GCSE biology

Home

Get App

Create

define the term evolution

changes in the characteristic of species over time
when do scientists think life on earh began

3 billion years ago
how many species of living organisms exist today

30 million
how many species of living organisms are thought to have existed since life on earth began

3 billion
what has happened to most of the organisms that are though to have existed scince life on earth began

most of them have become extinct
scientists have collected a lot of evidence for evolution from

fossils
what are fossils

they are the remians or partial remians of organisms that lived in the past found preserved in rock or evidence of organisms having been there
what can fossils tell us
- the shape of an animal
- the size of an animal
- what age the animale lived in
- what the animal looked like in terms of structure and apperance
fill in the blanks to describe how fossils were formed
when an animal ..... , the .... parts of its .... .... leaving the .... parts such as ..... and .... . .... ... and ...... develop in the ..... . ..... work thier way into it and gradually replace it and fossils are formed
there are other kinds of fossils such as .... , which become .... by .... and .... into .....
in other cases a .... is produced when a .... .... becomes .... in .... . the organism .... leaving a ..... (or ....) which shows the .... of an organism
another method is where animals have become .... by a ..... ... which stops them .... e.g .... , ... and ....
- dies
- soft
- body
- decay
- hard
- bones
- teeth
- tiny holes
- spaces
- bone
- minerals
- ---------------
- footprints
- covered
- mud
- harden
- rock
- -----------
- mould
- dead organism
- buried
- mud
- decays
- space
- mould
- shape
- -------------
- covered
- natural preservative
- decaying
- amber
- ice
- tar
which part of the organism remains after the soft parts have decayed

bones and teeth
give 2 examples of a soft part of an animal
- tissue
- organ
explain how a mould is produced

a mould is produced when when a dead organism becomes buried in mud . the organism decays leaving a space (or mould) which shows the shape of the organism
give two examples of natural preservatives
- amber
- ice
what use is the information which is obtained from fossils

we can find out what the organisms looked like
fossils allow us to see the .... between .... ...... and ..... .....
- relationship
- present organisms
- past organisms
to our knowledge only a tiny fraction of the organisms which have died have become fossilised . suggest a possible reason for this
- lots of animals may just have been soft bodied
- many fossils are very deep in the earths crust and sea bed therefor we may have just not found them yet
suggest 2 possible reasons why animals may become extinct
- natural disasters
- food shortages
name a long extinct species
- dodo
name a more recently extinct species

golden toad
define species

a group of organisms that have many chracteristics in common and are able to breed together
fill in the table below with the main features of each of the subgroups of verterbrates
The question is this. In your reading of this tree, which group is the most closely related to fishes: frogs, lizards, birds, cats, or humans?

frogs

Author

Anonymous

143170

Card Set

GCSE biology

Description

revision

Updated

2012-03-22T18:20:14Z

Show Answers