1 / 15

Populations & Variation

Populations & Variation. Populations. A population is a group of the same species living within a particular geographical area at a given time. Variation. Monomorphic Variation. Polymorphic Variation.

lana
Download Presentation

Populations & Variation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Populations & Variation

  2. Populations A population is a group of the same species living within a particular geographical area at a given time.

  3. Variation Monomorphic Variation Polymorphic Variation Members of a population may show two or more variations for a particular trait. Flower colour in lupins • Members of a population may show no variation for a particular trait. • Galahs are monomorphic in respect to plumage • As are sulphur crested cockatoos

  4. Variation Continuous Discontinuous

  5. Variation • Variation exists in members of a population. • Variation may be: • Structural • Biochemical • Physiological • Developmental • Behavioural • Geographic

  6. Structural Variation • Variation exhibited in members of a population in terms of one or more structural traits. • EG. Polydactyly in humans, tails (or lack of in cats, toe number in chickens.

  7. Biochemical Variation • Variation exhibited amongst members of a population of a biochemical trait. • EG. coloursof some animals are due to biochemical differences – budgerigars.

  8. Physiological Variation • Variation in a population of physiological traits in a population • EG. Ability to taste and smell certain compounds in foods or odours, ability to distinguish between colours

  9. Developmental Variation • Variations due to changes that normally occur during the life span of the species. • EG. Colour changes in pythons, magpies, silver gulls from juveniles to adults, ripening of fruit from green to red/dark (strawberries)

  10. Behavioural Variation • Difference in behaviour expressed in various traits. • EG. In dogs, retrieving, herding. In horses – natural trotters, or natural pacers.

  11. Geographic Variation • Members of a population may differ from those in another part. • EG. Tawny frogmouth birds are smaller and paler in northern parts of their range and larger and darker in southern parts.

  12. Causes of Variation • Genetic: • Polygenes and monogenes • Sexual reproduction:Recombination of alleles • Mutations – new alleles • Interactions with the environment • Environmental factors like soil pH, light, altitude,soilnutrients etc influence the phenotype

  13. Mutations • A mutation refers to any permanent change in the DNA nucleotide base sequence of an organism

  14. Can you inherit a mutation? • Yes! if a mutation occurs in the germline cells the change will be passed on to the offspring. • If a mutation occurs somatic cells it will not be inherited, but it may affect the individual during their lifetime.

More Related