Module Three Flashcards
What is an ecosystem?
The combinations of all organisms living in a community, their interactions and all the non-living features with which they interact.
What is a selection pressure?
Factors that exist in an environment that make it easier for some organisms to survive and others less likely.
What are examples of abiotic selection pressures?
temperature, soil type, water availability.
what are examples of biotic selection pressures?
competition, predator-prey
Why is biodiversity essential for survival?
Variation within population allows for evolution in the case of a geological change. Organisms with a variation that help them survive is passed onto their offspring and becomes the common phenotype in their population. Without variation the species would become extinct.
What is a selecting agent?
The specific environmental factor that is responsible for a selection pressure.
What effect has the cane toad had on the red bellied black snake?
The average head size of these snakes has decreased. This is due to the fact that consuming larger cane toads means consuming more poison.
What environment impact did the cane toad have on Australia?
- Caused declines in native predators, such as kookaburras, northern quolls and goannas, which die after ingesting the toad. The cane toad also competes with native species for shelter, space and food resources.
- Pose a risk to human and domestic pet health, due to their highly poisonous skin secretions.
- Indigenous Australians using traditional food sources have also been affected because native species numbers have declined.
What is a structural adaptation?
Adaptations that are physical features of an organism that enables them to survive in their environment.
What effect has the cane toad had on the quoll?
They have experienced a dramatic population decline as the quoll’s are continuously consuming the toad.
What is an adaptation?
Features that enable organisms to survive and reproduce. They are the result of the evolutionary process of natural selection, in which those organisms that are best suited to their environment survive and reproduce, passing on their advantageous traits to their offspring.
Gives examples of a structural adaptation.
- the thumb in primates.
- the blubber in a whale
- fleshy stems
What is a behavioural adaptation?
Adaptation that refers to those actions performed by an organisms in response to a stimulus that improves their chance of survival.
Give examples of behaviour adaptations.
- bats huddling on the roof of a cave.
- being nocturnal
What is a physiological adaptation?
An adaptation that consist of processes involved in an organism carrying out its function.
Give examples of physiological adaptations.
- Koalas are able to survive on gum leaves even though they contain little nutrition, because they have a very low metabolic rate, which allows them to retain food in their digestive system for a very long time. Their low metabolic rate is an example of a physiological adaptation.
- Rattlesnakes produce venom, which is a highly modified saliva. This venomous saliva is a physiological adaptation for immobilising their prey.
What is a movement and behavioural adaptation?
These are actions that an organisms takes in improve survival or reproduction.
What are the three types of tropism?
- Phototropism: growth in response to light.
- Chemotropism: growth in response to chemicals.
- Geotropism: growth in response to gravity.
Outline the process of natural selection.
Individuals in a population have natural variation, these variation means some individuals have traits better suited to the environment than others, individuals with adaptive traits are more likely to survive and reproduce and pass their advantageous traits onto their offsrping.
