Unit 20 - Human influences on ecosystems Flashcards
Impacts of agricultural machinery
- Reduces labor costs
- Reduces food prices
- More land mass can be used
- Greater quantities of food can be made more efficiently
Function of chemical fertilizers
Give nutrients for plants to grow
Impact of chemical fertilizers
- Increase crop yields
Impact of insecticides
- Kill insects
- Protect crops from damage - improve yield and quality
Impact of herbicides
- Reduces competition for resources between weeds and plants
Selective breeding
Humans selecting individual animals or plants with desirable features, crossing them to produce the next generation
Monoculture
Growing only one variety of crop in an area at a given time
Advantages of intensive farming
- Simplicity - tailored to one crop
- Higher yields - more efficient because crops grow optimally
- Reduced costs - Costs of production are lowered and then cost of produce as well
- Larger land and machinery - large areas of land can be used and hence machinery to increase efficiency
Disadvantages of intensive farming
- Land clearance - deforestation & destroying habitats of native species
- Reduced biodiversity - pathogens and pests spread more quickly, more substances like insecticides need to be used - not enough food for animals and damages the food web
- Soil damage - machinery can compact soil making it harder for plants to grow - land is vulnerable to erosion after nutrients are depleted
- Water pollution - water runoff can be contaminated and hurt organisms
- Air pollution - animal waste pollutes
Biodiversity
The diversity or variety of living organisms in a certain habitat or ecosystem
Habitat
A place where an organism lives
Human activities that lead to habitat destruction
- Increased use of land - Natural habitats are destroyed for crops ad farming due to more need for food with a higher population
- Extraction of natural resources - pollution from fuels burning, damaging habitats while searching for resources, facilities needed
- Water pollution - oil spills, untreated sewage, careless trash disposal, mining waste, nitrates from fertilizers, herbicides & pesticides, metal runoff
Deforestation
The cutting down of trees in forests
Impacts of deforestation
- Reduced biodiversity - many food webs collapse without trees
- Flooding - rain flows directly into rivers and lakes because no vegetation restricts water flow + soil washes away
- Loss of soil - protective vegetation is lost and soil can be eroded
- Species extinction - species migrating due to habitat destruction can go extinct and slow-growing plants can
- Increased carbon dioxide - less photosynthesis so the concentration of carbon dioxide in the atmosphere increases
Pollution
The release of any substance that has an undesired, unexpected, harmful or toxic effect on the environment
Untreated sewage - source and effects
- Source - human and animal waste released without passing through sewage treatment plants
- Effects - Can contain harmful pathogens that cause disease, oxygen used by decomposers when rotting, hormones can affect organisms, eutrophication
Fertilizers - source & effects
- Source - runoff from farmland
- Effects - Algal bloom and eutrophication
Eutrophication
A process in which additional nitrate and other ions in water lead to the death of aquatic organisms
Occurrences in eutrophication
- Increased nitrate concentration in water
- algae grows to algal bloom that blocks sunlight from the surface of the water
- Aquatic plants can’t carry out photosynthesis
- Plants die and are decomposed by decomposers that carry out aerobic respiration
- Fish and other organisms die because oxygen is used up by decomposers
Non-biodegradable plastics
Plastics that cannot be digested by bacteria
Impacts of non-biodegradable plastics
- Long-term exposure to air, water & light can make toxic compounds
- When broken down, greenhouse gases release
- Toxins can leach in soil and pollute water sources
- Animals eating plastic
- Burning leads to emissions
- Animals can be entangled
The Greenhouse effect
A natural process that maintains the temperature range on earth
Two main greenhouse gases
Carbon dioxide & methane
Sustainable resource
Something that is produced as rapidly as it is removed from the environment
Non-renewable resources
Resources that are being used up faster than they are being formed
Methods of conserving forests
- Setting quotas for logging which can lead to banning
- Using education programs
- Creating protected areas
Solutions to overfishing
- Education
- Closed seasons
- Protected areas
- Quotas
- Controlled net types and mesh size
- Monitoring
Threats to wildlife
- Climate change - sudden changes which species might not be able to adapt to
- Hunting - killing specific animals
- Introduced species - can disrupt the balance of the ecosystem
- Over-harvesting - can lead to extinction
Types of conservation programs
- Monitoring and protecting - routes, behavior, feeding, mating and habitat changed can be recorded
- Education - educating people and raising awareness and understanding
- Seed banks - storing samples of seeds from many plant species
- Captive breeding - can increase number of individuals in a population - often done in zoos or sanctuaries
Artificial insemination / AI
- Obtaining sperm from a desired male
- Semen is harvested and transported to a breeding female
- Semen is artificially inserted into the female’s reproductive tract
In vitro fertilization / IVF
- Sperm from the male and eggs from the female are both extracted
- Fertilization is carried out under controlled conditions in a Petri dish
- Once the egg has divided into an embryo, it is inserted into the reproductive tract of a female
Reasons for conservation
- Reducing extinction of species
- Increasing biodiversity
- Protecting vulnerable ecosystems
- Maintaining important ecosystem functions
