In this article, we are going to look at some useful notes which have come up over the years regarding the study of evolution topic in your junior cycle biology course.
Biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance. The central ideas of evolution are that life has changed over time and that different species share common ancestors.
"You can't even begin to understand biology, you can't understand life, unless you understand what it's all there for, how it arose - and that means evolution."
Evolution - Junior Cycle Science Learning Objectives
The aim of studying evolution at this level is to ensure that at the end of this course students will be able to identify the following information:
- Define what is meant by the terms 'evolution' and 'species'
- To be able to compare and contrast small scale and large scale evolution.
- Explain how evidence for evolution is obtained
- Have an understanding of Darwin's contribution to the understanding of evolution - "theory of natural selection"
- Define how new species are formed
- Define house pieces become extinct
- Give a brief description of Wallace's contribution towards the understanding of evolution
We won't be able to look at everything all heading above in detail, but we will manage to look at a few and hopefully provide you with some new study material that you may not already have.
Junior Cycle Science – Evolution, Charles Darwin
Who was Charles Darwin?
Darwin was the English naturalist who was responsible for the scientific theory of evolution by natural selection. In 1859 Darwin published "the origin of species", his book on the theory of evolution. During his research, Darwin travelled to the Galapagos Islands where he studied different species, he had a fondness for finches in particular but also studied many different types of insects and plants including sea slugs.
Why where were Darwin's studies so important to our understanding of evolution?
In essence, Charles Darwin's theory of natural selection provides us with the following material to aid us with our study of Evolution:
- The more offspring, the better the chance of surviving - that producing more offspring increases the probability of a species surviving, therefore, decreasing their chances of going extinct.
- More competition - the more offspring produced means the more they have to compete with each other for basic needs such as food, habitats and mating rights.
- Constant population - despite species having several offspring in order to increase the probability of surviving due to the competition being high only the best-adapted organisms in a species survive.
- The adoption of organisms - the majority of Darwin studies focused on variations. These were adaptions made in each generation of the species and passed on to their offspring to ensure they could survive things such as antibodies, size, agility and capabilities.
“It is not the strongest of the species that survives, not the most intelligent that survives. It is the one that is the most adaptable to change.”
Junior Cycle Science – Evolution, Alfred Wallace
Alfred Wallace was also an English naturalist whose studies and theories heavily influence our understanding and current studies of evolution.
Wallace spent many years travelling the world is collecting and researching species, used for years in the Amazon basin writing and collecting information on its inhabitants. Much like Darwin, he collected butterflies insects and birds in his search for clues to solve the mystery of the Origin of the Species.
The first one of what do you might say are two of Wallace's important articles was published in 1855 it was dealing with the origin of new species. Wallace then proposed that new species arise by the progression and continued divergence of varieties that outlive the parent species in the struggle for existence.
In early 1858 he sent a paper outlining these ideas to Darwin, who saw such a striking coincidence to his own theory that he consulted his closest colleagues. The men decided to present two extracts of Darwin’s previous writings, along with Wallace’s paper, to the Linnean Society. The resulting set of papers, with both Darwin’s and Wallace’s names, was published as a single article in the Proceedings of the Linnean Society in 1858.
"In my solitude I have pondered much on the incomprehensible subjects of space, eternity, life and death."
Key Terms Relating to Evolution - Junior Cycle Science
While studying the topic of evolution just like other topics which you will study in junior cycle science, such as the digestive system and human reproduction, there are certain terms that you really should make a note of. Just some of those terms include:
- Evidence – what is meant by evidence and evolution is the study of fossils or palaeontology. Fossils include things such as bones teeth pollen grains and even footprints that have been preserved. By using a process called carbon dating Fossils can be aged giving a timescale to a particular species.
- Extinction – simply put this means that a particular species no longer exists. Some of the leading causes of extinction include environmental changes and increased competition with other species. (some environmental changes are down to humans commercializing wildlife habitats and their impact on climate change)
- Adaption – An adaptation is a feature that is common in a population because it provides some improved function, such as changes in size, agility and capabilities. Adaptations are well fitted to their function and are produced by natural selection.
- Small scale evolution – this involves changes over a few generations but there are no new species formed. (changes in gene frequency in a population from one generation to the next)
- Large scale evolution – this is the changes that occur over many, many generations and eventually, a new species will develop. (changes in gene frequency in a population from one generation to the next)
- Species - a species is a group of organisms with similar characteristics capable of interbreeding.
- New species/speciation – new species form by speciation, which is the evolutionary process that occurs when a group within a species separates from other members of its species and develops its own unique characteristics. Basically, Speciation is how a new kind of plant or animal species is created.
For more information on Evolution for Junior Cycle, check out the notes provided in these google slides.
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