(Module 14) Genetics And Evolution Flashcards
What is the definition of fossils
Fossils are the remains of organisms from millions of years ago which are found in rocks
What is the definition of Extinction
Extinction occurs when there are no remaining individuals of a species still alive, they all die out
How can new predators cause extinction
New predators can wipe out unsuspecting prey if the prey has no adaptations to avoid them. Predators may evolve or migrate to a different location. Sometime this is because of human intervention e.g hedgehogs were brought to Scottish islands to kill off slugs, but they bred rapidly and ate the egged of rare sea birds
How can new diseases cause extinction
New diseases are especially effective on islands where the animals population is close together (or plants). Can be very quick
E.g The Australian Tasmanian devil is already rare, but are being wiped out by a new form of communicable cancer the attacks and kills quickly
How can successful competition cause extinction
If an organism mutates or migrates to a new location, it can give itself an advantage over another. This can be done naturally, or by mistake by human intervention. A new successful competitor can take over an older species and wipe it out
E.g rabbits were brought to Australia, but they eat so much and bred so quickly that other native Australian animals are dying out as the rabbits eat all the food
How can environmental changes cause extinction
Changes in the climate can cause extinction if species cannot adapt quick enough to drastically different temperatures and conditions
What evidence is there that the giant asteroid wiped out the dinosaurs
There is a 180km in diameter crater in Mexico
There is a layer of rock formed around the world which would of been spread by dust. The further from the crater you go, the thinner the layer gets
Deep below the crater is iridium a mineral only formed when rock is hit with massive force (such as an asteroid strike)
What evidence is there that low light levels and temperatures would have followed a huge asteroid strike
When an asteroid hits the earth, huge masses of dust is thrown up. This dust hovers in the atmosphere, and remains there for some time, which blocks huge amounts of sunlight, causing low light levels and low temperatures.
What evidence is there that the changed climate after the giant asteroid wiped out the dinosaurs
Low light causes lower temperatures which stop plants growing and most would did out as sunlight is a source of food. Then, the herbivores would die out because because all the plants would be gone. The predators would die next because all the food they eat would be gone
What is the definition of a species
A group of similar organisms that are capable of interbreeding to produce fertile offspring
What is the definition of speciation
This is the formation of a new species due to evolution. May cause extinction of another separate species e.g early hominids
How are fossils formed
- Organisms are covered in sediment/sink in mud
- The soft parts decay/are eaten
- The bones/hard parts do not decay, most likely because one factor needed for decay is absent (e.g no oxygen)
- Minerals enter the bones, preserving them
- Layers of sediment get compressed over time forming sedimentary rock
How can bacteria become antibiotic resistant
Bacteria reproduces rapidly, so it evolves rapidly as well. If a bacteria cell mutates, then soon multiple cells with that mutation will soon be around. If this mutation makes the bacteria antibiotic, then it will survive, reproduce and damage the body. It would be incurable and unstoppable
How can antibiotic resistant bacteria be reduced
Doctors should not prescribe antibiotics irresponsibly, such as treating non-serious or viral infections
Patients should complete their course of antibiotics, and then stop using them
Give an example of an antibiotic resistant bacteria type
MRSA
