Links to the idea that living things change in response to environmental changes. Explains how New Zealand birds have changed to suit their ecosystems/environments.
LOI 2: How living things respond to environmental changes, both natural and human-induced.
LOI 3: The balance between human interaction and the biodiversity in an ecosystem.
L4 Living World - Ecology: Explain how living things are suited to their particular habitat and how they respond to environmental changes, both natural and human-induced.
L5 Living World - Ecology: Investigate the interdependence of living things (including humans) in an ecosystem.
Key Concepts: Change, Connection
Related Concepts: Biodiversity, Sustainability
New Zealand separated from Gondwana around 65 million years ago. Due to the geographical isolation and a lack of ground-dwelling predators, our birds evolved unique characteristics. Flight was not required to escape predators, so birds such as the kiwi, takahē and (now extinct) moa adapted to these conditions by developing a large body size and loss of flight.
Adaptation is an evolutionary process whereby an organism becomes increasingly well suited to living in a particular habitat. These are changes that occur over many, many generations. It is definitely not a quick process!
Adaptations occur through natural selection. Organisms that have features better suited to their habitat will survive over successive generations, while those that are not well suited to the environment will not survive. Surviving species will then reproduce, producing more individuals within the population that have the same, favourable features for survival. Over many generations, more and more of the individuals within the species will have the favoured features until eventually all individuals will have them. Charles Darwin originally documented natural selection as a function of evolution in 1854 in his book On the Origin of Species.
Adaptations can result in the gain of a new or a modified feature that results in an advantage in the current environment, for example, a specialised beak. Adaptations can also result in the loss of a feature that no longer has a function in the current environment, for example, the loss of wing function when there is no need to fly.
Adaptations are many and varied, but they are generally grouped into 3 main categories: structural, behavioural and physiological.
Structural (or morphological) adaptations are changes to the physical features of the organism. These include things you can see, like its shape or body covering, as well as its internal organisation. These can occur in populations over many generations.
Here are a few of the ways New Zealand birds have adapted their physical features to suit a particular habitat:
Behavioural adaptations are learned or inherited behaviours that help organisms to survive. These can occur in populations within one or a few generations.
Here are a few of the ways that New Zealand birds have adapted their behaviour to suit a particular habitat:
Physiological adaptations relate to how an organism’s metabolism works. These adaptations enable the organism to regulate their bodily functions, such as breathing and temperature, and perform special functions like excreting chemicals as a defence mechanism. These can occur in populations over many generations.
Kererū are one of few birds to produce crop milk, a protein-rich milky secretion from the walls of the parents' crops. When mixed with fruit pulp, this sustains their chicks in the early stages of life.
Many New Zealand birds are poorly adapted to an environment that has changed greatly over time.
Their environment has changed enormously over the past 1000 years – primarily due to colonisation by human settlers. Humans introduced mammalian predators, cleared native bush, resulting in a loss of natural habitat for birds, and hunted birds as a food source.
Conservation efforts are required to protect native bird species that are currently endangered.
In this activity, students classify the different types of adaptations that New Zealand native birds have.