5.2, 5.3 and 5.4 Definitions Flashcards
Distribution
The area inhabited by a plant or animal species.
Density
The number of a species living within an area.
Ecosystem
Communities of organisms that interact with each other and their environment.
Biotic factors
The living things (organisms) in an ecosystem.
Abiotic factors
The non-living features in an ecosystem.
Tolerance range
Range of an abiotic factor in the environment in which an organism can survive.
Optimum range
The range, within a tolerance range for a particular abiotic factor, in which an organism functions best.
Biodiversity
The variety of species of biological organisms, often in relation to a particular area.
Sampling methods
Techniques used to determine the density and distribution of various populations and communities within an ecosystem.
Transects
A sampling area along a straight line in which the number of organisms in that area is counted and recorded.
Quadrats
A sampling area, often one square metre, in which the number of organisms in that area is counted and recorded.
mark, release and recapture
A sampling method used to determine the abundance of mobile species.
Root hairs
Tube-like outgrowths of cells on the surface of roots. They have thin walls, which allow water and dissolved substances to move into the root.
Phloem
Long, narrow, living cells that are joined together to form long tubes in a plant. The tubes move the food made in the leaves to other parts of the plant, such as the roots and storage areas.
Xylem vessels
Long narrow cells that are joined together to form long tubes in a plant. The tubes, made from xylem cells, move water and dissolved minerals up from the roots to the stem and leaves. The wood in a tree trunk consists mostly of dead xylem cells.
Vascular bundles
Group of xylem and phloem vessels within a plant stem.
Translocation
Transport of materials, such as water and glucose, in plants.
Transpiration stream
Movement of water through a plant as a result of loss of water from the leaves.
Transpiration
Loss of water from plant leaves through their stomata.
Organelles
Small structure in a cell with a special function.
Chloroplasts
Oval-shaped organelle found only in plant cells. Chloroplasts contain the pigment chlorophyll. They are the ‘factories’ in which carbon dioxide and water are changed by sunlight and water into food by the process of photosynthesis.
Chlorophyll
The green-coloured chemical in plants that absorbs the light energy used in photosynthesis, which makes food from carbon dioxide and water.
Light energy
Energy from the light of the sun, absorbed by plants and used in photosynthesis.
Glucose
A simple carbohydrate and the simplest form of sugar.
Flaccid
Limp, not firm.
Turgid
Firm, distended.
Stomata
Pores that exchange gases found on the surface of leaves. They are bordered by guard cells that change the size of the opening of the stomata.
Guard cells
Cells surrounding each stoma in a leaf enabling it to open or close depending on the availability of water.
Stoma
Small openings through which water transfer occurs, located mainly on the lower surface of leaves. These pores are opened and closed by guard cells. Plural = stomata
Flowers
The sexually reproductive structure of some plants.
Gametes
Sex cells.
Anthers
The part of a flower that produces pollen (the male gametes).
Pollen grains
The male gametes of a flower.
Ova
Female gametes (eggs) or sex cells.
Ovary
In plants, the hollow, lower end of the carpel containing the ovules (the female egg cells); in animals, the female organ that produces ova and reproductive hormones.
Fertilisation
Penetration of the ovum by a sperm.
Pollination
Transfer of pollen from the stamen (the male part) of a flower to the stigma (the female part) of a flower.
Stigma
The female part of a flower, at the top of the carpel, that catches the pollen during pollination.
Self-pollination
Transfer of pollen from the flower’s own stamen to its stigma.
Cross-pollination
Transfer of pollen from stamens of one flower to the stigma of a flower of another plant of the same type.
Wind pollination
Transfer of pollen from one flower to another by the wind.
Insect pollination
Transfer of pollen from one flower to another by insects.
Vectors
An organism that carries a pathogen between other organisms without being affected by the disease the pathogen causes; an organism that carries and disperses reproductive structures (e.g. pollen) of a different species.
Pollinators
Something that transfers pollen from one flower to another.
Autotrophs
See producer.
Producer
Organism at the base of the food chain that does not need to feed on other organisms; also known as an autotroph.
Photosynthesis
The food-making process in plants that takes place in chloroplasts within cells. The process uses carbon dioxide, water and energy from the sun.
