Unit 2

Question 1

What is the relationship between primary productivity and biodiversity?

Answer 1

If primary productivity is high, biodiversity is also high.

Question 2

What are the 3 different levels of biodiversity? How are each of these levels affected by environmental stressors?

Answer 2

Genetic Diversity, Species Diversity, and Habitat Diversity

• The more genetically diverse a population is, the better it can respond to environmental stressors
• Loss of habitat leads to a loss of specialist species, followed by a loss of generalist species
• Ecosystems with a large number of species are more likely to recover from disruptions

Question 3

How do you quantify biodiversity?

Answer 3

Species Richness - The number of species in a given habitat

Species Evenness - The relative abundance of species in a given habitat

Question 4

What is a population bottleneck?

Answer 4

A population bottleneck is an event that drastically reduces the size of a population. This can cause inbreeding, susceptibility to diseases, and birth defects. The more important takeaway, however, is that population bottlenecks result in decreased genetic variation within a species.

Question 5

How does the loss of habitat affect biodiversity?

Answer 5

Habitat loss more greatly affects specialist species than generalist species, which is why we find that so many of these species are endangered. Specialist species tend to rely on a singular food resource for survival, so without that resource, their population tends to decline.

Question 6

What is natural selection, and how does it affect biodiversity?

Answer 6

Natural selection is the mechanism that drives evolution. It’s the idea that the organisms best adapted to their environment survive and reproduce, while less suited species are discontinued. This impacts biodiversity in the sense that external stressors might cause natural selection to decrease the diversity of organisms in a given environment (ex. Climate change and sea level rise will benefit organisms that thrive underwater, and harm those that thrive in low tide areas. Natural selection will cause these low tide organisms to die out, thus decreasing the species variation in that habitat.).

Question 7

What are some factors that might increase genetic biodiversity?

Answer 7

• Low variation in environmental stress
• Evolution, Mutation, Speciation
• Minor disturbances like surface fires, wind storms, and floods
• High habitat diversity

Question 8

What are some factors that might decrease genetic biodiversity?

Answer 8

• Continuous environmental stress
• Extinction
• Extreme disturbances, crown fires, clear cutting, and hurricanes
• Geographic isolation
• Invasive species

Question 9

What does anthropogenic mean?

Answer 9

Human influenced / Influenced by humans

Question 10

What are the 12 ecosystem services?

Answer 10

• Water, Land, Soil, Air
• Policy, Climate, Pollution, Land-use
• Strong Economy, Well-being, Food, Water, and Resources, Public Health

Question 11

What are the benefits of biodiversity?

Answer 11

Provisional Services, Regulating Services, Cultural Services, Supporting Services

Question 12

What are provisional services?

Answer 12

Provisional services are any type of benefit to people that can be extracted from nature (food, raw materials, freshwater, and medicinal purposes).

Question 13

What are regulating services?

Answer 13

Regulating services are processes that work to make ecosystems clean, sustainable, functional, and resilient to change (local climate and air quality, carbon sequestration and storage, moderation of extreme events, waste-water treatment, erosion prevention and soil fertility, pollination, biological control, water flow).

Question 14

What are cultural services?

Answer 14

Cultural services are non-material benefits that contribute to the development and cultural advancement of people (recreation and mental and physical health, ecotourism, aesthetic appreciation and inspiration for culture, art, and design, spiritual experience and sense of place).

Question 15

What are supporting services?

Answer 15

Supporting services are ecosystems themselves that couldn’t be sustained without the consistency of underlying natural processes (habitats for species and maintenance of genetic diversity).

Question 16

List some anthropogenic activities and their affects on biodiversity.

Answer 16

• Burning fossil fuels: Acid deposition = pH of water and climate disruption
• Deforestation: Loss of species and habitat
• Industrial Agriculture: Monocropping
• Overfishing: Loss of species
• Pesticide use: Loss of species
• Genetically modified crops: Loss of genetic variation
• Water pollution: Loss of water habitat diversity

Question 17

What is the effect of habitat fragmentation?

Answer 17

Habitat fragmentation instigates natural selection to produce decreased biodiversity, particularly in apex predators. These organisms prefer large spans of land, so when a habitat is divided, their chances of survival are decreased.

Question 18

What is a solution to preexisting habitat fragmentation?

Answer 18

Habitat corridors (bridges of simulating habitat, and connecting fragmented areas) help to maintain genetic diversity within populations.

Question 19

Explain how natural disruptions impact an ecosystem.

Answer 19

Natural disruptions often alter which species benefit in certain environments. They can then affect the food chain, and accordingly, the trophic cascade.

Question 20

What is the geologic time scale?

Answer 20

The geologic time scale (GTS) is a system of chronological dating that classifies geological strata (stratigraphy) in time.

Question 21

What is migration and why does it occur?

Answer 21

Migration is the seasonal movement of animals, and is an adaptive response to the environment.

Question 22

How do organisms adapt to their environment?

Answer 22

Incremental changes on the genetic level allow organisms to adapt to their environment. However, for this to occur, the advantageous gene must be present before the environment changes.

Question 23

Explain the cause and effect of the peppered moth evolution.

Answer 23

The peppered moths were originally white with black specks. However, there were a few that were darker. Air pollution by humans caused the trees that the lighter moths inhabited to darken, and natural selection allowed the organism to adapt to its new environment. The lighter moths were hunted more easily once they didn’t blend in, and in contrast, the darker ones began to populate as they could camouflage themselves. Thus is why the peppered moths are now darker.

Question 24

How does genetic diversity and adaptation relate?

Answer 24

The more genetically diverse a given species is, the better equipped it is to adapt, should its environment be altered.

Question 25

How did dinosaurs go extinct 65 million years ago?

Answer 25

An asteroid collided with the earth, causing a change in climate - a climate which the dinosaurs were not equipped to thrive in. The environment went from being a very hot, dry one to a much cooler one. The dinosaurs weren’t suited for these new temperatures, so their species went extinct.

Question 26

What is ecological succession?

Answer 26

Ecological succession is a gradual process that describes the change in the structure of a community over time; one type of community succeeds or replaces the other. This is typically characterized by changes in the predominant plant community. This leads to changes in habitat and thus wildlife.

Question 27

What are the two different types of ecological succession?

Answer 27

Bare Rock > Soil > Grasses > Shrubs > Shade Intolerant Trees (Pines) > Shade Tolerant Trees (Oak)

Primary Succession -
An either anthropogenic or natural disruption occurs, which is so big that the cycle starts all over again with bare rock. Nothing survives these disturbances, sending the ecosystem back into primary succession.

Secondary Succession -
An either anthropogenic or natural disruption occurs that brings the ecosystem to one of its lower levels (soil, grasses, shrubs, etc.), but never back to bare rock. That is where this differs from primary succession.

Question 28

What are keystone species?

Answer 28

Keystone species are species whose activities have a particularly significant role in determining community structure. In other words, their roles support many other organisms in the community (ex. sea otters, ecosystem engineers like beavers that create dams, pollinators)..

Question 29

What is something we can do to protect biodiversity in communities?

Answer 29

• Set up bird and bat houses
• Eradicate weeds on your property
• Leave native plants undisturbed
• Conserve water and reduce irrigation
• Maintain old standing dead trees (provide nest cavities for many species)
• Use natural products like BT (Bacillus thuringiensis) for pest control

Question 30

Why are pioneer species so capable of moving into unoccupied habitat and adapting so quickly?

Answer 30

Pioneers are able to outcompete established vegetation that survived the disturbance, they have broad ecological tolerance, they’re adaptable and can pass on beneficial genetic traits quickly, and over time they alter conditions that will make the environment more favorable for new species (ex. adds nitrogen to the soil).

Question 31

Where does species richness occur?

Answer 31

Species richness tends to be higher in mature communities than a newly disturbed ones. The more mature and stable an ecosystem is, the greater the diversity of habitats and different kinds of niches organisms can fill, so the more species will be present.