NZQA Biology AS 91603: Animal and Plant Survival

Factors of Survival

Keywords

Selection pressure: environmental (biotic and/or abiotic), interspecific (between species) or intraspecific (between same species)

  • selection pressure causes the evolution of species as it selects a particular trait (normally determined by genetics) that allows species to survive
  • it will lower the number of individuals of a species
    • e.g flies and their ability to fly faster → easily avoid insecticides sprayed by humans and are more likely to survive and pass on their genes

Adaptive advantage: an adaptation of an organism, either physiological/structural/behavioural

  • ensures their survival and reproduction
    • e.g flies and their small bodies → less energy needed to fly, less sound, hard to detect → easier to avoid predators and are more likely to survive and pass on their genes

Natural selection: an organism’s ability to survive and reproduce

  • an organism with better adaptations to the environment has a higher survival chance and more likely to pass on their genes

Genetic diversity: the number of alleles present in a gene pool

  • the larger the gene pool, the less impact genetic drift has
  • increases resilience of organism
    • e.g if the climate changes but no genes present to counter it in the gene pool, the species will die out
  • natural selection/selection pressure lowers the genetic diversity due to the selection on particular traits

Benefit vs. Cost

Organisms are selfish and most species will only choose an action that directly benefits themselves.

Energy vs. Cost

If there is more energy gain compared to expenditure, then the organism has a higher chance to survive.

  • movement - to avoid predators, find foods, find mate(s), find a habitat, etc.
  • reproduction - to find a mate among the intraspecific competition; any reproduction costs a lot of energy
  • defence - the higher the energy, the more strength you will have to defend yourself, your territory, and your offspring
  • growth - the bigger you are, the more likely you are to find a mate, gather food (to grow), and more likely to carry out photosynthesis (plants)

But in comparison, species also have altruistic behaviour. This is the helping of their own species or kin selection. This allows the survival of either a bloodline or species.

For example, pukeko families often have grandparents who will aid in the care of grandchildren. In penguins, they will look after other herds even if they are not directly related by blood.

Biogeography

Biogeography: the study of the patterns of geographic distribution of organisms and the factors that determine those patterns

Twenty million years ago, the Indian and Asian continental plates clashed and pushed up the massive Tibetan plateau.

  • the plateau acts as a huge heat engine in the summer as it absorbs solar energy and transfers it to the atmosphere
  • this causes immense convection currents
  • with the hot air rising, the air is sucked in from all around, including moist air from the Indian ocean → leads to the intense South East Asian monsoon season

As for New Zealand, the Zealandia continent began to separate from Gondwanaland around 80 million years ago.

Due to their close distance, Australia and New Zealand shared many species such as the moth family Hepialidae.

  • two hepialid lineages dispersed from Australia to New Zealand successfully over the past 4-5 million years (Brown et. al (1999))
    • this coincides with the uplift along the alpine fault

Colonization was find to have increased the genetic diversity in New Zealand following a range expansion of silvereye within the country which led to a reduction in allelic diversity.