biology igcse cambridge all topics

Subdecks (5)

Cards (2961)

  • Sensitivity
    The ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
  • Growth
    A permanent increase in size and dry mass by an increase in cell number or cell size or both
  • Excretion
    The removal from organisms of the waste products of metabolism, toxic materials and substances in excess of requirements
  • Nutrition
    The taking in of materials for energy, growth and development. Plants require light, carbon dioxide, water and ions. Animals need organic compounds and ions and usually need water
  • Autotrophs
    Photosynthetic plants that are usually the first organisms in food chains
  • Species
    A group of organisms that can reproduce to produce fertile offspring
  • Binomial system
    An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and the species
  • Organisms can be classified into groups by the features that they share
  • Classification systems aim to reflect evolutionary relationships
  • Classification is traditionally based on studies of morphology and anatomy
  • Binomial system
    The scientific name of an organism is made up of two parts showing the genus and the species
  • The sequences of bases in DNA and of amino acids in proteins are used as a more accurate means of classification
  • Organisms which share a more recent ancestor have base sequences in DNA that are more similar than those that share only a distant ancestor
  • Features in cells of all living organisms
    • Cytoplasm
    • Cell membrane
    • DNA as genetic material
    • Ribosomes for protein synthesis
    • Enzymes involved in respiration
  • Five kingdoms of classification
    • Animal
    • Plant
    • Fungus
    • Prokaryote
    • Protoctist
  • Animals
    • Multicellular organisms whose cells have no cell walls or chloroplasts
    • Most animals ingest solid food and digest it internally
  • Arthropods
    • Jointed limbs
    • Hard, firm external skeleton called a cuticle
    • Segmented bodies with flexible joints between segments
    • Distinct head, thorax and abdomen regions
  • Crustacea
    • Exoskeleton and jointed legs
    • Two pairs of antennae
    • Compound eyes
    • Jointed limbs on each body segment, modified on head segments
  • Insects

    • Segmented bodies with firm exoskeleton
    • Three pairs of jointed legs
    • Compound eyes
    • Two pairs of wings
    • Head, thorax and abdomen regions
    • Only one pair of antennae and three pairs of legs, no limbs on abdomen
  • Arachnids
    • Body divided into cephalothorax and abdomen
    • Four pairs of limbs on cephalothorax
    • Pedipalps used in reproduction
    • Chelicerae used to pierce and paralyse prey
    • Several pairs of simple eyes
  • Myriapods
    • Head and segmented body not obviously divided into thorax and abdomen
    • Pair of legs on each body segment, abdominal segments fused in pairs
    • One pair of antennae and simple eyes
  • Vertebrates
    • Have a vertebral column
    • Poikilothermic (cold-blooded) or homoiothermic (warm-blooded)
  • Fish
    • Poikilothermic (cold-blooded) vertebrates
    • Streamlined shape
    • Covered in overlapping scales
    • Have fins
    • Breathe through filamentous gills
    • Reproduce sexually with external fertilisation
  • Homoiothermic

    Constant temperature
  • Internal regulatory mechanisms keep the body temperature within narrow limits
  • Fish
    • Poikilothermic (cold blooded) vertebrates
    • Smooth, streamlined shape
    • Covered with overlapping scales
    • Have fins
    • Breathe through filamentous gills
    • Reproduce sexually with external fertilisation
  • Amphibia
    • Poikilothermic (cold blooded) vertebrates
    • Have four limbs and no scales
    • Spend part of life in water and part on land
    • Moist skin with capillaries to exchange gases
    • Have lungs but no diaphragm or ribs
    • Reproduce with external fertilisation
  • Reptiles
    • Land-living vertebrates
    • Dry, scaly skin that resists water loss
    • Lay eggs with tough, parchment-like shells
    • Can regulate temperature to some extent by basking in the sun
  • Birds
    • Homoiothermic (warm blooded) vertebrates
    • Flexible vertebral column in neck, rest fused for rigid structure
    • Covered in feathers of different types
    • Have four limbs, with forelimbs modified into wings
    • Have beaks
    • Reproduce with internal fertilisation and lay hard-shelled eggs
  • Mammals
    • Homoiothermic (warm blooded) vertebrates
    • Have hair rather than feathers
    • Have a diaphragm for breathing
    • Have mammary glands to produce milk for young
    • Give birth to live young rather than laying eggs
    • Undergo internal fertilisation and development in the uterus
  • Ferns are land plants with quite highly developed structures, including stems, leaves, roots, vascular tissue, and multicellular roots
  • Ferns
    • Produce gametes but no seeds
    • Reproduce by producing single-celled spores from sporangia on the leaves
  • Monocotyledons
    Flowering plants with only one cotyledon in their seeds, often with long, narrow leaves and parallel leaf veins
  • Dicotyledons
    Flowering plants with two cotyledons in their seeds, often with broad leaves and branching leaf veins
  • Most fungi are made up of thread-like hyphae rather than cells, and have many nuclei distributed throughout the cytoplasm
  • Bacteria are single-celled organisms with a cell wall made of proteins, sugars and lipids, and a single circular chromosome not enclosed in a nuclear membrane
  • Protoctists are single-celled organisms with their chromosomes enclosed in a nuclear membrane
  • Some protoctists, like Euglena, have chloroplasts and can photosynthesize, while others, like Amoeba and Paramecium, take in and digest solid food
  • Circular strand of DNA
    • Not enclosed in a nuclear membrane
    • Coiled up to occupy part of the cell
  • Individual bacteria
    • May be spherical, rod-shaped or spiral
    • Some have filaments called flagella projecting from them
    • Flagella can flick and move the bacterial cell about