Genetics And Variation Flashcards
Continuous variation is…
…variation with no limit for the population (eg. Height)
How would you plot continuous variation data?
With a line graph
Discontinuous variation is….
…variation with distinct groups (eg. Eye colour)
How is discontinuous variation data plotted?
With a bar chart
What is a fossil?
The remains or impression of a prehistoric plant or animal embedded in a rock and preserved in petrified form
What are the three types of fossil formation?
Impression fossils
Preserved organisms
Mineral replacement
What is amber?
The historic remains of tree resin
Why are there more fossils of sea creatures than land creatures?
The water in the sea covers up a fossil quicker as the current washes the sediment over the fossil. The sediment is also less acidic and cooler in the sea than on land.
What is extinction?
When no individuals of a species remain
Name the 5 causes of extinction
Environment changes quickly A new predator A new disease Competition with a new species for food A catastrophic event
What is the first stage of fossil formation?
An animal dies, its skeleton settles on the sea floor and is buried by sediment.
What is the second stage of fossil formation?
The sediment surrounding the skeleton thickens and begins to turn to stone.
What is the third stage of fossil formation?
The skeleton dissolves and a mould is formed.
What is the fourth stage of fossil formation?
Minerals crystallise inside the mould and a cast is formed.
What is the final stage of fossil formation?
The fossil is exposed on the Earth’s surface
