Lecture 13

Question 1

what is ecology?

Answer 1

the science of biodiversity:
- how organisms interact with each other and with their environment
- distribution and abundance of species
- structure and function of ecosystems

Question 2

how many species are there?

Answer 2

globally, too many to count. many (>85% are still unknown to science). one estimate, extrapolated from rates at which new taxa are described is 8.7 million (just eukaryotes)

Question 3

is biodiversity equally distributed across the tree of life?

Answer 3

no, 70-90% of species are bacteria

Question 4

define a populations

Answer 4

all the individuals of the same species in one place at one time

Question 5

define an ecological community

Answer 5

all the species living together in one place at one time

Question 6

define an ecosystem

Answer 6

all the species plus the non-living environment

Question 7

why do we care about species range?

Answer 7

• to understand where plants and animals can grow because they give us food, clothing, wood, medicine, etc
• predict what will happen to biodiversity as the climate changes
• predict how biodiversity will respond to habitat destruction, pollution, invasive species, etc
• to understand disease risk of microbes

Question 8

what determines where species live?

Answer 8

• dispersal
• abiotic conditions: climate, nutrients
• species interactions: competition, predation, mutualism

Question 9

what limits a species’ range?

Answer 9

• dispersal
• climactic or other inexhaustible conditions, eg temperature/salinity
• food or other exhaustible resources, eg nutrients/space
• species interactions eg competition/predation/mutualism

Question 10

the sixth extinction

Answer 10

• ongoing mass extinction, mainly as a result of human activities
• 32% of known vertebrate species (8,851/27,600 species) are decreasing in population size or range
• North American birds have declined in abundance by 29% since 1970

Question 11

Margulis

Answer 11

Lynn Margulis was an American biologist whose serial endosymbiotic theory of eukaryotic cell development revolutionized the modern concept of how life arose on Earth.

Question 12

Malthus

Answer 12

English economist and demographer who is best known for his theory that population growth will always tend to outrun the food supply.

Question 13

some species live almost everywhere

Answer 13

Mountain Lion, Puma concolor (North and South America)
Red fox, Vulpes vulpes (most of northern hemisphere and introduced to Australia)

Question 14

Some species live almost nowhere

Answer 14

American Pika,
Ochotona princeps