L. 29 - The Human Footprint

Question 1

LO

Answer 1

1. Review how human activities affect the ecology of natural systems
2. Understand the impacts of pollution and how it affects the ecology of natural systems
3. Understand how pollutants move into natural systems
4. Understand the ecological impacts of habitat fragmentation
5. Understand the ecological impacts of climate change
6. Appreciate the science behind this ecological knowledge and understanding

Question 2

Toxic inputs

Answer 2

• Pesticides
• Manufactoring
• Industrial accidents
• Atmospheric pollution
• Chemical spills
• Plastics
• Nanoparticles

Question 3

Contaminants

Answer 3

Contamination is the presence of a substance where it should not be or at concentrations above ground
- Should’nt be there or should be at lower concentration

Question 4

Pollutants

Answer 4

Pollution is concentration that results in adverse biological effects to resident communities

Question 5

Bioaccumulation

Answer 5

Occurs when an organism absorbs a toxic substance at a rate greater than it can be broken down/ destroyed
- Accumulates in the body faster than it can be broken down

Particularly in higher predators at the top of the food webs

Question 6

Biomagnification

Answer 6

• Bioaccumulation leads to biomagnification

Occurs when there is an increase in concentration of the substance in tissues at higher trophic levels
- When predators get sick it will impact the whole ecosystem as there won’t be any top-down pressure on lower trophic levels

Question 7

How pollutants travel into new environments
- Inuit people consuming PCB example

Answer 7

• There was no agricultural/ manufactoring in North Canada
• Bioaccumulation of PCB in narwhals from eating contaminated fish
• The inuit people would consume almost every part of the narwhal, leading to biomagnification and bioaccumulation of PCB.

Question 8

How pollutants may spread

Answer 8

• Migration of snimals that are experiencing bioaccumulation or biomagnification
• Chemicals get into atmosphere in warm climates and travel, when a cool temperature is reached where the chemicals will fractionate out of atmosphere into water, then into animals
• Breakdowns of pollutants is usually slower in colder regions than warm/ tropical climates

Question 9

Habitat Fragmentation

Answer 9

• One of the major contributors to biodiversity loss
• Fragment size and isolation are primary factors of diversity
• Shape matters alot as edge of fragment has a large impact
• Connectivity and corridors enhance landscapes

Question 10

2 Classic effects of fragmentation

Answer 10

1. Biomass collapse
2. Irriversible shifts (ecological meltdowns)

Question 11

Biomass collapse

Answer 11

Amazonial rainforest example:
- In the fragmented plots, the closer to the edge had a lower biomass compares to those closer to the centre
- The edge effect

Question 12

The Edge Effect

Answer 12

The microclimate factors strongly impact the edge by:
- wind
- Hydrology
- Light

More light access allows more diverse plants to grow, such as woody wines which do NOT account for a loss of trees

Question 13

Ecological Meltdown

Answer 13

• Habitat fragmentation and loss of large animals
• Leads to ecosystem breakdowns due to no top-down regulation
• Often leaving many/ only herbivors, eating all the plants leading to trophic cascades, further creating an ecological meltdown

Question 14

Changes expected and now Observed

Answer 14

Animals and Plants:
- Range shifts
- Abundance changes
- Change length in growing season
- Earlier flowering, insect emergence, migration and egg laying
- Morphology shifts

Hydrology and Glaciers:
- Glacier shrinkage
- Permafrost thawing
- later freeze and earlier breakup of river/ lake ice