Study "variation , evolution + genetic engineering", a flashcard deck on FORKSAI.
Define 'variation' as it relates to individuals within a species.
Variation is defined as the differences observed between individuals belonging to the same species. These differences can arise from either environmental or genetic factors.
Explain how sexual reproduction contributes to genetic variation within a species.
Sexual reproduction causes variation because offspring receive one set of genetic information from each parent. This process, particularly through meiosis, shuffles the genes, resulting in a unique combination of genes in the offspring that differs from either parent.
What is a mutation, and what are the two main types of mutations mentioned?
A mutation is a change in the structure or amount of DNA in an organism. The two main types of mutations are gene mutations and chromosome mutations.
Describe a gene mutation and provide an example of a human condition caused by it.
A gene mutation occurs when genes, which code for proteins, are damaged or copied incorrectly, leading to the production of a new protein that may not function properly. Examples include Cystic fibrosis and Haemophilia.
Explain what a chromosome mutation is and give a human example.
A chromosome mutation involves a change in an individual chromosome's structure or a change in the total number of chromosomes. Down syndrome, caused by an extra chromosome 21, is an example of a chromosome mutation in humans.
Identify two distinct sources or causes of mutations.
Mutations can be caused by spontaneous changes resulting from mistakes in DNA replication, or by mutagens. Mutagens are agents such as ionizing radiation (e.g., UV rays, X-rays) and certain chemicals (e.g., tobacco smoke, formaldehyde) that alter DNA in a cell.
Define 'evolution' according to the provided notes.
Evolution is defined as the changes between members of a species and the emergence of new species from older species over time. These changes occur in response to environmental shifts, primarily driven by natural selection.
What is 'natural selection' and how does it relate to genetic traits?
Natural selection is the mechanism by which members of a species possessing genetic traits that enhance their survival in a specific environment are more likely to reproduce. Consequently, they pass these advantageous traits on to the next generation, leading to the prevalence of these traits over time.
State Darwin's (and Wallace's) first two observations that led to the theory of natural selection.
Darwin's and Wallace's first two observations were that organisms overbreed and that population numbers tend to remain constant. These observations led them to conclude that there must be a struggle for existence among organisms.
How did Darwin's third observation, regarding inherited variations, contribute to the concept of 'survival of the fittest'?
Darwin's third observation noted that inherited variations occur in populations. This led him to conclude that organisms possessing traits necessary for survival would reproduce and pass these traits on, a concept encapsulated by 'survival of the fittest' or natural selection.