Theory of Evolution Flashcards
What is the Theory of Evolution by Natural Selection?
Due to biodiversity, there will always be organisms in a population possessing traits that are better suited to a particular environment. These organisms are more likely to survive and reproduce to pass on their characteristics to their offspring. Conversely, those who possess un-favourable traits will not reproduce, nor survive.
What are the 4 steps involved in the Theory of Natural Selection?
- Variability: all populations have random differences or variation among their members.
- Heritability: variation may be inherited.
- Over-reproduction: organisms produce more offspring than the environment can support (i.e not all offspring survive).
- Competition - between organisms and the survival of the fittest.
- Speciation - the formation of a new species.
What are the 2 types of speciation?
Allopatric when populations become geographically isolated
Sympatric when the distribution of closely related species overlaps.
What are the 3 levels of biodiversity?
Genetic diversity - total number of genetic characteristics in the genetic make-up of a species.
Species diversity- measure of the diversity of different species in an ecological community
Ecosystem diversity - variation of different ecosystems, found in a region.
When did Darwin go on his scientific expedition?
In 1931.
Why did Darwin go on the scientific expedition?
He was a naturalist so it was his job to observe and collect specimens.
Why were Darwin’s observations significant?
His observations led him to his theory of evolution by natural selection.
Summarise how Darwin proposed the Theory of Evolution by Natural Selection from the finches.
Darwin observed variations in beak shapes and sizes among finch populations on different islands. He noted that these variations were well-suited to the specific environments and available food sources on each island. From this, Darwin inferred that the finches had descended from a common ancestor and that natural selection played a key role in their evolution.
Define speciation.
Speciation refers to the evolution of new species from an ancestral species as a result of reproductive isolation of populations.
What defines a species?
The ability to interbreed defines species. Interrupting breeding and the exchange of alleles through isolation can lead to the evolution of new species
Distinguish between macroevolution and microevolution.
Macro: Takes place over long periods of time (millions of years). Results in new species and sometimes families and orders.
Micro: Takes place over short periods of time. Results in changes within populations to produce varieties (not necessarily new species).
Involves changes in alleles, populations or species over short periods of time.
Driven by mutation, migration, genetic drift, natural selection.
Accumulation of microevolutionary changes can lead to speciation.
What is divergent evolution?
The pattern of evolution in which an ancestral species gives rise to two or more distinct species.
What is convergent evolution?
A pattern of evolution in which under similar selection pressures, two unrelated species evolve similar adaptations independently.
What is punctuated equilibrium?
- Established by Steven Jay Gould and Niles Eldredge.
- A theory in evolutionary biology that proposes that after a period of rapid evolution following a speciation event, a species becomes stable for a long period of time.
