Week 30

Question 1

Name two impacts of humans in the Anthropocene

Answer 1

Impact 1: Urbanization causes fragmentation, isolating populations and reducing genetic diversity within habitat patches

Impact 2: Human activities like hunting, farming, and habitat destruction contribute to the spread of zoonotic diseases and the extinction of larger, slow-reproducing organisms.

Question 2

Define the term zoonotic disease and explain its importance

Answer 2

A zoonotic disease is an infectious disease caused by pathogens (such as viruses or bacteria) that jump from animals to humans. These diseases are important because they can lead to pandemics (e.g., HIV, COVID-19) and pose significant threats to global health.

Question 3

Name at least 3 zoonotic diseases

Answer 3

HIV, H5N1, Covid 19

Question 4

Explain how habitat destruction, hunting, farming, and other intensive human disturbances have increased the number of zoonotic diseases

Answer 4

Habitat destruction forces wildlife into closer contact with humans, increasing transmission opportunities.

Hunting and wildlife farming (e.g., bushmeat, live markets) expose humans to animal pathogens.

Intensive farming and urbanization create stressful, unhygienic conditions that facilitate pathogen mutation and spread.

Question 5

Describe which types of organisms are threathened by human impacts, and which types of organisms typically beneift

Answer 5

Threatened: Large species, specialists (e.g., koalas), and those requiring large habitats (e.g., bobcats).

Benefit: Generalists (e.g., raccoons, white-footed mice) and species adaptable to urban environments (e.g., cliff swallows with rounded wings).

Question 6

What’s the difference between genetic diversity WITHIN patches and ACROSS patches?

Answer 6

Within patches: Genetic variety in a single isolated population

Example: White-footed mice in one urban park have low diversity due to inbreeding

Across patches: Differences between separate populations

Example: Bobcats in different forest fragments develop unique immune genes

Question 7

Summairze some of the impacts of our own actions on ourselevs, as humans in these ecosytems

Answer 7

Human activities (e.g., wildlife markets, deforestation) increase zoonotic disease risks (e.g., COVID-19, HIV).

Urbanization and pollution alter ecosystems, leading to pest adaptations (e.g., DDT-resistant bed bugs).

Loss of biodiversity threatens ecosystem services and increases human vulnerability to environmental changes.

Question 8

Background extinction rate

Answer 8

The number of species that would be expected to
go extinct over a period of time based on nonhuman factors.

Question 9

Zoonoses

Answer 9

A phenomenon where infections caused by bcateria, viruses or other parasites, are passed on from animals to humans. Most often, the animals are not affected by the pathogen and are merely acting as a host

Question 10

What do human disturbances reduce

Answer 10

They reduce the buffering effect of natural ecosystems

Question 11

What are the 3 main factors increasing disease spread in ecological epidemiology?

Answer 11

High host density (cities, farms, zoos)

Habitat destruction (forces animals together + human contact)

Artificial animal mixing (travel, wildlife markets, zoos)

Question 12

What is ideal for transmission & mutation

Answer 12

Wildlife markets

Question 13

Evolution vs adaptation vs adapting

Answer 13

• Evolution = change in frequencies of genes in a
  population over time
• Can be positive, negative, or neutral for the
  population.
• Adaptation = a trait that is heritable, benefits an
  organism and increases reproductive success in a
  particular environment.
• Positive by definition, occurring as a result of evolution
• Adapting = a general term for an organism or
  population changing in response to their
  environment.
• Positive, but not necessarily heritable.

Question 14

Name the five ways urbanization can affect evolution

Answer 14

1. Mutation – changes to DNA
2. Loss of genetic diversity within patches
3. More isolation of populations across
   patches → greater differences between
   patches.
4. Shift in the types of species that are
   favoured by natural (human) selection.
5. Adaptation!

Question 15

Urban pollution and mutation

Answer 15

Urban pollution can elevate mutation rates in birds and mammals

Question 16

Loss of genetic diversity

Answer 16

• Urbanization causes fragmentation: breaking up habitat into smaller pieces.
• Smaller patches = smaller populations
• Patches become isolated, little dispersal between
  patches.
• Genetic variation within patches drops.

Question 17

Why are live wildlife markets so likely to produce new diseases?

. Pathogens mutate in response to the close
presence of unknown species, because they
represent a new infection opportunity.
B. As pathogens spread within a species, they have
more opportunity to mutate.
C. Pathogens spread easily among species because of
the close quarters and stressed immune systems.
D. Both A and B
E. Both B and C

Answer 17

E. Both B and C

Question 18

What can urbanization cause?

Answer 18

decreased dispersal of organisms

Question 19

Which organisms are expericnng the highest rates of extinction

Answer 19

Large organisms that are slow to reproduce

Question 20

Background extinction rate

Answer 20

Number of species that would be expected to go extinct over a period of time based on non human factors

Question 21

Name the species most at risk for extinction

Answer 21

• Those that are large, and/or have require large
  territories of habitat.
• Those that are specialized to a very specific resource or
  a very specific natural habitat.
• Those that are naturally rare to begin with (have always
  had small populations)
• Those that are sensitive to changes in the environment
  or climate.

Question 22

Generalists vs specialists

Answer 22

• Generalists: a species that is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources
• Example: generalists have a varied diet.
• Specialists: can only thrive in a narrow range of environmental conditions, or has a limited ability to use resources

Question 23

Towards which species do human activites strongly shift selection towards ?

Answer 23

Generalists and smaller species

• Remove top predators such as wolves and big cats.
• Favours species that have a broad range of habitat
  and resource use.

Question 24

Bobcats and adapatation

Answer 24

• Bobcats in Thousand Oaks had been exposed to rat poison,
  which weakened their immune systems.
• Mange then killed so many bobcats, the annual survival rate
  dropped from 80% to 20%!
• The remaining bobcats had different MHC and TLDR genes,
  which help the immune system recognize disease.

Question 25

How does habitat destruction increase disease risk?

Answer 25

Packs animals into smaller areas → higher density Forces wildlife near humans → more spillover chances Stress weakens immunity → easier infections

Question 26

Give 2 examples of "artificial animal mixing" causing outbreaks.

Answer 26

COVID-19: Wildlife market (bats + pangolins + humans) Bird flu: Crowded poultry farms

Question 27

Define "spillover event" with an example.

Answer 27

When a pathogen jumps from animals to humans. Example: HIV (chimps → humans via bushmeat hunting).

Question 28

How do humans increase mutation rates in organisms?

Answer 28

Urban pollution causes DNA damage Example: Herring gulls near factories show more mutations Example: Lab mice exposed to chemicals develop more genetic errors

Question 29

How do humans reduce genetic diversity WITHIN patches?

Answer 29

Habitat fragmentation creates small, isolated populations Leads to inbreeding and genetic drift Example: Urban mice populations lose rare alleles over time

Question 30

How do humans increase genetic differences ACROSS patches?

Answer 30

Prevents gene flow between isolated populations Each patch adapts differently to local conditions Example: Bobcat populations develop distinct traits in separate forest fragments

Question 31

What kinds of adaptations do human activities drive in organisms?

Answer 31

Immune resistance (urban bobcats fighting new diseases) Dietary flexibility (mice evolving to neutralize aflatoxins in human food waste) Behavioral changes (birds adapting to city noise)

Question 32

Define: Genetic drift, Gene flow, Adaptive evolution

Answer 32

Genetic drift: Random changes in gene frequencies (common in small populations) Gene flow: Movement of genes between populations (blocked by fragmentation) Adaptive evolution: Beneficial traits becoming more common