Unit 1

• Scientific Method

Scientific Method: a process of investigation where problems are identified and their explanations are tested by carrying out experiments.

Observation: An unbiased, accurate report of an event.

Hypothesis: An educated guess based on observations.

Experiment: An experiment is designed to test a hypothesis.

Data: Consists of measurements, observations/information gathered during an experiment.

Replicate: A repeat of an experiment.

Control: A comparison used to provide a standard against which the actual experiment can be judged.

Theory: A hypothesis that has been supported by different experiments.

Principle/Law: A theory that has shown to be valid against long-term testing.

Ethics: Refers to whether issues are right or wrong

• Characteristics of Life

Continuity of life: Living things that arise from other living things of the same type (Biogenesis)

Metabolism: Sum of all the chemical reactions in an organism.

Characteristics of life: The common features shared by living organisms.

Organisation: Living things are composed of cells, tissues,organs and organ systems.

Nutrition: Process by which an organism obtain and uses food.

Excretion: Removal of waste products of metabolism.

Response: The reaction of organisms to stimuli in their environment.

Reproduction: The production of new individuals.

• Nutrition

Biomolecules: Molecules found in living things are composed of atoms where elements bonded together in different ratios to form biomolecules. Such as Carbohydrates, Lipids, Proteins and Vitamins.

Organic Compounds: Carbon atoms bonded together make up most of the chemical compounds in living things.

Monosaccharides: Single sugar molecules such as Glucose.

Disaccharides: 2 sugar molecules bonded together such as Sucrose, Lactose and Maltose.

Polysaccharides: Made up of many sugar molecules bonded together. Eg Starch, Glycogen and Cellulose

Phospholipids: Fat-like substances where one of the fatty acids is replaced/added a phosphate group.

Anabolic reactions: Convert smaller molecules into larger ones. (Using energy)

Catabolic reactions: Complex molecule is broken down to simple molecules. (Releasing energy)

• Ecology

Ecology: The study of the relationships of living organisms with one another and with the environment.

Ecosystem: A community of organisms and their abiotic environment.

Biosphere: Part of the earth in which life can occur.

Habitat: Place in the environment where an organism lives.

Population: All the member of the same species living in an area.

Community: Plants and animals sharing the resources of a particular habitat.

Niche: The functional role of an organism in an ecosystem. Eg How it feeds, what it eats, who eats it etc.

Abiotic Factors: Non-living factors.

Biotic Factors: Living Factors.

Climatic Factors: Refers to weather over a long period of time.

Edaphic factors: Aspects of the soil that influence an ecosystem such as the soil pH, soil type, moisture, air and mineral content of soil.

Producers: Autotrophs that carry out photosynthesis.

Consumers: Organisms that take in food from another organisms.

Primary Consumers: Organisms which feed directly on producers. Eg Rabbits

Secondary Consumers: Carnivores that feed on primary consumers. Eg Fox

Tertiary Consumers: Carnivores that feed on secondary consumers. Eg Badger

Food chain: The pathway along which energy is transferred in an ecosystem.

Food web: 2 or more interlinked food chains.

Trophic level: Is a feeding stage/energy level in a food chain.

Pyramid of numbers: Based on numbers of organisms at each trophic level in a food chain.

Nutrient recycling: The way in which elements (Carbon and Nitrogen) are exchanged between the living and non-living components of an ecosystem.

Nitrogen Fixation: Conversion of nitrogen gas into ammonia (NH3), ammonium (NH4+) or nitrate (NO3-)

Nitrification: The ammonia is converted to nitrites and then to nitrates by nitrifying bacteria.

Denitrification: Conversion of nitrates to nitrogen gas. It is carried out by denitrifying bacteria in the soil.

Pollution: Any harmful addition to the environment.

Pollutants: Substances that cause the undesirable change to the environment.

Conservation: The wise management of our natural resources.

Competition: Occurs when organisms actively struggle for a resource that is in short supply.

Intra-specific competition: This takes place between members of the same species. Eg Buttercups compete with each other for light,water and minerals.

Inter-specific competition: Occurs between members of different species. Eg Foxes and thrushes compete for earthworms.

Contest competition : Involves an active physical contest between 2 individuals. Eg Robins actively defend a territory for feeding, nesting and reproduction.

Scramble competition: Involves all the competing organisms getting some of the resources. Eg Seedlings competing for space around parent plant.

Adaptations: Ways in which organisms are specialised either in structure/behavior to survive competition.

Predation: An organism that lives by killing and consuming other living things. Eg Ladybirds kill greenfly.

Parasitism: Living organism that feeds on another living organism of a different species knows as host, generally causing harm to the host.

Ectoparasites/Exoparasites: Live on the body of the host. Eg greenfly on rose bushes.

Endoparasites: Live on the inside of the body of the host. Eg Disease causing bacteria in the human body (Streptococcus)

Symbiosis: Relationship between 2 organisms of different species that live in close association to the benefit of both organisms.

Saprophytes: Lives on dead organisms.

Quantitative study: A study to find out the number of organisms that exist in an ecosystem.

Qualitative study: A study to find out the type(s) of organism that exist in an ecosystem.