Life, Diversity & Classification Lecture Notes

Flashcards covering the foundational concepts of Life Sciences Grade 8, including characteristics of life, photosynthesis, respiration, classification, and viruses.

Biology (Life Sciences)

The study of life, or more precisely, living organisms.

Homeostasis

Regulation of the internal environment to maintain a constant state, like constant internal temperature, constant carbon dioxide level, or constant sugar levels.

Cell

The smallest unit of life; living organisms can be composed of one or more of these.

Unicellular

Organisms that consist of only one cell.

Multicellular

Organisms that consist of many cells.

Tissues

Many similar cells grouped together performing the same function, such as bone, muscle, or nerve tissue.

Organs

Several different types of tissue grouped together to form a structure, such as an eye, heart, kidney, or leaf.

Systems

Different organs grouped together to form a functional complex, such as the digestive or circulatory system.

Metabolism

Includes photosynthesis, nutrition, respiration, and excretion; processes that require energy to maintain internal organization.

Anabolism

The process of producing larger molecules, like sugars, from smaller molecules like water and carbon dioxide.

Catabolism

The process of breaking large molecules down into smaller ones.

Growth

The increase in size of an organism in all its parts due to an increase in the number of cells and/or the size of the cells.

Adaptation

The ability of an organism to change over a period of time in response to the environment, which is fundamental to evolution.

Response to stimuli

The ability of organisms to detect a change in their environment and then respond, often expressed by motion.

Reproduction

The ability to produce new organisms, occurring either asexually from a single parent or sexually from at least two parents.

Chemical potential energy

Also called food, this is the form of energy sunlight must be converted into before a living organism can use it.

Photosynthesis

The process where chlorophyll-containing organisms use water, carbon dioxide, and radiant energy from the Sun to make glucose and release oxygen.

Producers

Organisms that are able to produce food from sunlight energy, including plants, certain bacteria, and protists like phytoplankton.

Respiration

The process whereby energy-rich molecules like glucose are broken down gradually to release chemical potential energy.

ATP (adenosine triphosphate)

The form of energy that cells can use, released from food in special cell structures.

Chlorophyll

A green pigment needed to absorb sunlight energy, essential for the process of photosynthesis.

Stomata

Tiny openings on the leaves of land plants that allow carbon dioxide to enter and oxygen to be released.

Chloroplasts

Organelles in green leaves and stems that contain chlorophyll and enzymes necessary for photosynthesis.

Starch

A larger insoluble molecule used by plants to safely store glucose.

Mitochondria

The organelles found in all organisms except bacteria that serve as the site of respiration.

Metabolic water

Water formed as an end product of respiration, which is a vital water source for many desert animals like camels.

Biodiversity

The huge variety of plants, animals, and other organisms that exist on Earth, including where they live and their interrelationships.

Classify

To sort things so that those with the same or similar characteristics are grouped together.

Characteristic

A feature of something that helps us to recognize it as different from something else.

Taxonomy

The process of grouping organisms and giving names to the groups, used to build "The Tree of Life."

Binomial system

The two-part scientific naming system developed by Carl Linnaeus where names are written in Latin.

Species

A group of living organisms in the same habitat that look alike and can reproduce with each other to produce fertile offspring.

Genus

A category that groups species that are closely related, such as the group containing dogs, wolves, and coyotes.

Eukaryotes

Organisms containing a true nucleus surrounded by a nuclear membrane.

Fungi

Heterotrophic organisms that feed on dead decaying matter and have cell walls made of chitin.

Monera

Prokaryotic organisms, such as bacteria, that lack a true nucleus and have cell walls made of peptidoglycan.

Archaea

A domain of single-celled prokaryotes that lack peptidoglycan in their cell walls and often live in extreme environments.

Methanogens

The largest group of Archaea, responsible for producing methane gas in wetlands and the guts of animals.

Extremophiles

Microbes that require extreme conditions of temperature, salinity, or pH to survive.

Thermophiles

A type of extremophile that requires temperatures above $45^{\circ}\text{C}$ to survive.

Halophiles

Microbes that colonize highly saline environments and require salinity $> 9\%$ to maintain cell wall integrity.

Viruses

Akaryotic entities consisting of nucleic acid (DNA or RNA) and a protein coat, which can only reproduce inside a host cell.

Capsid

The protective protein coat surrounding the nucleic acid of a virus.

Obligatory parasites

Organisms that have no choice but to be parasitic, highjacking a host cell to perform metabolic processes.

Endemic

A disease only found among a particular group of people or in a local region.

Epidemic

A disease that occurs in many individuals in a community at the same time.

Pandemic

A disease that affects many people across the world.

Vector

An organism, such as a mosquito, flea, or tick, that carries a disease-causing agent from one organism to another.

Herd immunity

A state where enough people in a community are immune to a disease, preventing it from spreading through the population.