Classification, Variation and Inheritance

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Here I'll link up any posts to do with Classification, Variation and  Inheritance.
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Classification

Vertebrates and Invertebrates

Species

Variation

Variation: PCA

Reasons for Variety

Evolution

Genes

Explaining Inheritance

Genetic Disorders



What you should be able to do:


EDEXCEL GCSE Science BIOLOGY UNIT B1 Influences on life
Topic 1 Classification, variation and inheritance
  • 1.1 You must be able to demonstrate an understanding of how biologists classify organisms according to how closely they are related to one another including:
    • a) Species – groups of organisms that have many features in common
    • b) Genus – contains several species with similar characteristics
    • c) Family – comprising of several genera
    • d) Order – comprising of several families
    • e) Class – comprising of several orders
    • f) Phylum – comprising of several classes
    • g) The Five Kingdoms – animalia, plantae, fungi, protoctista and prokaryotes
  • 1.2 Be able to describe the main characteristics of the five kingdoms including:
    • a) Animalia – multicellular, do not have cell walls, do not have chlorophyll, feed heterotrophically
    • b) Plantae – multicellular, have cell walls, have chlorophyll, feed autotroprically
    • c) Fungi – multicellular, have cell walls, do not have chlorophyll, feed saprophytically
    • d) Protoctista – unicellular, have a nucleus
    • e) Prokaryotes – unicellular, have no nucleus
  • 1.3 Be able to explain why scientists do not classify viruses in any of the five kingdoms and regard them as non-living.
  • 1.4 Be able to describe the main characteristics of the phylum Chordata as animals with a supporting rod running the length of the body, an example of this being the backbone in vertebrates.
  • 1.5 Be able to explain how scientists place vertebrates into groups based on:
    • a) Oxygen absorption methods – lungs, gills and skin
    • b) Reproduction – internal or external fertilisation, oviparous or viviparous
    • c) Thermoregulation – homeotherms and poikilotherms
  • 1.6 Be able to demonstrate an understanding of the problems associated with assigning vertebrates to a specific group based on their anatomy and reproduction methods and why many vertebrates are difficult to classify
  • 1.7 Be able to discuss why the definition of a species as organisms that produce fertile offspring may have limitations: some organisms do not always reproduce sexually and some hybrids are fertile
  • 1.8 HT only: Be able to explain why binomial classification is needed to identify, study and conserve species, and can be used to target conservation efforts
  • 1.9 Be able to explain how accurate classification may be complicated by:
    • a) variation within a species
    • b) HT only: hybridisation in ducks
    • c) HT only: ring species
  • 1.10 Be able to construct and use keys to show how species can be identified.
  • 1.11 Be able to explain how organisms are adapted to their environment and how some organisms have characteristics that enable them to survive in extreme environments, including deep-sea hydrothermal vents and polar regions
  • 1.12 Be able to demonstrate an understanding of Darwin’s theory of evolution by natural selection including:
    • a) variation – most populations of organisms contain individuals which vary slightly from one to another,
    • b) over-production – most organisms produce more young than will survive to adulthood,
    • c) struggle for existence – because populations do not generally increase rapidly in size there must therefore be considerable competition for survival between the organisms,
    • d) survival - those with advantageous characteristics are more likely to survive this struggle,
    • e) advantageous characteristics inherited – better adapted organisms are more likely to reproduce successfully passing on the advantageous characteristics to their offspring
    • f) gradual change – over a period of time the proportion of individuals with the advantageous characteristics in the population will increase compared with the proportion of individuals with poorly adapted characteristics, and the poorly adapted characteristics may eventually be lost.
  • 1.13 Be able to describe and understand that variation can be continuous or discontinuous.
  • 1.14 Appreciate the variations within a species to illustrate continuous variation and discontinuous variation.
  • 1.15 Be able to interpret information on variation using normal distribution curves
  • 1.16 Be able to demonstrate an understanding of the causes of variation, including:
    • a) genetic variation – different characteristics as a result of mutation or reproduction
    • b) environmental variation – different characteristics caused by an organism’s environment (acquired characteristics)
  • 1.17 HT only: Demonstrate an understanding of how speciation occurs as a result of geographic isolation
  • 1.18 Be able to explain how new evidence from DNA research and the emergence of resistant organisms supports Darwin’s theory
  • 1.19 Be able to explain the role of the scientific community in validating new evidence, including the use of:
    • a) scientific journals
    • b) the peer review process
    • c) scientific conferences
  • 1.20 Be able to describe the structure of the nucleus of the cell as containing chromosomes, on which genes are located.
  • 1.21 You must understand that genes exist in alternative forms called alleles which give rise to differences in inherited characteristics.
  • 1.22 Know the meaning of, and use appropriately, the terms: dominant, recessive, homozygous, heterozygous, phenotype and genotype.
  • 1.23 Be able to analyse and interpret patterns of monohybrid inheritance using a genetic diagram, Punnett squares and family pedigrees.
  • 1.24 Be able to calculate and analyse outcomes (using probabilities, ratios and percentages) from monohybrid crosses.
  • 1.25 Be able to describe the symptoms of the genetic disorders:
    • a) sickle cell disease
    • b) cystic fibrosis
  • 1.26 HT only: Be able to evaluate the outcomes of pedigree analysis when screening for genetic disorders:
    • a) sickle cell disease
    • b) cystic fibrosis

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