Darwin And Wallace Flashcards
What is Darwin’s theory of evolution by natural selection
Darwin proposed that:
- individual organisms within a particular species show a wide range of variation for a characteristic
- individuals with characteristics most suited to the environment are more likely to survive and to breed successfully
- the characteristics that have enabled these individuals to survive are then passed on to the next generation
The theory is called natural selection
Who was Charles Darwin and what did he do
Charles Darwin was an English naturalist who studied variation in plants, animals and fossils during a five-year voyage around the world in the 19th century.
Darwin visited four continents on the ship HMS Beagle.
Darwin observed many organisms including finches, tortoises and mocking birds, during his five week visit to the
Galapágos Islands, near Ecuador in the Pacific Ocean.
He continued to work and develop his ideas once he returned from his voyages.
What beliefs did Darwin’s theory of evolution challenge
Darwin’s theory of evolution challenged the idea that God made all the animals and plants that live on Earth, which contradicted the commonly held Christian views of his era.
He did not publish his scientific work and ideas until 28 years after his voyage.
observations, which were backed by many years of experimentation; his discussions with like-minded scientists and his developing knowledge of geology and fossils; he proposed the theory of evolution by natural selection
.
Who was Alfred Wallace
- Alfred Russel Wallace was a great admirer of Darwin
- fellow naturalist
- independently proposed the theory of evolution by natural selection
Wallace worked around the world gathering evidence to support his evolutionary theory.
He is best known for studying warning colouration in animals, and examples include the Golden Birdwing Butterfly (Ornithoptera croesus).
proposed a theory of evolution, which matched Darwin’s unpublished ideas that he had kept secret for nearly 20 years. This encouraged Darwin to collect his scientific ideas and collaborate with Wallace. Wallace produced scientific journals with Darwin in 1858, which prompted Darwin to publish On the Origin of Species the following year.
.
Evidence for evolution - resistant bacteria
Explain antibiotic resistance
- Bacteria can evolve quickly
- they reproduce at a fast rate.
- Mutations of bacteria produce new strains.
- Some bacteria might become resistant to certain antibiotics, such as penicillin, and cannot be destroyed by the antibiotic.
- evolution of the bacteria is an example of natural selection and supports Darwin’stheory of evolution.
Development of resistance
What are the main steps of resistance (3)
The main steps in the development of resistance are:
- random mutation occur in the genes of individual bacterial cells
- some mutations protect the bacterial cell from the effects of the antibiotic
- bacteria without the mutation die or cannot reproduce when the antibiotic is present
What is MRSA
Why have number of strains increased
What should’ be done In order to reduce the rate of development of antibiotic resistant strains:(3)
MRSA is methicillin-resistant staphylococcus aureus, and it is very dangerous because it is resistant to most antibiotics.
The number of resistant strains has increased, partly due to the overuse and misuse of antibiotics. This has resulted in more infections that are difficult to control.
- doctors should not prescribe antibiotics inappropriately, such as for the treatment of non-serious infections
- patients should always complete the full course of antibiotics to ensure all bacteria are killed and none survive to mutate and form resistant strains
- the agricultural use of antibiotics should be restricted
What was 1st antibiotic - when produced
Why aren’t so many new antibiotics discovered / created now
What might lack of new antibiotics lead to
- Penicillin was the first antibiotic to be produced on a mass scale in the 1940s.
derived from the Penicillium fungus
-Many new types of antibiotics were discovered during the 1950s and 1960s, but more recently, this has slowed greatly.
- Recent concerns of increasing resistance have created the need for new antibiotics, but they are costly and very slow to develop.
- Some scientists fear that we are fighting a losing battle against resistant bacteria, which may ultimately lead to people dying from simple infections, for example following operations.
Evidence of evolution in fossils
What is a fossil
Examples of what formed from
A fossil is the preserved remains of a dead organism from millions of years ago. Fossils are found in rocks and can be formed from:
- hard body parts, such as bones and shells, which do not decay easily or are replaced by minerals as they decay
- parts of organisms that have not decayed because one or more of the conditions needed for decay are absent for example,
dead animals and plants can be preserved in amber (hardened tree resin), peat bogs,tar pits or in ice - preserved traces of organisms, such as footprints, burrows and rootlet traces - these become covered by layers of
sediment, which eventually become rock
Where are fossils mostly found
What is difference around older rocks and newer rocks
Why is studying fossils useful to scientists
Fossil remains have been found in rocks of all ages. Fossils of the simplest organisms are found in the oldest rocks, and fossils of more complex organisms in the newest rocks. This supports Darwin’s theory of evolution which states that simple life forms gradually evolved into more complex ones.
Evidence for early forms of life comes from fossils. By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth.
There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind. What traces there were may have been destroyed by geological activity. This is why scientists cannot be certain about how life began.
