5.1 Evidence for evolution Flashcards
What does evolution describe?
Change over time
What encodes heritable characteristics?
Genes
What is the definition of biological evolution?
A change in the allele frequency of a populations gene pool over successive generations
How are heritable characteristics transferred between generations as?
Alleles
When talking about the evolutionary change in living organisms what is it referring to?
Heritable characteristics
How do fossil records provide evidence for evolution?
By revealing the features of an ancestor for comparison against living descendants
What is a fossil?
A fossil is the preserved remains or traces of any organism from the remote past
What do preserved remains provide?
They provide a direct evidence of ancestral forms
What do preserved remains include?
Bones
Teeth
Shells
Leaves etc
What do traces provide?
They provide indirect evidence of ancestral forms
What do traces include?
Footprints
Toothmarks
Burrows
Faeces
What is a fossil record?
The totality of fossils - both discovered and undiscovered
What does the fossil record show?
The fossil record shows that over time, changes have occurred in the features of living organisms
How can fossils be dated?
Fossils can be dated by determining the age of the rock layer in which the fossil is found
What is strata?
Rock layers
What does each strata represent?
Each strata represents a variable length of time that is classified according to a geological time scale
How do sedimentary rock layers develop and what does that mean?
Sedimentary rock develops in a chronological order meaning that the lower layers are older and the new strata form on top
What indicates a sequence of of development in the law of fossil succession?
That different kinds of organisms are found in rocks of particular ages in a consistent order
Describe where prokaryotes appear in the fossil record?
Prokaryotes appear in the fossil record before eukaryotes
Describe where fern appear in the fossil record?
Ferns appear in the fossil records before flowering plants
Describe where invertebrates appear in the fossil record?
Invertebrates appear in the fossil record before vertebrate species.
What is the law of fossil succession?
The chronological sequence of complexity by which characteristics appear to develop
What does the law of fossil succession suggest?
It suggests that newer species likely evolved as a result of changes to ancestral species.
Why do very few organisms become fossils?
Because fossilisation requires an unusual set of specific circumstances in order to occur