Chapter 48 - Humans as a planetary force

Question 1

Anthropocene epoch

Answer 1

Era where humans have the biggest impact on the planet

• as opposed to glaciers, etc.

Question 2

How do humans impact the environment

Answer 2

of people influences:
- energy and land use
- individual and societal choices

Question 3

What countries have the highest and lowest energy use

Answer 3

Americans, Canadians, Europeans, and Australians live energy-intensive lives.

Populations in rural Africa and parts of Asia consume relatively little energy per person.

Question 4

Ecological footprint patterns

Answer 4

Living standard up (more developed countries) = ecological footprint up

takes 8 hectares for one American

Question 5

Ecological footprint

Answer 5

All the energy, food, materials, and services we use and how much land is required to provide those resources

Question 6

CO2 source

Answer 6

Primarily from combustion of fossil fuels

see: presence of C13 down compared to C12 (fossil fuels)

Started during mid 1800s industrial revolution

Question 7

Compared to volcanoes

Answer 7

In past: volcanoes = huge impact

Annually, we add about 100 times more CO2 to the atmosphere from fossil fuel than produced by all Earth’s volcanoes together.

No counteracting process removes CO2 at comparable rates.

Question 8

How do humans contribute CO2

Answer 8

• burning fossil fuels
• clearing land for agriculture = burning biomass

Question 9

Global temperature changes

Answer 9

Annual temp. up

North warms more than south bc
- more CO2 released in northern hemi + doesn’t move down
- more land mass up north, land heats more than H2O

Question 10

Greenhouse effect

Answer 10

Solar radiation energy absorbed by earths surface, some is radiated back again, that is absorbed by the greenhouse gases in the atmosphere, which direct half of the heat energy back towards earth like GREENHOUSE GLASS PANES where it can’t escape

• necessary to a certain point, but as CO2 increases, so does greenhouse

Question 11

How are methane levels rising

Answer 11

Most of the methane delivered each year to the atmosphere is generated by methane-producing archaea, which thrive in the guts of cattle and the waterlogged paddies where rice is cultivated.

The thawing of permafrost at high latitudes releases additional methane that was trapped in frozen soils when the ice formed long ago.

Question 12

Future of global warming

Answer 12

As atmospheric CO2 levels will reach twice their pre-industrial levels later this century, mean global temperature will rise by 2.6°C to 4.1°C

Why hot up north:
- snow lasts less
- exposed soil
- heats a lot

Amazon:
- forests removed through slash and burn agriculture
- crops only last 6 years
- exposed soil heats local + co2 released heats global

Question 13

Consequences of climate change

Answer 13

• More extreme weather (ex. droughts, floods, etc)
• Populations that can adapt to environmental shifts will persist, while those that cannot will be challenged.
• Some locations will benefit. For example, temperature increase in New England and Scandinavia will mean longer growing seasons.
• Many places will become drier. For example, farmers in southeastern Australia have experienced the worst droughts in a century.

Question 14

Plant response to environmental change

Answer 14

• Many species flower a week earlier than they did in the nineteenth century
• If unable to change their flowering time, may result in species declining
• May grow leaves, flowers, or fruit earlier
• hummingbirds arrive at spring breeding grounds earlier too due to their mutualistic relationship

Question 15

What do species do when global warmed (altitude)

Answer 15

Shift towards higher elevations where temp. would be like the temp. of their original place of distribution

Question 16

Populations response to climate change

Answer 16

• may not have time for natural solution
• migration, change distribution (ex. expansion), or extinction

Question 17

Assisted migration

Answer 17

The deliberate transplantation of populations to new good places

very expensive! (hedgehogs)

Question 18

Plant sensitivity index

Answer 18

Plants in higher altitudes are more sensitive to warming
- this is also due to changes in water availability

= diminished population size, decreased growth rates, and even extinction

Question 19

The “Deadly Trio of CO2” impact on oceans

Answer 19

1. An increase in ocean temperature.
2. A decrease in the pH of seawater (acidification).
3. A decrease in capacity of warm seawater to store oxygen (deoxygenation).

Question 20

Effects of CO2 (1. increase in ocean temp.)

Answer 20

• many marine pops are operating near their upper limit of thermal tolerance
• affects primary producers = less phytoplankton = less fish
• bleaching in coral reefs = algae quit their hosts

Question 21

Effects of CO2 (2. pH = more acidic)

Answer 21

About one-fourth of the CO2 produced by humans during the past century has been absorbed by the ocean.

• CO2 also dissolves in seawater to form carbonic acid.
• Increasing the abundance of CO2 in the oceans causes the pH of seawater to decrease, a phenomenon known as ocean acidification.

= animals + algae cant precipitate CaCO3 for their skeletons + erosion of corals

Question 22

What to do about rising CO2

Answer 22

• renewable energy
• wind
• the sun
• tidal energy
• nuclear power
• reforestation
• individual choices; energy-efficient transportation and appliances

Question 23

Benefits of using natural resources

Answer 23

1. reducing CO2 emissions pr kilowatt of energy
2. allows us to conserve finite natural resources
3. helping contain cost of energy production

Question 24

Impact on the nitrogen cycle

Answer 24

industrial reactions to make ammonia + fertilizers + other things add 240 mill tons of fixed nitrogen / per year

nitrate fertilizers runoff into waters
- denitrifying bacteria use some of the added nitrate for respiration, returning N2 to the atmosphere—and also generating N2O, yet another potent greenhouse gas

Question 25

Eutrophication

Answer 25

excessive nutrients due to runoff in water = more plant life + animal death due to lack of O2

Question 26

Impact on the phosphate availability

Answer 26

• used as fertilizer
• becomes runoff
• In the Everglades, phosphate-loving cattails and other introduced plants are expanding at the expense of native plants.

gonna run out of phosphate
- only source is mining
- running out of mine sources
= mine poorer resources = more expensive and unsustainable

Question 27

Feeding a growing pop.

Answer 27

meat consumption up
corn for biofuel up

Solns:
Devote more lant to crops
- forests and natural grasslands get plowed
= decreasing the biological storage of carbon + threatening biodiversity

Increase the yield of current fields
- takes more fertil.
- takes fossil fuels to power farm machinery
= climate change + eutrophication

Question 28

How to increase crop yield

Answer 28

• breeding
• genetic mod.
• pest reduction
• reducing food spoilage (ex. in stores, at home, during transport)

= still fertilizing issues

Question 29

The theory of island biogeography

Answer 29

As the size of a habitable area decreases, species diversity within the habitat will decline

We see it…
conversion of natural ecosystems to cropland
+ expansion of cities and towns
= less area for natural habitats

Question 30

Deforestation and Tropical Habitat Loss

Answer 30

Habitat loss in tropical rainforests poses one of the most important threats to biological diversity.

• deforest through clear cutting for grazing / croplands

Deforestation over the next century could eliminate 40% to 50% of all tree species in the Amazon rainforest; as the forest disappears, so will untold numbers of insect, mite, and other animal species.

• losing 0.25% of species annually (5000-25000 species)

Question 31

Pollution effects

Answer 31

• neonicotinoids kill bees and birds
• plastics kill marine life
• air poll kills 4 mill humans / year

Question 32

Threats to biodiversity - overexploitation

Answer 32

Overexploitation
- by hunting, fishing, and logging
ex. cod in Newfoundland were abundant until overfishing
ex. By 2003, nearly 30% of open ocean fisheries had declined by 90% or more.
Reports from 2019 indicate that about 17% of all global fisheries have collapsed and the annual catch in another 30% is unsustainable.

Question 33

Threats to biodiversity - Invasive species

Answer 33

Introduction of nonnative species into new communities

Invasive species can affect native species because invasive species have no natural predators, tend to be r-strategists, and are strong competitors.

ex. Kudzu plants (from Japan to US to retard soil erosion)
Zebra mussel from europe to great lakes (accidentally)
Brown tree snakes rom australia/asia to Guam (reduce native reptile diversity)

Question 34

Disease

can mutate as they go between species

Answer 34

• drug resistant malaria (resistant to insecticides + drugs)
• In any given year, malaria infects an estimated 250 million people, causing half a million or more deaths.
• In parts of Africa, the direct and indirect effects of malaria account for almost half of all childhood mortality.
• Insecticide-soaked bed nets have reduced transmission by as much as 90%. However, mosquito strains have begun to emerge that are resistant to DDT and another family of insecticides called pyrethroids.
• drug resistant tuberculosis
  Tuberculosis, a lung infection spread by inhalation of the bacterium Mycobacterium tuberculosis
• 1.5 mill deaths / year esp in Africa
• need strict drug regimen for 6 mos
• if incomplete = antibiotic resistance

Question 35

Amphibians indicate environmental changes

Answer 35

“Canaries in the gold mine”

• One-third of all amphibian species are threatened with extinction.
• Exchanging gases through their skin, makes amphibians especially sensitive to environmental disruption.

Question 36

Why amphibian decline

Answer 36

Habitat destruction, pesticides, and fungal infections have all contributed to amphibian declines.

Question 37

Conservation biology

Answer 37

Addresses the challenge of sustaining biodiversity in a changing world crowded with people

Question 38

Biodiversity hotspots

Answer 38

2 dozen exist, high priority for conservation efforts

relatively small areas that have unusually high numbers of indigenous species that are under threat from human activities, on land

contain at least 1500 endemic plant species and have lost 70% of their original habitat area

Question 39

Endemic species

Answer 39

Species found in one place and nowhere else

Question 40

Ecosystem services

Answer 40

1. Biodiversity provides cleaner air and water.
2. Biodiversity provides greater primary productivity and improved resilience to environmental disruption.
3. Biodiversity provides untapped sources of food and molecular compounds for use in medicine and agriculture.

Question 41

Biological reserves

Answer 41

• should consider corridors
• will protect other species in the reserve

Question 42

Sustainable Development

Answer 42

The rate at which we use resources should be no higher than the rate at which that they can be replenished.
- ex. logging

It can be difficult to quantify sustainable yields for agriculture.
- it includes many costs
- depends on weather (droughts/floods)

Question 43

Problems with loosing biodiversity

Answer 43

• Lost species mean lost opportunities for the discovery of novel compounds for medical research.
• Diminished biodiversity may make communities less productive and less resilient to fires, hurricanes, or other environmental events.
• Need for food for the world.

Question 44

Future jobs will need to consider the environment

Answer 44

Doctors/public health;
Engineers; energy efficient machines / slowing spoilage
Teachers; Teach kids to meet challenges and be responsible citizens
Biologists; Perhaps most important, biologists will work with economists, lawmakers, and others to ensure that government policies reflect what we know about the natural world on which we all depend. (+many specific things for each type of biologist)