B18 - Biodiversity and Ecosystems Flashcards
What is biodiversity
The variety of all the different species on earth or in an ecosystem
Advantages of a high biodiversity
- Makes an ecosystem stable + more resilient to environmental changes
- Ecosystem is less dependant on only one species
- This could be for food or shelter
- If the population of a species falls, it won’t affect the whole ecosystem
Reasons for deforestation
- To grow rice fields or for cattle grazing
- The grow crops to be used to make biofuels
Ways deforestation impacts the environment
- Burning trees releas CO2
- Decomposing trees release CO2
- Lack of trees reduces absorbtion of CO2
- Loss of biodiversity
What has the population increase lead to?
- Increased use of Earth’s resources
- More waste products
How is water pollution caused and its effects
- Sewage contain huamn excretemnt is released into rivers or streams
- Fertilisers from farms
- Toxic chemicals from factories
- This kills aquatic organisms - reduing biodiversity
How is air pollution caused and what are its effects
- Burning fossils fuels can cause acid rain
- Also releases large particulates which are pollutants
- This kills animals and plants and reduces biodiversity
- Also causes global dimming and health issues
- Carbon dioxide - global warming, changing migration, extreme weather, loss of habitat
How is land pollution caused and what are its effects
- Waste dumped in landfills - reduces habitats
- Toxic chemicals e.g. heavy metals pollute soil killing organisms
Steps in eutrophication
- Nitrates get in water
- Leads to algal bloom
- PLants beneath die from lack of light
- Algae then die
- Bacteria decompose algae and use up oxygen
- Fish and organisms die
What is bioaccumulation
- Chemicals get into the food chain
- Chemical remain in animals tissues
- Over time, chemical levels will increase as they take in more
What is biomagnification
- The concentration of chemicals increases in tissues of organisms as you move along a food chain
- Affects top predators the most
How do humans reduce land available for organisms
- Infrastructure
- Farming
- Quarries
- Landfill
What is peat and what are its advantages
- Dead plant material that hasn’t decayed due to acidic conditions in bogs
- They trap CO2
- Provide a habitat for lots of unique organisms
What is peat used for and disadvantages of this
- Used for cheap compost
- Burned to produce electricity or for heat
- This reduces biodiversity
- Peat decays once extracted releases CO2
- Burning peat also releases CO2
Biological consequences of global warming
- Loss of habitats
- Bleaching of sea corals
- Animals extend range to originally cooler areas
- Migration patterns changing
- Crops can’t be grown in too hot conditions
How can biodiversity be maintained
- Breeding programs for endangered species, avoiding inbreeding
- Protection and regenration of rare habitats (coral reefs, mangroves)
- Growing hedgerows or field margins
- Reducing deforestation
- Reducing CO2 emissions
- Recycling resources - less in landfills
What are apex predators
- Carnivores with no predators
- This means they are at the top of the food chain or at the highest trophic level
What is biomass and how do you calcuate it
- The dry mass of material in a living organism
- Therefore, the organism has to be killed and dried
- Wet biomass is inaccurate as moisture of organisms varies
What is the 1% and 10% rule
- 1% of light hitting the ground is absorbed by plants fro photosynthesis
- 10% of the original biomass is passed onto the next trophic level
How does the 10% rule affect the number of organisms at each trophic level
- Food chains aren’t lonnger than 5 levels as there isn’t enough energy transferred
- As you go up, the number of individuals decreases
Why isn’t all biomass transfered between each trophic level
- Glucose (biomass) is used in respiration to make energy
- Not all parts of an organism are injested
- Not all injested material is absorbed, some just gets egested
- Some is used in maintaining body temp.
- Some is lost as waste products from reactions e.g. urea
how to calculate the efficiency of biomass transfer
efficiency = gain in biomass/total biomass intake
Biological factors which are threatening food security (6)
- Increasing birth rate
- Changing diets in developed countries
- New pests and pathogens
- Environmental change due to climate change
- Cost of agricultural resources
- Conflicts
Advantages and diasdvantages of factory farming
Advantages - more efficient, gives animals optimum nutrients needed, eggs can be easily harvested
Disadvantages - spread of pathogens, antibiotic reistant bacteria, animals get stressed, ethical issues
