteria, and is spread when an infected person coughs or sneezes into the air

Diseases caused by fungi?

Ringworm and athletes foot

Pasteurisation

A food preservation process where milk is heated to approximately $70\,^{\circ}\text{C}$ for $15$ to $30\text{ seconds}$ and then rapidly chilled to destroy harmful microbes and prevent spoilage.

Decomposers (Detritivores)

Organisms such as bacteria, fungi, and insects that consume dead plants, dead animals, and animal waste, breaking them down to release vital nutrients back into the soil.

What would happen if decomposers were removed from the food chain?

dead plants, animals and waste would build up in the environment. Nutrients would not return to the soil, causing plants to grow less. This would disrupt food chains, decrease animal populations and could eventually lead to ecosystem collapse

Photosynthesis

The process by which plants use sunlight to make glucose (food)

Respiration

The chemical reaction that occurs in cells of all living organisms to release energy from food (glucose)

Carbon cycle

The movement of carbon between the atmosphere, plants, animals, soil, and oceans

Mitochondria

The “powerhouse of the cell” responsible for generating majority of the cell’s energy

Keystone Species

The species that plays an unusually large role in the functioning of the ecosystem, and removal of this species can lead to the destruction of the habitat, as the keystone species plays a large role in creating abundance of life and maintaining the health of many species

Indicator Species

An organism whose presence, absence, or abundance reflects the conditions of the environment. They are used as a signal of change for the biological condition of an area and are used to determine the overall health of an ecosystem

Adaptations

Characteristics given to organisms to help them survive in their environment

Structural/physical adaptation

Special physical feature if the body

Behavioural adaptation

Different behaviours animals have developed in order to survive within their environment

Functional/physiological adaptation

How the organism’s body functions to help it survive in its environment

Symbiosis

Relationship where two or more species live closely together. There is mutualism (+/+), commensalism (+/-), and parasitism (+/0).

Mutualism

Symbiosis where both species benefit from the relationship

Commensalism

One species benefits, the other is unharmed or unaffected

Parasitism

One species, the parasite, benefits at the expense of the other species, the parasite.

Ecological pyramids

Graphical representation of the tropic structure system. There is pyramid of numbers, pyramid or biomass, and pyramid of productivity

Pyramid of numbers

Graphic representation of the number of individuals per unit of area of various trophic levels. Large number of producers form the base, lower number if top carnivores occupy the top

Pyramid of biomass

Graphical representation of biomass present per unit of area at different trophic levels. Mass or each individual x no. of each individual at trophic kevels

Pyramid of productivity

Graphical representation of the flow of energy through each trophic level of a food chain over a fixed time period

Food chain

Linear sequence of organisms that shows how energy and nutrients move through an ecosystem

Food web

Visual way to show what the organisms in a habitat eat.