B15-Genetics and Evolution Flashcards
What did Mendel study in his experiments?
Mendel studied the inheritance patterns of pea plants, focusing on characteristics like smooth vs. wrinkled peas and green vs. yellow peas.
Mendel discovered that characteristics were inherited in clear and predictable patterns and that some traits were dominant over others. Mendel kept detailed records and used mathematical models to analyse his results, which was uncommon at the time.
What is monohybrid inheritance?
Monohybrid inheritance refers to the inheritance pattern of a single trait, as studied by Mendel in his pea plant experiments.
What was Lamarck’s theory of evolution?
Lamarck’s theory suggested that organisms adapted to their environment and evolved through the inheritance of acquired characteristics. Lamarck believed that if an organism used a feature frequently, it would grow and develop, and if not used, it would shrink and be lost.
How did Lamarck explain the long neck of giraffes?
Lamarck explained that giraffes’ necks grew longer over generations as they stretched to reach higher leaves, and these acquired traits were passed to offspring.
What was a major problem with Lamarck’s theory?
A major problem was the lack of evidence for the inheritance of acquired characteristics, such as big muscles not being passed on to children.
What did Darwin observe on the Galapagos Islands?
Darwin observed a variety of species that varied from island to island, with strong similarities and adaptations to local conditions. Darwin found strong similarities between types of finches on the different islands. Yet each was different and adapted to make the most of local conditions.
Darwin’s main ideas:
The individual organisms in a particular species tend to show a wide range of variation for each characteristic.
Reproduction always gives more offspring than the environment can support. The organisms that have inherited the characteristics most
suited to their environment - the ‘fittest’- are more likely to survive and breed successfully.
When they breed, they pass on the characteristics that have enabled
them to survive to the next generation.
What is Darwin’s theory of evolution?
Darwin’s theory is that all living organisms have evolved from simpler life forms through natural selection
What did Darwin not know about when he proposed his theory?
Darwin did not know about genes; he observed that useful inherited characteristics were passed on.
Why was Darwin’s theory of natural selection challenging to accept?
It challenged the religious belief that God made all animals and plants, and despite Darwin’s efforts other scientists still believed that there was initially insufficient evidence and no known mechanism for inheritance.
What was a major reason for the slow acceptance of Darwin’s theory?
The mechanism of inheritance (genes and genetics) was not known until 50 years after Darwin published his ideas.
What was Wallace’s idea about species adaptation?
Wallace believed that poorly adapted forms of a species would die out, leaving only the better-adapted forms to survive and breed (Natural selection)
What is natural selection?
Natural selection is the process by which alleles that help organisms survive and breed successfully are selected in a population.
How can part of a population become isolated?
Part of a population can become isolated due to new environmental conditions.
What happens to alleles in an isolated population?
Alleles for characteristics that enable organisms to survive and breed successfully in the new conditions are selected, which may differ from those in the original environment
What is speciation?
Speciation is the process where characteristics of an isolated population change so much that they can no longer interbreed with the original population to produce fertile offspring, forming a new species.
What leads to the formation of a new species?
The selection of different alleles in isolated populations leads to changes in characteristics, eventually resulting in the inability to interbreed with the original population, forming a new species.
What is geographical isolation?
Geographical isolation occurs when two populations become physically separated by a geographical feature, such as a mountain range, river, or island.
What is environmental isolation?
Environmental isolation happens when the climate changes in one area but not in others, affecting the breeding times of plants and animals and leading to new species.
What are fossils?
Fossils are the remains of organisms from millions of years ago preserved in rocks, ice, and other places.
How can fossils be formed?
Fossils can be formed when an organism does not decay due to lack of oxygen, poisonous gases, or low temperatures. They can also form when harder parts of an organism are replaced by minerals over time.
What can fossils tell us?
Fossils can provide insights into the appearance, diet, and even the DNA of ancient organisms.
What is the most widely accepted theory for the extinction of dinosaurs?
A giant asteroid collided with Earth around 65 million years ago, causing massive environmental changes.
What evidence supports the asteroid impact theory?
A layer of crater debris found worldwide and the presence of iridium, a mineral formed by massive impacts.
What are the causes of extinction?
changes to the environment and climate over geological time and single catastrophic events,
such as massive volcanic eruptions or collisions with asteroids.
How do antibiotic-resistant bacteria develop?
Resistant bacteria survive antibiotic treatment, reproduce, and increase in population, leading to the spread of resistant strains.
Why is overuse of antibiotics a problem?
Overuse of antibiotics can lead to the development of resistant strains of bacteria, making bacterial diseases harder to treat.
What measures can prevent the development of resistant bacteria?
Measures include not overusing antibiotics, completing prescribed courses of antibiotics, and restricting agricultural use of antibiotics.
Why should patients finish their course of antibiotics?
Finishing the course ensures all bacteria are killed, preventing the survival and mutation of resistant strains.
What is MRSA?
MRSA (methicillin-resistant Staphylococcus aureus) is a bacterium resistant to many antibiotics, commonly found in hospitals.
How can the spread of MRSA be reduced in hospitals?
Measures include hand hygiene, using specific antibiotics, maintaining high hygiene standards, isolating infected patients, and ensuring visitors wash their hands.
Why is it difficult to develop new antibiotics?
It is challenging to find chemicals that kill bacteria without damaging human cells, and the development process is expensive and slow.
How do bacteria evolve resistance to antibiotics?
Bacteria evolve rapidly due to fast reproduction rates. Mutations can produce resistant strains that survive and reproduce through natural selection.
What are the consequences of antibiotic-resistant bacteria spreading?
Resistant strains spread because people are not immune to them, and there is no effective treatment, leading to increased mortality.
What is classification in biology?
Classification is the organisation of living things into groups based on their similarities to make studying them easier.
What are the main groups in Linnaeus’s classification system?
The main groups are kingdom, phylum, class, order, family, genus, and species.
Who is Carl Linnaeus?
Carl Linnaeus was an 18th-century Swedish botanist who developed the natural classification system based on the structure and characteristics of organisms.
Why is classification important?
Classification helps us understand the relationships between different groups of living things, recognise biodiversity, and provides a common language for scientists.
What are the six kingdoms in the current classification system?
The six kingdoms are archaebacteria, eubacteria, protista, fungi, plants, and animals.
What is the three-domain system?
The three-domain system is a classification level above kingdoms, proposed by Carl Woese, dividing life into Archaea, Bacteria, and Eukaryota.
What evidence supports the three-domain system?
The evidence comes from detailed analysis of cell ribosomes’ biochemistry and reproduction methods.
What are the three domains and their kingdoms?
Archaea: Contains one kingdom, archeobacteria, including extremophiles.
Bacteria: Contains one kingdom, eubacteria, including true bacteria and cyanobacteria.
Eukaryota: Contains four kingdoms – protista, fungi, plants, and animals.
How do scientists build evolutionary trees?
Scientists use similarities and differences between organisms, including DNA analysis and fossil data, to build evolutionary trees.
What role does DNA analysis play in classification?
DNA analysis helps determine species relationships by identifying similarities and differences in genetic material
What does the evolutionary tree suggest about pandas and red pandas?
They had a common ancestor long ago, but the wrist thumb evolved separately to solve different ecological problems.
How do scientists combine data to create evolutionary trees?
Scientists combine traditional observation, DNA analysis, and fossil evidence to create accurate evolutionary trees.
