B6 - life on Earth - Past, Present, and Future Flashcards
What is the process natural selection (3)
- advantageous genetic variant/allele
- more likely to survive and reproduce
- and pass on genetic variant
this process may continues over many generations, leading to all of them having the advantageous genetic variant.
What is evolution?
it’s the change of inherited characteristics of a population over several generations, through the process of natural selection
What is speciation?
the formation of 2 or more species from the original species
What is a fossil?
Any trace of an animal or plant that lived long ago. Most commonly found in rocks
how can we observe fossils as evidence for evolution?
By arranging fossils in chronological order, gradual changes in organisms can be observed. This provides evidence, as it shows how species have changed and developed over many years.
how can bacteria show evolution?
- develops random mutations in DNA, which introduces new variants in population, changing phenotype.
e.g a bacterium could become less affected by an antibiotic. (survives) - this leads to the resistant variant being passed on to offspring and becoming more common overtime
(natural selection)
What is selective breeding?
Is mating the best organisms to get good offspring.
what is the process of selective breeding? (3)
the parent organisms with the best characteristic are selected
they breed
the best of the offspring are selected and bred
process is repeated over several generations
Problems with selective breeding
- reduces gene pool due to inbreeding
- inbreeding can cause health problems as there is more chance of developing harmful genetic disorders
- badly affected if a disease arrives
What is classification?
the process of organising organisms into groups based on their characteristics and evolutionary relationships
How do scientists use DNA analysis
scientists can use DNA sequencing to compare particular genes or entire genomes using samples of tissue.
they look for similarities
the more similar the DNA sequences between species, the more closely related they are and are more likely to classified in the same group
How can scientists use DNA sequencing to estimate speciation? (2)
scientists can estimate how frequently how mutations happen.
by finding the number of different genetic variants between 2 species, scientists can estimate speciation
what is biodiversity a combination of? (3)
- diversity of living organisms in a particular area
- diversity of different genes and alleles in a particular area
- diversity of different ecosystems in a particular area
human interactions can reduce biodiversity (3)
1) increasing human population
2) industrialisation; more raw materials, more waste products
3) globalisation
why human interactions can destroy ecosystems and biodiversity (2)
1) habitat destruction can reduce the amount of land and resources available to other animals and plants
2) waste/pollution; toxic chemicals from industry can pollute oceans, affecting plants/animals that rely upon them
What does sustainability mean?
meeting the needs of today’s population without harming the environment or using up resources, so that future generations can still meet their own needs.
protecting specific species (2)
- protected in their natural habitat e.g by banning the hunting of some species
- breeding programs in captivity to increase the number of species before releasing into the wild
protecting habitats and ecosytems
1) setting aside specific protected areas helps conserve entire ecosystems by restricting the development of land
Economic issues of maintaining biodiversity
- expensive to conserve species or habitats
- selling natural resources may help boost the country’s economy, but a negative effect on the country’s ecosystems
moral issues of maintaining biodiversity
- the conversation of some endangered species may have no obvious benefit for humans
- morally wrong from to stop developing countries use raw materials that could boost economy
