5. Evolution and Biodiversity Flashcards
What does the fossil record provide?
Provides evidence for evolution by revealing the features of an ancestor for comparison
What are heritable characteristics?
The characteristics that an organism processes due to its genetic makeup.
Evolution
The heritable characteristics of a species change over time
Dating
Allows the chronological ordering of organisms
Radioisotopes
Help date more accurately of the fossils
What is selective breeding?
A form of selection and another bit of evidence for evolution. It is man-made.
What is the role of humans in selective breeding?
Role: to choose which organisms breed and which does not
Explain the selective breeding of domesticated animals. Give examples to support your answer.
Most dog breeds today are artificial. Their original breeding is from wolves, they are tamed and bred for docile traits. This shows that evolution has occurred as they can differ a lot from wild ancestors.
What are 4 examples of selective breeding?
- Breeding race horses for speed
- Breeding egg-laying hens to lay lots of eggs
- Breeding cattle for increased meat or milk production
- Breeding dogs for herding, hunting or simply for specific physical features
What are homologous structures?
Same structure but not same functions.
It means that something came from the same ancestry or origin.
What is a pentadactyl limb?
A limb with five digits, characteristic of tetrapods vertebrates. It evolved from the paired fins of primitive fish as an adaptation to locomotion on land and is not found in modern fish.
What is a divergent evolution?
An accumulation of differences that led to the formation of new species
What does divergent evolution explain?
Explains the similarities in limb structure even if each of them has different methods to locomotion
What is an analogous structure?
Same function but not same structure. Eg. Butterfly and bat wings. It shows that they did not have a common ancestry
What is a convergent evolution?
Structures develop to resemble each other and same function but not of same origin.
What is speciation?
Process by which new species form
How do species form?
Physical separation of populations:
- due to landslides, changes in rivercourse
- the population remain isolated for a long time and they change, become genetically different.
What is adaptive radiation?
A process in which organisms diverge from orginal species to new species that allows them to adapt to their new environment
What is continuous variation?
Continuous variation is the idea of gradual divergence where organisms go through slow variation process to form new species
What is the role of industries in industrial melanism?
- Burn fossil fuels due to power machinery
- Produces large amounts of sulfur dioxide
- Produces vast quantities of soot that changed the color of tree barks
- light organisms can survive more in the light tree areas and dark in dark tree areas.
- this led to the decrease in light organisms in polluted areas and more dark organisms
What is variation?
The difference in physical features of organisms, this is a good measure for a healthy gene pool because it shows a range of alleles present in a species and this accounts for the variation in the population in the population.
List the three causes of variation with details.
- Mutations: any change to the DNA sequence, from a change in a single base or the whole segment of the chromosome
- Meiosis: produces gametes with alleles and increases genetic variation of the species
- Sexual reproduction : combination of the genes results in a zygote
What is an asexual reproduction?
producing a clone that is identical to itself
What is the only way a variation could be present in asexual species ?
mutations
What is natural selection?
Organisms that are better adapted to their environment tend to survive and produce more offspring.
How does the gene pool change overtime?
Number of offspring adapting to the environment increases, increasing the frequency and characteristics that help them adapt, and thus the gene pool changes overtime