Evolution- Paper 2 Flashcards
What are fossils?
Remains of organisms from millions of years ago that are found preserved (in rocks, ice etc.)
What are criterias for decay to occur?
Oxygen, bacteria (decomposers), correct temperature
Describe the five steps of fossilisation by mineralisation.
- Organism dies and falls to the ground; 2. Flesh decays, leaving the skeleton behind; 3. Bones are covered in sand/soil; 4. Bones become mineralised and turns into rock (fossil); 5. Rock with fossil emerges due to geological movement (eg. earthquake) and erosion occurs to reveal fossil
What are the three different types of fossils that can be formed?
Mineralised skeleton; Undecayed due to trapped in ice or amber; Preserved traces of organisms (eg. footprints, leaves)
Give 4 reasons why the fossil record is incomplete.
- Many earliest life forms are soft-bodied; 2. Most organsisms did not become fossilised; 3. Most early fossils were destroyed by geological activity; 4. Many fossils are not yet found
How is the fossil record helpful?
It shows how much organisms have changed and developed over time, and can show the environment and climate then
Define ‘extinction’.
Permanent loss of all members of a species
State three causes of extinction.
New predators; New diseases/pathogens; New/sucessful competitors
What causes mass extinction? Suggest two examples of this cause.
Single catastrophic event that also affects climate over a long period (eg. asteroid collision, volcanic eruption)
Suggest a chain of events initated by an asteroid collision that could lead to the extinction of dinosaurs.
Asteroid impact causes huge fires and earthquakes –> volcanic eruptions –> dust/ash cloud covers atmosphere –> less sunlight reaches the Earth surface –> temp drop massively + plants die –> loss of food source led to other animals’ extinction
What is antibiotic resistance?
Bacteria becoming resistant means it cannot be killed by a certain antibiotic
What causes antibiotic resistance?
Random mutations in bacteria/Bacteria sharing resistant genes
Describe the steps in which a bacteria strain develops resistance to an antibiotic.
- Mutation occurs in an individual bacterium within a population; 2. It survives and reproduces rapidly, making more bacteria with its resistant gene; 3. Overtime, all bacteria within the population have that gene
Why can bacteria evolve quicker than other organisms?
Because bacteria can reproduce at a quick rate
Suggest 3 methods to prevent and slow down the development of antibiotic-resistant strains.
- Do not overuse antibiotics; 2. Patients finish antibiotic course every time; 3. Restrict agricultural use of antibiotics
Why must patients finish their course of antibiotics every time?
To ensure all bacteria are killed by the antibiotic, so none can survive to mutate and develop resistantce
Suggest 3 ways in which a hospital can reduce the spread of antibiotic-resistant strains.
Only use antibiotics if really needed; Use strain-specific antibiotics; Maintain high hygiene standards (eg. wash hands between patient visits); Isolate patients infected with resistant strain; Visitors wash hands as they enter and leave
Why is it difficult to develop new antibiotics to combat the appearance of new antibiotic-resistant strains of bacteria?
The development of new antibiotics is expensive and slow (won’t be able to keep up)
What does classification of organisms mean?
Organisation of living things into groups based on their similarities
Name the person who developed the classification system.
Carl Linnaeus
State the 7 heirarchical levels of the Linnaean classification system.
Kingdom, phylum, class, order, family, genus, species
Every organism has a scientific name using a binomial system. What does binomial mean?
Two names
Which language does the binomial naming system use?
Latin
The binomial name of an organism is made up of two words. What does each word represent of that organism?
The first word is the genus; second word is the species
