Back to AI Flashcard MakerBiology /LGS A-Level OCR Biology - Unit 4 - Variation and Evolution Part 1
Give 4 sources of evidence for evolution
Palaeontology (fossils)
comparative anatomy
comparative biochemistry
comparative embryology
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Key Terms
Term
Definition
Give 4 sources of evidence for evolution
Palaeontology (fossils)
comparative anatomy
comparative biochemistry
comparative embryology
How can the relative age of fossils be determined?
Over time sediment is deposited to form rock strata
recent rock strata are found at the top and older rock strata are found at the bottom
radioisotope...
How do fossils provide evidence for evolution?
Fossils of the simplest organisms are found in the oldest rocks
fossils of more complex organisms are found in more recent rocks
allow relationships b...
What is comparative anatomy?
The study of similarities and differences between organisms’ anatomy
How does comparative anatomy provide evidence for evolution?
-Homologous structures provide evidence for divergent evolution and that from a common ancestor different species have evolved
What are homologous structures?
A structure which appears superficially different (and may perform different functions) in different organisms but has the same underlying structure
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| Term | Definition |
|---|---|
Give 4 sources of evidence for evolution | Palaeontology (fossils)
comparative anatomy
comparative biochemistry
comparative embryology |
How can the relative age of fossils be determined? | Over time sediment is deposited to form rock strata
recent rock strata are found at the top and older rock strata are found at the bottom
radioisotope dating can be completed on fossils to date rock strata |
How do fossils provide evidence for evolution? | Fossils of the simplest organisms are found in the oldest rocks
fossils of more complex organisms are found in more recent rocks
allow relationships between extinct and living organisms to be investigated
sequence in which organisms are found matches ecological links |
What is comparative anatomy? | The study of similarities and differences between organisms’ anatomy |
How does comparative anatomy provide evidence for evolution? | -Homologous structures provide evidence for divergent evolution and that from a common ancestor different species have evolved |
What are homologous structures? | A structure which appears superficially different (and may perform different functions) in different organisms but has the same underlying structure |
What is divergent evolution? | Species diverge over time into two different species, resulting in new species becoming less like the old one |
What is comparative biochemistry? | Similarities and differences between the chemical make up of organisms |
How does comparative biochemistry provide evidence for evolution? | Molecules change over time
some important molecules are highly conserved among species
slight changes that do occur in these molecules can help identify evolutionary links |
How does comparative embryology provide evidence for evolution? | Embryos of different animals looks very similar
shows animals develop in a similar way
implies the process of embryonic development has a common origin |
What is variation? | Differences in characteristics or genes within or between species |
Define intraspecific variation | Differences between individuals within the same species |
Define interspecific variation | Differences between different species |
What are the 2 causes of variation? | Environment and genetics |
Are environmental effects heritable? | No |
Give 2 examples of environmental effects | Hair dye
Diet |
Are genetic factors heritable? | Yes |
What are the 5 causes of genetic variation? | Presence of a different allele
random fertilisation/random fusion of gametes
random mating
meiosis
mutations |
What are the two types of mutations? | Point mutations and chromosomal mutations |
What are point mutations? | Change in the base sequence of DNA |