BP S1 Flashcards
What are elements that impact on the evolution of plants and animals?
- Physical conditions in the environment
- Chemical conditions in the environment
- And Competition for resources
Changes in physical conditions in the environment include….
Natural conditions, such as temperature and availability of water.
Approximately 25 million years ago, Australia was considerably….
Wetter than today, with large areas of rainforest.
The Australian landmass has become drier over time and this has led to the change in the species of…
Kangaroos.
During the time of the rainforests in Australia what were the kangaroos like?
Small, omnivorous with unspecialised teeth, eating a variety of foods from the forest floor.
Food was abundant, there was no need for specialised grinding teeth.
As Australia became more arid and grass became the dominant vegetation in some areas, environmental selective pressure resulted in larger kangaroos favouring teeth suitable for grass. Describe these teeth.
High crested molars, efficiently grind low nutrition grass into a more easily digestible paste. Slicing pre molars have been reduced.
Changes in physical conditions such as climate and exposure to fire have led to the evolution changes of…
Australian Flora.
As Australia drifted north over the 20million years the climate has become…
More seasonal, drier and hotter.
Name some species on Australia that have been restricted to small pockets due to Australia’s evolutionary climate change.
The Antarctic Beech and the Wollemi pine.
A very old plant family known as the “Myrtacae” has diversified significantly and become more prolific name some examples.
Eucalypts, bottle brushes, tea trees and lilly-pillies.
Name the areas the primitive “Myrtacae” are found and where they are found in present day Australia.
Primitive forms still exist in moist rainforest climates but the specialised present day ones evolved into the very dry, highly seasonal and fire prone regions.
It is believed that the first kangaroos lived in trees but as a result of climate change, kangaroos evolved….
Into many forms we see today.
The primary cause of evolution is a change in environment. however variations in the genetic makeup of organisms must also occur.
The environment has three major ways in which it can change, name them.
- The physical environment eg temp, light
- The chemical environment eg salinity, acidity
- competition for limited resources.
Give an example of a change in physical condition and how it is an effector in evolution.
Heat.
As an environment heats up, larger organisms with a smaller SA:Vol ratio have more difficulty cooling down and their bodies are more likely to suffer heat stress. while the organisms smaller relatives will have a better chance at survival and will pass on their genes resulting in the evolution of smaller sized organisms.
In change to physical condition if it begins to cool down which organisms will be at advantage?
the larger endotherms because they are less likely to freeze to death. so there for as evolution continues the next generation will be seen to be larger.
Whats and example of physical change in the environment in relation to the peppered moth
Light, which can also give an effect. for example the peppered moth in Industrial England that had to cope with all the pollution with made it harder for the amount of light to camouflage the like coloured moths leaving the existence to the dark peppered moths
What is another impact of a physical change in the environment in correlation to schlerophyll plants?
Dryness, Organisms that can reduce water loss in a drying environment will have a better chance of survival . An example of this evolution is then as Australia drifted twenty million years ago more north and it became hotter and drier. The once present Beech forests had to give way to the dominant schlerophylls of the present.
Explain a chemical change in the environment in relation to oxygen.
Earth originally had an anoxic environment with no free oxygen until Obligate anaerobes began photosynthesising releasing their waste oxygen into the atmosphere. The free oxygen had a major impact on all sorts of chemicals produced on earth. this resulted in the slow extinction of obligate anareobes, and the raise in mutations better suited to the newly maintained environment
What do antibiotics show in response to a change in environment?
They show a change to a chemical environments which can lead to a change in the species, which once the many microbes would have been killed by an antibiotic to now having a 98% resistance.
Explain the example of ticks in changing chemical conditions.
The cattle tick was a major pest on cattle graziers in north Australia. these ticks induce “tick fever” the first attempt to control this included an arsenic based cattle dip, at first this reduced and killed ticks until by 1936 resistance was shown , DDT was then introduced, eradicated but then resistance was shown the next lot of chemicals was phosphate pesticides to which then resistance was also developed.
Explain the example of ticks in changing chemical conditions and how they managed resistance with evolution?
Resistance to each of the different pesticides involved different inherited variations of tick genes. Once the pesticides though were in large use it became a selecting agent for survival of the fittest, of which would breed and pass on the genes of resistance. this occurred in turn at the introduction of each new pesticide.
Failed attempts to control tick populations by use of chemical pesticides are a reminder that?
populations can show evolutionary changes over a few generations.
Another example of change in chemical environments is the brush tail possum explain.
in the southwestern corner of WA, several species of native plants produce fluoroacetate a poison known commercially as 1080. Populations of the brush tail possumn are found to also be living in regions of the toxin, their response to the poison was measured and it is seen they are resistant to the toxin, other possumns outside the range show that they have no resistance.
What did the presence of fluoroacetate in the diet of the in range possumns suggest?
that the toxic plants acted as a agent of selection so that over time the resistant possumns had higher survival and reproduction rates than the non resistant possumns
Resistance is an?
Inherited variation.
Describe the change in environment in relation to competition for resources.
The world has limited resources but unlimited biotic potential , individuals will always struggle with members of their own species for survival. For example the fastest cheetah is more likely to catch the reebok. Whilst the fastest reebok is more likely to avoid the cheetah. This is an example of the struggle for survival which has due to evolution resulted in both species becoming very fast.
Animals may compete for?
Food, water, shelter, mates etc….
In relation to the change in environment correlated with competition for resources, there can be events that remove competition. Name an event.
The age of the dinosaurs, few mammals were in existence Most niches in the environment were already occupied by organisms better suited to the environment therefore all mammalian organisms lived a Spartan life style. Though upon the extinction of the dinosaurs the competition was removed and the mammals were able to survive. Competition within their own species then evolved with the addition and favourable mutation. This lead to mammals beginning to survive easily as they became more and more suited to the environment.
Explain evolution.
Means a change in living things over time.
Microevolution explain.
Changes within a species over a relatively short period of time. Eg breeds, races and varieties.
Macro evolution explain.
When one species evolves to form another over millions of years.
Natural selection is the?
Mechanism for evolution.
What is the acronym VERAI?
Variation, Environment, Reproduction, Adaption, Isolation.
Variation in correlation to VERAI
Natural variation in every population
Environment in correlation to VERAI
Change of environment causes competition.
Reproduction in correlation to VERAI
Best adapted survive and reproduce. Passing on genes
Isolation in VERAI
For many macro evolutions groups or species must be isolated to prevent reproduction.
What are some areas of study supporting evolution?
Palaeontology, Biogeography, Comparative embryology, Comparative anatomy and biochemistry
