biodiversity and ecosystems Flashcards
what is biodiversity?
the variety of different species on earth or an ecosystem.
why is a rising population causing harm to the environment? (2)
the population needs more resources to survive.
demand for a higher standard of living. (more materials and energy)
how does human waste effect water land air?
water - sewage and toxic chemicals.
land - bury nuclear waste and landfill.
air - smoke and acidic gases.
how does carbon dioxide and methane trap sun energy?
gases in the atmosphere absorb radiation from the earth’s surface that would normally be radiated out.
the gases then reemit the radiation back to earth heating it up.
what are the negatives of global warming? (4)
rising sea levels.
plant and animal distribution changes.
changes in migration patterns.
reduced biodiversity.
what is deforestation?
cutting down forests. (for farming or crops)
what are 2 negatives of deforestation?
less carbon dioxide taken in. (reduced photosynthesis so more carbon in atmosphere)
less biodiversity. (forests are habitat for many species)
how does destroying peat bogs release CO₂
- plants in bogs don’t fully decay because there isn’t enough oxygen.
- these plants form peat.
- peat bogs are usually cleared for farming where the peat is cut and dried.
- now there is enough oxygen for microorganisms to decompose the peat.
- the organisms respire with oxygen and release carbon dioxide. (and when peat is burnt for fuel)
why is biodiversity sometime not maintained? (3)
costs money.
balancing biodiversity and food security.
development needs land.
what are trophic levels? (food chain)
different stages of a food chain. (numbered using their position in the food chain)
what are decomposers?
bacteria and fungi that decompose dead plant and animal material. (by releasing enzymes to break dead stuff into soluble molecules that can be absorbed)
what is a pyramid of biomass?
a pyramid made of bars that shows the mass of living material at each trophic level. (how much the organisms at each level weigh if you put them together)
why is biomass lost between each stage of the food chain? (3)
(only ~10% of biomass is transferred between trophic levels)
organisms don’t always each every part of another organism.
organisms don’t absorb all the food they eat
some biomass is converted into other substances lost as waste.
how do you calculate the efficiency of biomass transfer?
efficiency = biomass transferred to next level ÷ biomass available from previous level x 100
what is food security?
having enough food to feed a population.
what is biotechnology?
living things are manipulated to produce a useful product.
how is mycoprotein made? (for quorn)
- the fungus fusarium is grown in aerobic conditions on glucose syrup. (for food)
- the fungus is harvested and purified to produce mycoprotein.
how is bacteria engineered to produce insulin?
genetic engineering is transferring a gene between organisms.
1. a plasmid is removed from a bacteria.
2. the insulin gene is removed from a human. (with an enzyme)
3. the plasmid and gene are mixed.
4. ligase enzymes are added to produce recombinant DNA. (2 DNA stuck together)
5. the new DNA is put into a bacteria.
6. the new bacteria is grown in a lab.
what are mutations?
a random change in an organisms DNA. (change the sequence of bases)
what are insertion deletion substitution mutations?
insertion - a new base is inserted into the base sequence.
deletion - a random base is deleted from the base sequence.
substitutions - a random base is changes in the base sequence.
what is sexual reproduction? (in terms of gametes)
the fusion of male and female gametes.
what is asexual reproduction? (in terms of gametes)
no fusion of gametes. (no mixing of chromosomes, no genetic variation, offspring are genetically identical to the parent)
how does meiosis produce cells with 23 chromosomes?
- a cell duplicates its genetic information. (2 columns of chromosomes)
- chromosomes line up in the middle of the cell and are pulled apart to form 2 cells.
- chromosomes line up in the middle again and are pulled apart. (by the arms)
- you end up with 4 cells with 23 chromosomes.
what are the advantages of sexual and asexual reproduction?
sexual - variation in offspring can make them better suited for living in an environment.
asexual - only one parent, less energy, faster
what organisms can produce asexually and sexually?
malaria. (asexual in human, sexual in mosquito)
fungus.
plants.
what X Y configuration are males and females?
male - XY
female - XX
(Y causes male characteristics)
why do egg cells only ever have X chromosomes?
the female only has XX chromosomes.
what do genetic diagrams show?
the possible alleles of offspring.
what is the difference between genotype and phenotype?
genotype is the genetic information for characteristics.
phenotype is the actual physical appearance.
is cystic fibrosis and polydactyly recessive or dominant?
cystic fibrosis - recessive.
polydactyly - dominant.
