B2.6 Old and new species Flashcards
What can we use to find out when organisms existed?
We can date rocks. Fossils are found in rocks.
Name a hard part of an animal which will not decay easily.
Bones, teeth, shells, claws
why are some fossils destroyed over time?
because of geological activity such as earthquakes
Why is it difficult to find traces of early life forms?
Early life forms had soft bodies so few traces were left behind.
Define Extinction
Extinction is where a species which once existed completely died out.
Give three examples of why extinction might take place.
- New diseases may be introduced
- Natural changes
- a new predator may be introduced to an area
- Natural disasters
How can a new predator cause extinction of a species?
It may kill all of a species, or eat all of that species food source.
Define ‘Predator’.
An animal that preys on other animals for food
what is geographical isolation?
When two populations become physically isolated by a geographical feature.
Give an example of Geographical isolation.
- Mountain ranges and old craters
- a new river separates two areas
define Speciation.
Formation of a new species
How can we tell when speciation has occurred?
The two populations can no longer successfully interbreed.
