Lecture 7 + 8

Question 1

Which of factor is most responsible for creating new variation for natural selection to work with?

Answer 1

Mutations – they create new variation for selection to act on. Even if a trait is fixed, a mutation could create a new variant.

Question 2

Biodiversity is great at deep sea hot vents. One type of organism you would expect to see at these vents is:

Answer 2

A chemo-autotroph

Question 3

In upwelling systems….
- Nutrient rich deep open waters move upward
- Warm water from the deep ocean always moves upward to mix with cold surface water
- Water moves faster to the north than to the south
- Deep water volcanos essentially boil water causing bubbles to rise upward from the deep ocean to the surface

Answer 3

Nutrient rich deep open waters move upward

Question 4

Which of the following statements concerning estuaries is true?
- Estuaries have a higher salt concentration than fresh water systems
- Estuaries have a lower salt concentration than fresh water systems
- Estuaries and the open ocean have equal salt concentrations
- Estuaries have a higher salt concentration than the open ocean

Answer 4

Estuaries have a higher salt concentration than fresh water systems

Question 5

True of false: Light penetration is higher in the open ocean than in coastal waters

Answer 5

True

Question 6

What percent of Earth is covered by oceans?

Answer 6

71% and is 97% of water on earth
- streams, rivers, ponds, lakes, and wetlands cover 0.25% of surface area of Earth and is 0.007% of water on Earth

Question 7

Some of the major ocean biomes

Answer 7

• DEEP ocean
• subtropical gyres
• upwelling areas
• northern latitudes
• continental shelves
• estuaries

Question 8

Below ___m, too little light anywhere in the oceans to support photosynthesis

Answer 8

200m. There is more light penetration in the open ocean than coastal waters because there is more algae, other organisms in coastal waters that block light.

Question 9

What is the average depth of oceans? What is the deepest part?

Answer 9

Average depth of 4.3km. Deepest part is 10.9km.
- 96% of the volume of the ocean is in this “deep ocean” in the dark at depths greater than 200m
- oceans are temperature stratified
- deep ocean waters are very cold (4-5ºC everywhere)

Question 10

What is the biodiversity of the deep ocean?

Answer 10

The deep ocean has extraordinary biological diversity, including worms, crustaceans, mollusks, and fish found nowhere else.

Many of the invertebrate animals are tiny, have very low metabolic rates, and possess a lifespan that may last for decades.

Question 11

With no photosynthesis (primary production), what supports animal and bacterial life in the deep oceans?

Answer 11

Mostly supported from organic material sinking from surface oceans (“rain of detritus”)

Hydrothermal vents put out chemical energy, which is harvested by “autotrophic” bacteria that can fix CO2 and produce organic matter.
- Fascinating discovery (in 1970s), and locally important. But not all that important at scale of entire deep ocean

Question 12

What does the temperature in the deep ocean do to organisms’ metabolisms?

Answer 12

Slows metabolism of bacteria and cold-blooded animals

Question 13

Which best describes a consequence of the cold
temperatures in 96% of the volume of the oceans?
A) low rates of bacterial decomposition, so large quantities of organic matter preserved
B) slow bacterial decomposition, but animals consume organic matter, so little organic matter preserved
C) low activity by both bacteria and animals, leading to massive preservation of organic matter
D) low activity by both bacteria and animals, but the input of organic matter from surface waters is so low that little organic matter is conserved

Answer 13

B) slow bacterial decomposition, but animals consume organic matter, so little organic matter preserved

Question 14

Why do bacteria not seem very important in decomposing organic matter in deep oceans?

Answer 14

Probably because of pressure in addition to cold. Also, because little organic matter survives in deep ocean long enough for bacterial populations to grow up and use it. Animals consume most of the sinking organic matter first.

Question 15

How much organic matter is stored in the deep oceans?

Answer 15

Very little, much less than in terrestrial ecosystems, although some stored in shallow ocean systems.

Oceans are very important in taking up and storing some of the carbon dioxide released by humans, but the storage is as dissolved inorganic carbon in the deep Oceans.

Question 16

How are surface ocean waters and deep ocean waters separated?

Answer 16

They are separated by strong temperature stratification.

Question 17

In very shallow waters near land, photosynthesis is often ____. Who are the primary producers?

Answer 17

High. Primary producers include phytoplankton (micro-algae and cyanobacteria), but also larger algae attached to bottom, seagrasses (vascular plants), symbiotic algae in corals.

Question 18

Seagrasses, corals, and macro-algae attached to the bottom can only live where ____.

Answer 18

Light penetrates to the bottom
- in most of the ocean, phytoplankton are dominant primary producers (including photosynthetic cyanobacteria as well as algae)

Question 19

Terrestrial biomes are structured by gradients of

Answer 19

Temperature and moisture

Question 20

Ocean biomes are structure by gradients of

Answer 20

Light and nutrients
- subtropical gyres: low nutrients, deep light penetration
- continental shelf waters and upwelling regions: low-ish nutrient inputs, shallow-ish light penetration
- productive estuaries: big range of nutrients, shallow light penetration

Question 21

Subtropical oceanic gyres

Answer 21

Large water parcels isolated from the rest of oceans by circular currents (“gyres”) for surface oceans and temperature stratification for the deep ocean

Question 22

Subtropical oceanic gyres characteristics

Answer 22

• after deep ocean, largest biome on Earth (by far!)
• cover half the surface area of the oceans (35% of the entire surface of the planet!)
• very high diversity
• very low rates of photosynthesis (lowest on planet for aquatic ecosystems, comparable to least productive deserts)

Question 23

Subtropical oceanic gyres have the clearest water on Earth and the deepest light penetration. So why is primary production so low?

Answer 23

Nutrients are extremely low (comparable to distilled water)
- although high nutrients nearby (!!) in deep ocean waters
- stratification keeps the high nutrients of the deep ocean away from surface waters
-> but photosynthesis only occurs in surface waters, due to light

Question 24

Low nutrient levels:
a) have little influence on size of phytoplankton
b) lead to small phytoplankton
c) lead to large phytoplankton

Answer 24

Lead to small phytoplankton
- high surface to volume ratio (lot of sites for enzymes to take up nutrients relative ot mass of chlorophyll)
-> long food chains –inefficient, so less production of top predator fish per unit of primary production

Question 25

Sargasso Sea

Answer 25

In addition to phytoplankton, a floating Sargassum weed (macro-algae) in the Sargasso Sea (but not other gyres)

Question 26

Upwelling

Answer 26

Result of interaction of prevailing winds interact with coastlines - brings cold, deep-ocean waters to the surface -> also nutrient rich

Question 27

Light penetration of continental shelf waters and upwelling regions

Answer 27

Relatively low (due to scatter and absorption by phytoplankton) - but the upward flux of water keeps phytoplankton buoyed in the light - high rates of photosynthesis northwest of South America and middlewest of Africa, northeast of China, northeast of USA, western Europe -> high photosynthesis also supported by mixing of nutrient-rich ocean bottom waters onto shallow continental shelves

Question 28

Upwelling ecosystems

Answer 28

- high productivity - relatively small area of the oceans (5%) - relatively low diversity - large phytoplankton - short food webs - very productive fisheries (25% of total ocean catch)

Question 29

What is the size of phytoplankton in areas with high levels of nutrients?

Answer 29

Large phytoplankton – have low surface to volume ratio (less need for enzymes to take up nutrients) - short food chains -> efficient, so high production of fish per unit of primary production

Question 30

Estuaries and coastal shelves characteristics

Answer 30

- often very high nutrients from land (and some from deep ocean) - low light penetration (suspended sediment, plus phytoplankton absorption) - often shallow, so sufficient light (even with low penetration) - high productivity - relatively low diversity (as in upwelling) - large phytoplankton (as in upwelling) - short food webs (as in upwelling) - very productive fisheries (as in upwelling)

Question 31

High latitude waters

Answer 31

Away from shore and quite productive

Question 32

Photosynthesis is moderately high in the high-latitude ocean waters because

Answer 32

The waters are stratified, but more weakly than in the subtropical gyres (allowing a balance of some nutrients from below yet sufficient light)

Question 33

Nutrients (nitrogen and phosphorous) come from

Answer 33

- river inputs from land - deep ocean (where nutrients are very high, due to slow decomposition of organic matter than sinks there) - only in the very surface of the ocean is there enough light for photosynthesis

Question 33

Photosynthesis is controlled by mixing of the surface ocean waters (in turn controlled by climate):

Answer 33

- if no mixing, no nutrients from bottom waters - if too much mixing, phytoplankton are mixed too deeply and get too little light - more wind and less heating in the higher latitude waters than in subtropical gyres, so more mixing and less stratification - but not too much mixing, so good balance between light and nutrients

Question 34

Photosynthesis is high only when

Answer 34

Both nutrients and light are high

Question 35

Comparing all the Earth (land and oceans): A) most photosynthesis is on land, but the biomass in the oceans is greater B) most photosynthesis is in the oceans, but biomass on land is greater C) photosynthesis is roughly equal on land and in the oceans, but biomass in the oceans is greater D) Photosynthesis is greater on land, but biomass is roughly equal on land and in the oceans E) Photosynthesis is roughly equal on land and in the oceans, but biomass is greater on land

Answer 35

Photosynthesis is roughly equal on land and in the oceans, but biomass is greater on land - remember that the area of the oceans is 2-fold greater - biomass of primary producers turns over much more rapidly in oceans than in forests (or even grasslands) -> days rather than decades

Question 36

Large masses of semi-isolated surface water surrounded by a circular current of water moving clockwise would...

Answer 36

Gyres in the northern hemisphere

Question 37

What is one possible explanation of why biodiversity is very high in subtropical gyres?

Answer 37

The low-nutrient status within a gyre has led to specialized adaptations

Question 38

Which of the following statements are accurate? (Choose one or more answers) - The rate of primary production is similar in the ocean and on land - Total primary production is similar in the ocean and on land - Terrestrial biomass is less than marine - Marine biomass is less than terrestrial - Total biomass is comparable on land and in the ocean

Answer 38

Total primary production is similar in the ocean and on land Marine biomass is less than terrestrial

Question 39

Which 2 properties have the greatest impact on structuring ocean biomes?

Answer 39

Light and nutrients

Question 40

You are eating dinner (an impossible burger) on the deck of a boating trip while passing through a subtropical gyre. Your ship starts to take on water. Everybody is rescued but you did not finish your food. your ship and dinner sink to the bottom of the ocean. What will be the fate of your impossible burger after 2 months? - The cold and pressure will preserve the burger - The burger will be gone because it is consumed by bacteria - The burger will be gone because it is consumed by deep sea animals - The burger will be gone because it is consumed by phytoplankton - Impossible burgers float, so it will be consumed by seagulls

Answer 40

The burger will be gone because it is consumed by deep sea animals

Question 41

Which of the following ocean biomes has the lowest primary productivity? - Estuaries - Subtropical gyres - Continental shelfs and upwelling regions - Deep ocean

Answer 41

Deep ocean. Subtropical gyres have high light penetration, but low nutrients, however there is still some productivity. No light reaches the deep ocean so there is no productivity.

Question 41

Which ocean biome has the lowest fisheries production?

Answer 41

Subtropical gyres

Question 42

What term describes a group of individuals of one species?

Answer 42

Population

Question 43

Which organism completes its entire life cycle in a single year? - An annual - A biennial - A perennial - An iteroparous perennial

Answer 43

An annual

Question 44

Which of the following choices best describes an iteroparous organism? - An iteroparous species breeds only once and invests all of its energy into reproduction. - An iteroparous species breeds many times in its life and invests all of its energy into reproduction. - An iteroparous species breeds many times and invests its energy into reproduction, growth and development. - An iteroparous species breeds only once but invests all of its energy into growth and development.

Answer 44

An iteroparous species breeds many times and invests its energy into reproduction, growth and development.

Question 45

What term describes individuals of a population that are all born within a particular period?

Answer 45

Cohort

Question 46

Guild

Answer 46

Any group of species that exploit the same resources, or that exploit different resources in related ways

Question 47

Based on the survivorship curves, which depicts circumstances where risk of mortality is greatest at older ages?

Answer 47

Type I (humans and large mammals)

Question 48

Which terms describe generalized ecological spatial patterns that may be exhibited by organisms? - Aggregated - Random - Regular - Segregated

Answer 48

Aggregated Random Regular

Question 49

When an individual male leaves a pack in search of its own territory, this is referred to as _________?

Answer 49

Dispersal

Question 50

What is a population?

Answer 50

Biological population – number of individuals of a given species in a given area (at a given time)

Question 51

Why is understanding populations important?

Answer 51

- understanding how and why populations change size gives insight into the ecological world - we need to know population sizes/changes/distributions/etc. in order to make important decisions regarding conservation and management

Question 52

How do we measure populations?

Answer 52

1. complete or total counts - impractical 2. incomplete counts - sample part of the area and extrapolate 3. mark-recapture - not very practical for deer 4. indirect counts - often used for relative comparisons -> hunter success per effort is one of the most common

Question 53

What are the 4 most basic factors that result in changes in population size?

Answer 53

1. reproduction 2. deaths 3. immigration 4. emigration

Question 54

Deterministic population modelling

Answer 54

Generalize important factors - ignore "random" factors - real populations have random factors that cause fluctuations

Question 55

Demographic processes

Answer 55

Nt+1 = Nt + B - D + I - E New population = population now + births - deaths + immigrants - emigrants -> sometimes we only consider closed populations and ignore the immigrants and emigrants part

Question 56

Birth rate

Answer 56

Number of offspring produced per individual in the population ex. if N = 100 and 200 newborns, the birth rate = 2

Question 57

Death rate

Answer 57

Proportion of individuals in the population that die ex. if N = 100 and 75 die, death rate = 0.75

Question 58

Geometric population growth Population growth rate = Lambda =

Answer 58

Lambda = 1 + (birth rate – death rate) Lambda = 1 + (b-d)

Question 59

New population at next generation =

Answer 59

Starting population * population growth rate Nt+1 = Nt * lambda

Question 60

When lambda = 1

Answer 60

Population has constant size Birth rate = death rate - on average, each individual replaces itself ex. lambda = 1 + (0.5 – 0.5) = 1

Question 61

When lambda >1

Answer 61

Population is growing Birth rate > death rate ex. lambda = 1 + (0.5 – 0.1) = 1.4

Question 62

When lambda < 1

Answer 62

Population is shrinking Birth rate < death rate ex. lambda = 1 + (0.1 – 0.5) = 0.6

Question 63

What is wrong with arithmetic growth?

Answer 63

The size of the population in the next time step = the current pop * a growth rate It would be odd if a population added the same number of individuals each time step regardless of its population size

Question 64

Geometric growth formula

Answer 64

Nt = No*lambda ^t Population size at time t = initial population size * geometric rate of increase ^ t

Question 65

Geometric and exponential growth can look similar

Answer 65

- closed system (no immigration or emigration) - geometric growth – discrete reproduction -> population size at time t can be modelled as Nt = No*lambda^t - exponential growth – continuous reproduction -> population size at time t can be modelled as Nt = Noe^rt

Question 66

Difference between geometric and exponential growth

Answer 66

Geometric – discrete reproduction Exponential – continuous reproduction Both lambda and r are used to describe how fast a population is growing

Question 67

What is r?

Answer 67

r is the per capita intrinsic rate of increase (also called exponential population growth rate) r = b – d If r > 0 then b > d and the population size grows If r = 0 then b = d and population size stays the same If r < 0 then b < d and the population size decreases When growth is exponential, r is at maximum rate (rm)

Question 68

How long would it take algae – growing exponentially – to reach the mass of the known universe?

Answer 68

Months We are growing from 1 cell to 4 × 10^67 cells -> 75 days

Question 69

What is unrealistic about exponential growth?

Answer 69

There are limits to population growth -> carrying capacity Logistic growth makes more sense

Question 70

Can a population be over carrying capacity?

Answer 70

Yes but not for long

Question 71

Where is the reproductive output per individual the highest?

Answer 71

At the beginning where there are few individuals, almost = 1, r is not being reduced much, almost at max Less competition, ample resources, less competition

Question 72

Population growth is highest at

Answer 72

middle part of logistic growth (steepest slope)

Question 73

Population size v. population growth rate

Answer 73

Looks like a dome - the population growth rate (dN/dt) increases until reaching the value of K/2, and then declines

Question 74

Life history

Answer 74

The adaptations of an organism that influence its survival, growth, and reproduction

Question 75

Some life history questions

Answer 75

How fast to grow and develop? When to metamorphose? How fast to grow? How large to grow? When to begin reproducing? How many offspring and of what size? Whether to care for offspring? How often to breed? How long to live?

Question 76

Do species have simple or complex life cycles?

Answer 76

Complex life cycles are common in insects, marine invertebrates, amphibians, and some fishes Many vertebrates have simple life cycles without abrupt transitions (Dall sheep, humans)

Question 77

Semelparity

Answer 77

Breed once and die (salmon)

Question 78

Iteroparity

Answer 78

Reproduce repeatedly during lifetime (humans, deer, tigers, etc.)

Question 79

Principle of allocation

Answer 79

The principle that if an organism invests energy to one function (e.g., growth), it reduces the amount of energy available for another function (e.g., reproduction) Trade offs

Question 80

Trade-offs between size and number of offspring

Answer 80

- the larger the investment in each individual offspring, the fewer offspring can be produced - investments: energy, resources, time - parental care, larger egg or seed

Question 81

Survivorship Curve – Type I

Answer 81

Low juvenile mortality and high mortality later in life e.g., large mammals with parental care, some plants, some invertebrates number of survivors: parallel before curving out and downward risk of mortality: exponential growth

Question 82

Survivorship Curve – Type II

Answer 82

Constant rates of mortality e.g., small mammals, many birds, lizards number of survivors: linear slope down risk of mortality: parallel line

Question 83

Survivorship Curve – Type III

Answer 83

High juvenile mortality and low adult mortality e.g., marine fishes, some plants, some invertebrates number of survivors: slide down curve risk of mortality: slide down curve

Question 84

r selection

Answer 84

abundant resources unpredictable environment density-independent mortality

Question 85

K selection

Answer 85

limited resources predictable environment density-dependent mortality

Question 86

r vs K: competitive ability

Answer 86

r: low K: high

Question 87

r vs K: body size

Answer 87

r: small K: large

Question 88

r vs K: development

Answer 88

r: rapid K: slow

Question 89

r vs K: reproduction

Answer 89

r: early K: late

Question 90

r vs K: offspring (number of)

Answer 90

r: many K: few

Question 91

r vs K: offspring (size)

Answer 91

r: small K: large

Question 92

r vs K: lifespan

Answer 92

r: short K: long

Question 93

r vs K: survivorship curve

Answer 93

r: Type III K: Type I

Question 94

Metapopulations: biological population

Answer 94

Number of individuals of a given species in a given area (at a given time) However, it can be more complicated than this

Question 95

Metapopulation

Answer 95

A set of spatially isolated populations linked to one another by dispersal ex. Imagine a situation with 2 islands If there is lots of dispersal - would function like one population If there is little or no dispersal – would function like different populations At low to moderate rates of dispersal – could function like a metapopulation

Question 96

Metapopulation dynamics

Answer 96

At any one time – there is at least one patch where conditions are good and that allows a population to persist

Question 97

True or false: Complete or total counts of populations are easy to collect and typically used for management of wildlife.

Answer 97

False because it is often very difficult to get complete counts of populations. So, managers typically use sub-sampling or indirect counts to make population estimates.

Question 98

What is necessary for determining average density of a population?

Answer 98

The total number of individuals The total size of a habitat

Question 99

In a mark and recapture study you initially collect 50 frogs. You mark and release those 50 and plan to collect again in another week. The following week you collect 50 frogs and 10 of them are from your previous mark and recapture. How large would you estimate the population to be?

Answer 99

The population is estimated to contain approximately 250 individuals

Question 100

Neurospora crassa (a bread mold) reproduces by making a pod (called an ascus) that always contains 8 spores, each of which can go on to form new individuals (each of which can then make a pod of its own). If the mold population grows geometrically from a starting size of 100 individuals, which of these equations would you use to calculate the population size of the mold after 7 generations?

Answer 100

N7 = 100 * 8^7 Consider one individual. One individual at time zero will produce 8 spores. So at time 1 the population size is 8, Those 8 descendants will each produce 8 spores so in the second generation we have 8*8=64. and so on 8*8*8*8*8*8*8 = 87 = 2097152 We then need to consider that we started with 100 individuals so 2097152 * 100 = 209715200 This is all represented by the equation N7 = 87 × 100

Question 101

True or false: The size of a population can exceed carrying capacity.

Answer 101

True because populations can be above K for a short time, but limited resources will eventually cause the population to decline.

Question 102

If birth and death rates are density dependent, then the density of a population will cycle near ______________.

Answer 102

The carrying capacity

Question 103

You are doing a research project to determine the age of maple trees in a series of 100 square meter plots. Your data are interesting because many of the trees that are the same age are not the same size, even though they are within a few kilometres of one another. Why might this be?

Answer 103

Trees are long-lived and modular organisms. As a result, some individuals may have experience competition and herbivory that has affected growth and development.

Question 104

A perennial plant (Sparaxus grandiflora) must invest resources differently when it starts to enter a reproductive stage. Which of the following choices explains how a perennial plant may deal with this? - The plant does nothing different since it is a perennial - The plant experiences trade-offs no matter if it is a perennial or annual. Therefore, it will likely have to reduce root growth and leaf development to compensate for the resources used for reproduction - The plant will not experience any trade-offs since it has evolved to reproduce and grow simultaneously - None of the above

Answer 104

The plant experiences trade-offs no matter if it is a perennial or annual. Therefore, it will likely have to reduce root growth and leaf development to compensate for the resources used for reproduction

Question 105

How does probability of reproduction change as a function of increasing leaf area?

Answer 105

Probability of reproduction increases

Question 106

A Type II survivorship curve: - Shows that mortality is constant - Shows that younger individuals have a higher death rate than older individuals - Is typical of human populations - Shows that the risk of mortality is the same regardless of age

Answer 106

Shows that mortality is constant Shows that the risk of mortality is the same regardless of age

Question 107

You have been researching species of bacteria found in the rocky intertidal zone. These bacteria are likely __________ because they live in a disturbed habitat, reproduce quickly, and invest little energy in growth or development.

Answer 107

r species

Question 108

Which survivorship curve is an elephant?

Answer 108

Type I

Question 109

Which survivorship curve is a cardinal?

Answer 109

Type II

Question 110

Which survivorship curve is an oak tree?

Answer 110

Type III

Question 111

Which survivorship curve is a salmon?

Answer 111

Type III

Question 112

Which survivorship curve is a sea turtle?

Answer 112

Type III

Question 113

Which survivorship curve is a polar bear?

Answer 113

Type I

Question 114

True or false: A metapopulation is a set of spatially isolated populations linked to on another by dispersal

Answer 114

True

Question 115

Which of the following are examples of dispersal? - The passive transport of seeds on a duck to another lake - A honey badger leaving its mothers care and going to a new area - A dandelion seed gets carried a great distance on the wind when a child blows on the seed head - A young male mountain lion seeking out its own territory

Answer 115

The passive transport of seeds on a duck to another lake A honey badger leaving its mothers care and going to a new area A dandelion seed gets carried a great distance on the wind when a child blows on the seed head A young male mountain lion seeking out its own territory