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Biology Unit 5.1 The evidence for evolution, Biology Unit 5.2 - Coggle…
Biology Unit 5.1
The evidence for evolution
Fossil record
Transitional Fossils
Display common characteristics between ancestral groups and show evidence for macroevolution
Heritable characteristics
The characteristics that an organism possesses due to its genetic make-up and will pass to its offspring
Macroevolution and its evidence
Large-scale evolutionary changes that take place over long periods of time which leads to the development of a new species
The fossil records showing transitional fossils
Why is the fossil record incomplete?
Only hard parts of an organism such as bone or shell will be preserved and usually only fragments of that remain
Trace fossils
A type of fossil that is an imprint from organisms without hard parts and provide evidence for the activities of organisms
Selective breeding
Artificial selection : the human practice of selecting animals or plants that have certain desired traits and are then bread in attempt to keep those desired traits throughout generations
Natural selection
A process in which certain individuals have variation of traits which can benefit the species by helping them reach reproductive age and pass on their genes
A breed
A group of animals within a species that have similar characteristics
Microevolution and its evidence
Microevolution happens on a smaller scale within a species. It is the evolutionary change of the allele frequencies within a population
The change in the variety of dog breeds
How does selective breeding show evidence for evolution?
Changes within a species can be observed due to genetic selection
Comparative anatomy
Homologous (evolution)
Have a similar structure, position and evolutionary origin but different functions
Pentadactyl limb
A limb with 5 digits found in amphibians, reptiles, mammals and birds
Divergent evolution
When two species have the same structure but use it in different ways due to their environment
Adaptive radiation
The process in which organisms rapidly diverge from the form of their original species into several new specialised forms another form in order to make use of their environmental niche.
This leads to divergent evolutions and the creation of a new species
Analogous
Have the same function but different ancestral origin
Convergent evolution
Organisms that are not closely related who have similar structures used for the same purpose.
Habitats or diets may be similar
Continuous variation and species divergence
Discontinuous variation
A type of variation that is influenced by only one or a few genes, can be categorized and is not influenced by the environment
Continuous variation
A type of variation that is influenced by many genes, has a wide range of variability and is easily influenced by environmental factors
Speciation
The formation of a new distinct species in the course of evolution
Biology Unit 5.2