Year 9 Ecology and Biology Exam

Ecology

The study of ecosystems.

Ecosystem

A collection of living things that interact with each other and their environment.

Biotic

Living factors in an ecosystem, such as plants and animals.

Abiotic

Non-living factors in an ecosystem, such as water, light and temperature.

Food chain

One feeding pathway showing the transfer of matter and energy.

Food web

Several connected food chains showing feeding relationships in an ecosystem.

Producer

An organism that makes its own food, usually by photosynthesis; also called an autotroph.

Consumer

An organism that gets energy by eating other living things; also called a heterotroph.

Primary consumer

A consumer that eats producers.

Secondary consumer

A consumer that eats primary consumers.

Tertiary consumer

A consumer that eats secondary consumers.

Herbivore

An animal that eats producers such as plants.

Carnivore

An animal that eats other animals.

Omnivore

An animal that eats both plants and animals.

Predator

An organism that hunts and eats another organism.

Prey

The organism that is hunted and eaten by a predator.

Symbiosis

An interaction between organisms of different species in which at least one organism benefits.

Mutualism

A symbiotic relationship where both organisms benefit.

Commensalism

A symbiotic relationship where one organism benefits and the other is not affected.

Parasitism

A symbiotic relationship where one organism benefits and the other is harmed.

Competition

When organisms compete for limited resources such as food and shelter.

Intraspecific competition

When organisms from the same species compete for limited resources such as mates, food and shelter.

Interspecific competition

When organisms of different species compete for limited resources such as food and shelter.

Matter

Anything that has mass and takes up space.

Energy

What organisms need to power bodily functions and activities.

Energy transformation

Energy changing from one form into another.

Carbon cycle

The continual movement of carbon through ecosystems.

Photosynthesis

Plants trap energy from the Sun and use it to convert carbon dioxide and water into high-energy glucose; oxygen is released.

Chloroplast

An organelle in plant cells where photosynthesis occurs.

Cellular respiration

The process that breaks down glucose to release usable energy as ATP.

Mitochondria

Organelles in plant and animal cells where cellular respiration occurs.

Aerobic respiration

Cellular respiration that releases energy from glucose using oxygen.

Anaerobic respiration

Respiration that releases energy from glucose without oxygen.

Fermentation

A type of anaerobic respiration.

Reactants

The starting substances in a chemical reaction.

Products

Substances formed in a chemical reaction.

Overfishing

Removing fish from a population faster than it can reproduce, reducing fish numbers.

Agricultural runoff

Water flowing off farmland carrying substances such as fertilisers and pesticides into waterways.

Microplastic

A very small piece of plastic, typically less than 5 mm, found in the environment.

Carrying capacity

The maximum population size an environment can support with available resources.

Biodiversity

The variety of living organisms in an area.

Resilient ecosystems

Ecosystems able to recover from disturbances while maintaining their essential functions.

Nervous system

The body system that senses the environment and controls actions.

Central nervous system (CNS)

The brain and spinal cord.

Peripheral nervous system (PNS)

Bundles of nerves that relay messages between sense organs, the CNS, muscles and glands.

Brain stem

Relays messages to and from the brain.

Cerebellum

The “little brain”; responsible for autopilot once you have learnt a new skill.

Cerebrum

The “thinking brain”; responsible for higher-order thinking and perception.

Neuron

A cell that transmits information as electrical signals to and from the CNS.

Cell body

Part of a neuron where the nucleus is located.

Dendrite

A branch of a neuron that receives messages.

Axon

Part of a neuron that carries impulses towards the axon terminals.

Myelin sheath

A fatty insulating layer around the axon.

Sensory neuron

Transmits messages from sensory organs to the CNS.

Interneuron

Transmits messages between sensory and motor neurons.

Motor neuron

Transmits messages from the CNS to effectors such as muscles and glands.

Voluntary response

An action we are aware of and can influence, such as moving limbs or writing.

Involuntary response

An automatic bodily action not consciously controlled, such as heartbeat or digestion.

Reflex arc

A rapid pathway that produces a protective response without waiting for conscious processing.

Stimulus-response pathway

A series of events in the nervous system leading to a response: stimulus, receptor, co-ordinator, effector, response.

Stimulus

A detectable change in the environment that elicits a response.

Receptor (sensory)

A specialised structure that detects a type of stimulus.

Chemoreceptor

Detects chemicals such as odour molecules; found in nose and tongue.

Mechanoreceptor

Detects touch, pressure, sound and motion; found in skin, inner ear and muscles.

Thermoreceptor

Detects temperature changes; located in the skin.

Pain receptor

Detects chemical changes in damaged cells; found throughout the body, mainly the skin.

Photoreceptor

Detects light; found in the eye, especially the retina.

Synapse

A gap or junction between two neurons.

Neurotransmitter

A molecule enabling signal transmission across a synapse.

Co-ordinator

Usually the brain or spinal cord; receives information from sensory neurons.

Effector

A muscle or gland that produces a response.

Hormone

A chemical messenger produced by an endocrine gland and released into the bloodstream to target cells.

Gland (endocrine)

A structure that produces and releases hormones into the bloodstream.

Receptor (hormone)

A specially shaped structure on a target cell that matches a particular hormone.

Target cell

A cell with a complementary-shaped receptor for a particular hormone.

Pineal gland

An endocrine gland associated with melatonin, which regulates the sleep-wake cycle. [Supplementary detail]

Adrenal gland

A gland above the kidneys that releases adrenaline.

Testicles

Male reproductive organs that produce sperm and the hormone testosterone. [Supplementary detail]

Pituitary gland

The “master gland” in the brain; releases hormones including growth hormone, TSH and FSH.

Pancreas

The organ that releases insulin and glucagon to regulate blood glucose.

Thyroid gland

A gland in the neck that releases thyroxine.

Homeostasis

The body’s ability to maintain a stable internal condition despite external changes.

Insulin

Hormone released by the pancreas when blood glucose is high; lowers blood glucose.

Glucagon

Hormone released by the pancreas when blood glucose is low; raises blood glucose.

Blood glucose

The amount of glucose (sugar) in the blood.

Diabetes

A non-infectious disease involving problems regulating blood glucose. [Supplementary definition]

Adrenaline

Hormone that increases heart rate, slows digestion and makes energy available to muscles.

Thyroxine

Hormone that increases the use of oxygen and nutrients by cells and increases body temperature.

Growth hormone

Pituitary hormone that regulates growth during childhood.

TSH

Thyroid-stimulating hormone; stimulates thyroid hormone production.

FSH

Follicle-stimulating hormone; stimulates egg and sperm production.

Melatonin

Hormone that regulates the sleep-wake cycle.

Microbe

An organism that can only be seen with a microscope, such as bacteria or fungi.

Pathogen

A microbe that causes disease.

Bacteria

Unicellular microbes made of small, simple cells without a nucleus.

Virus

A non-cellular infectious agent containing genetic material in a protein or fat layer; reproduces in host cells.

Fungi

Microbes with complex cells; may be unicellular or multicellular; some feed on hosts and produce toxins.

Outbreak

A sudden increase in cases of an infectious disease in a particular place.

Infection

When pathogens enter the body and multiply.

Disease

A condition in which symptoms appear; infectious diseases may result from pathogen damage.