Biology

• Movement is an action by an organism causing a change of position or place.
• Respiration is the chemical reactions that break down nutrient molecules in living cells to release energy for metabolism.
• Sensitivity is the ability to detect and respond to changes in the environment.
• Growth is a permanent increase in size and dry mass by an increase in cell number or cell size or both.
• Reproduction is the processes that make more of the same kind of organism.
• Excretion is the removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements.
• Linnaeus named organisms in Latin using the binomial system where the scientific name of an organism is made up of two parts starting with the genus (always given a capital letter) and followed by the species (starting with a lower case letter).
• Organisms were first classified by a Swedish naturalist called Linnaeus in a way that allows the subdivision of living organisms into smaller and more specialised groups.
• All mammals have bodies covered in hair, feed young from mammary glands and have external ears (pinnas).
• The sequence of classification is: Kingdom, Phylum, Class, Order, Family, Genus, Species.
• When typed, binomial names are always in italics (which indicates they are Latin).
• The species in these groups have more and more features in common the more subdivided they get.
• Main features of all Prokaryotes include being often unicellular, having cells with cell walls (not made of cellulose) and cytoplasm but no nucleus or mitochondria.
• Main features of all Protoctists include being multicellular, having a nucleus, some may have cell walls and chloroplasts, and some photosynthesize and some feed on organic substances made by other living things.
• All plants are multicellular, have cells with a nucleus, chloroplasts and cellulose cell walls, feed by photosynthesis, and do not photosynthesize but feed by saprophytic or parasitic nutrition.
• Moulds, mushrooms, yeast are usually multicellular, have cells with nuclei and cell walls not made from cellulose, and feed by saprophytic or parasitic nutrition.
• Nutrition is the taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds, ions and usually need water.
• Invertebrates with jointed legs are classified into the following classes: Myriapods, Insects, Arachnids, and Crustaceans.
• All invertebrates with jointed legs are part of the phylum Arthropods.
• Identification of monocotyledons and dicotyledons comes up fairly frequently in the multiple choice paper, so it is worth learning the two differences between their flowers and leaves.
• Flowering plants reproduce sexually by means of flowers and seeds, and seeds are produced inside the ovary found at the base of the flower.
• Myriapods have a body that consists of many segments, each containing at least one pair of jointed legs and one pair of antennae.
• Insects have a three-part body consisting of a head, thorax, and abdomen, with three pairs of jointed legs and two pairs of wings.
• Wheat plants are monocotyledons, while sunflowers are dicotyledons.
• Arachnids have a two-part body consisting of a cephalothorax and abdomen, with four pairs of jointed legs and no antennae.
• Ferns have leaves called fronds and do not produce flowers but reproduce by spores produced on the underside of fronds.
• Flowering plants can be divided into two groups: monocotyledons and dicotyledons.
• Flowers from monocotyledons contain petals in multiples of 3, while flowers from dicotyledons contain petals in multiples of 4 or 5.
• One of the morphological characteristics used to classify invertebrates is whether they have legs or not.
• Ferns and flowering plants are examples of plants.
• Crustaceans have more than four pairs of jointed legs, a chalky exoskeleton formed from calcium, and breathe through gills.
• Prokaryotes are characterized by their cell composition and structure.
• Fungi, protoctists, and prokaryotes are characterized by their cell composition and structure.
• The base sequences in a mammal’s DNA are more closely related to all other mammals than to any other vertebrate groups.
• Studies of DNA sequences of different species show that the more similar the base sequences in the DNA of two species, the more closely related those two species are and the more recent in time their common ancestor is.
• Organisms can be classified based on their features, such as whether they have wings or legs, and their anatomy, which is the detailed body structure as determined by dissection.
• All animals are multicellular, their cells contain a nucleus but no cell walls or chloroplasts, and they feed on organic substances made by other living things.
• The cells of all protoctists contain the following: cytoplasm, cell membrane, and DNA as genetic material.
• The sequences above show that Brachinus armiger and Brachinus hirsutus are more closely related than any other species in the list as their DNA sequences are identical except for the last-but-one base (B.armiger has a T in that position whereas B.hirsutus has an A).
• The order of classification can be remembered by using this mnemonic: KING PHILIP CAME OVER FOR GRAND’S SPAGHETTI.