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Bios 230 > Exam 2 > Flashcards

Exam 2 Flashcards

0
Q

Physical Limitations to Life

A 
Temperature (Heat, Cold)
Water
Gas exchange
Light
Body size
Metabolism (Energy acquisition, Energy use)
Nutrient acquisition
Waste elimination
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1
Q

Physical Ecology of the Organism

A

The physical environment can affect abundance and distribution of species

Organisms adapt to their environment

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2
Q

Temperature

A

Enzymes work best in a narrow temperature range
Freezing destroys cells
Heating de-natures proteins
Temperature affects water balance
Water balance affects temperature
Light levels affect temperature
Temperature affects metabolism
Organisms regulate their body temperatures
Several different strategies are used (slides 10-17, 20-21 lec 9)

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3
Q

Temperature

Cold-blooded/warm-blooded:

A
  • animals are cool/warm to the touch
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4
Q

Temperature

Poikilotherm:

A
  • body temperature varies

slide 24 lec 9

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5
Q

Temperature

Homeotherm:

A
  • body temperature stays constant
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6
Q

Temperature

Endotherms:

A
  • generate heat internally via metabolism
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7
Q

Temperature

Ectotherms:

A
  • require an external heat source
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8
Q

Organisms gain and lose heat many ways

A

Conduction
Radiation
Convection
Evaporation

(Slide 28 lec 9)

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9
Q

Conduction:

A
  • Two objects in direct contact

E.g. a lizard basking on a hot rock

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10
Q

Radiation

A
  • Energy gained as light —> heat

- Energy lost as heat

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11
Q

Convection

A
  • Heat transfer between 2 bodies through a liquid or gas layer
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12
Q

Evaporation

A
  • Water requires much energy to become gas
  • Water can remove excess heat from the body
  • But water loss can lead to dehydration —> over-heating
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13
Q

Counter-Current Heat Exchange: Staying Warm

A

Animals in cold climates could radiate significant heat through limbs (a)

Run warm arterial blood next to colder venous blood to warm it up (b)

(Slide 29 lec 9)

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14
Q

Counter-Current Heat Exchange: Staying Cool

A

Evaporation through nose/mouth rete cools venous blood before it returns to heart

Run warm arterial blood past cooled venous blood

Rete cools blood before it reaches the rest of the body

(Slide 30 lec 9)

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15
Q

There is a relationship between metabolic rate and rate of acceleration of chemical reactions

A

This is the temperature coefficient, a.k.a. Q10

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16
Q

The Q10 shows…

A

The Q10 shows the effect of temperature on the organism’s function

For ectotherms, metabolism (O2 use) increases with temperature

As the organism warms up, it becomes more active (uses more oxygen)

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17
Q

Q10 =

A

= the rate of biological processes generally increases 2-4 times per each 10°C increase (in normal physiological range)

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18
Q

Organisms have the ability to acclimate to new environmental conditions

A

Acclimation takes time; sudden change can lead to death

Acclimation can allow the organism to tolerate higher/lower temperatures than it normally would

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19
Q

Organisms can adapt to cold

A

Fish have developed antifreeze proteins

Plants have multiple adaptations including antifreeze proteins, supercooling, ice crystal nucleating agents OUTSIDE of cells.

Reptiles and invertebrates can supercool (no ice crystals form) due to glycoproteins

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20
Q

Size and Shape of Organisms

A

Size of organisms affects aspect of their lives

Larger animals have relatively less surface area (to volume) than smaller animals

The smaller “organism” has relatively more surface area

The larger “organism” has relatively less surface area

(Slide 38-42)

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21
Q

Surface area is important for:

A

Gas exchange
Heat absorption
Heat loss
Water loss

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22
Q

Surface Area

Leaf size and shape affect:

A

Heat exchange
Transpiration
Photosynthesis

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23
Q

Photosynthesis

A

6 CO2 + 12 H20 –> C6H12O6 + 6 O2 + 6 H2O

2-part process:

Light reaction: sun needed directly to produce ATP and NADPH

Dark reaction: CO2 made into simple sugars (G3P, glucose, starch); can occur without sunlight

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24
Q

Stomata

A

Stomata let CO2 in

Can close to minimize water loss

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25
Q

Photosynthesis in C3 plants

A

Rubisco enzyme catalyzes reaction to form 3-PGA

Rubisco enzyme can cause O2 and RuBP to react, producing CO2

A competing reaction; reduces plant efficiency

(Slide 49 lec 9)

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26
Q

Photosynthesis in C4 plants

A

2-step process involving different leaf anatomy:

  • PEP converts CO2 to malate, aspartate, in mesophyll cells
  • Compounds converted to CO2 in bundle sheath cells, then normal C3 process
  • PEP does not interact with O2 as RuBP does in C3 plants

(Slide 50 lec 9)

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27
Q

Photosynthesis in C4 plants

Pro vs Con

A

Higher rate of photosynthesis in C4 plants (than in C3 plants)

More carbon fixed per unit of “open stomata time” than in C3 plants

Greater water efficiency in arid environments

But C4 plants use more energy than C3 plants (due to production costs of making PEP)

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28
Q

Photosynthesis in CAM Plants

A

Similar to C4 plants, but carbon fixation and Calvin cycle occur in the same cells

Timing of reactions is different: stomata open at night (CO2 in, stored), close during day. CO2 is converted to sugars during the day.

Cacti and succulents

(Slide 52 lec 9)

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29
Q

Photosynthesis in CAM Plants

Pro vs Con

A

CAM pathway for CO2 fixation is less efficient, slower than C3 or C4

CAM conserves water by only opening stomata (water loss) at night

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30
Q

Body Size Affects Organismal Structure and Function

A

Larger organisms need stronger support structures to support their weight

Larger animals need thicker bones

Larger trees need thicker trunks

Size may be limited by factors other than bone strength

Heat is harder to remove in larger (volume) organisms

Size may be limited by factors other than bone strength

(Slide 56,57 lec 9)

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31
Q

Birds Have Very Efficient Lungs

A

First inhalation: Air enters mesobronchus

Enters caudal air sacs

First exhalation: Air is exhaled from air sacs through parabronchi

Second inhalation: pulls air through cranial air sacs

Second exhalation forces air from body

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32
Q

Water Transport in Plants

A

~95% of water loss in plants occurs through leaves

But large surface area is desirable to capture light

Leaves may have coatings to minimize water loss

But how to let CO2 in for photosynthesis?

  • Special openings = stomata
  • Allow CO2 in, water vapor out
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33
Q

Water Transport in Plants

Plants need ways to carry water from roots to leaves I:

A

Roots collect ions

Concentration gradient draws water into cells

Creates positive pressure in xylem tissue

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34
Q

Water Transport in Plants

Plants need ways to carry water from roots to leaves II:

A

Water is lost through leaf stomata via transpiration

Creates vacuum in xylem tissue

Pulls water up

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35
Q

Terrestrial Life Needs to Control Water Loss

A

Gas exchange requires contact between air and moist membranes

Potential water loss

How to keep from drying out?

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36
Q

How to Control Water Loss

A
  1. Reduce rate of water loss
    - or-
  2. Maintain more water in body
    - or-
  3. Tolerate water loss from body
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37
Q

How to Control Water Loss

1. Reduce rate of water loss

A

Evolve a better skin

Evolve adaptive behavior

  • Become inactive during hot, dry periods
  • Be active at night
  • Seek moist conditions
  • Hang out in burrows
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38
Q

How to Control Water Loss

2. Maintain more water in body

A

Excrete highly concentrated urine (lose less H2O)

Produce dry feces

Use metabolism to produce water from food

Drink lots and store it

Condense breath to maintain moisture

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39
Q

How to Control Water Loss

3. Tolerate water loss from body

A

Evolve dehydration tolerance

Get big: warm up more slowly; radiate heat at night

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40
Q 
Water Balance in Fishes
Saltwater fishes (hypoosmotic):
A
  • High salt concentration in surrounding water
  • Tendency toward dehydration (water lost via osmosis)
  • Actively drink saltwater to re-hydrate; tendency to gain salt
  • Concentrated urine expels salt, retains water
  • Active removal of salt through gills (uses energy)

(Slide 70, 73 lec 9)

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41
Q 
Water Balance in Fishes
Freshwater fishes (hyperosmotic):
A
  • Low salt concentration in surrounding water
  • Water enters fish via osmosis
  • Salt is lost by diffusion across gills
  • Water removal: large amounts of dilute urine
  • Active uptake of salts through gills (requires energy)

(Slide 71,72 lec 9)

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42
Q

Eliminating Wastes

A

Proteins and amino acids are digested and break down into nitrogen-containing molecules:

  • Ammonia
  • Urea (urine)
  • Uric acid (highly concentrated nitrogen waste)

These compounds can build up and become toxic
Organism needs to remove them
(Slide 4 lec 11)

Organisms may evolve tolerances to high levels of nitrogen compounds
May occur by converting NH3 to less harmful substance

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43
Q

Eliminating Wastes

Ammonia

A
  • Ammonia is the form usually used in fish, aquatic invertebrates
  • Ammonia dissolves quickly in water
  • Released through gills
  • Ammonia can be detected by other organisms
  • Sharks maintain high levels of urea in their blood
  • Prevents water loss (to surrounding saltwater)
  • Prevents need to drink (salt) water to maintain water balance
  • Prevents need to use energy to remove salt from the body
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44
Q

Energy: Food Storage

A

Fat is good

More fat = better chance of surviving hard times

Organisms exposed to regular starvation events evolve the ability to survive starvation better

(Slide 12, 13 lec 11)

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45
Q

Energy: Metabolism

There are several pathways to break down glucose

A

Fermentation
Krebs/Citric Acid Cycle

All organisms lose energy:

  • Heat
  • Excreted waste products
Organisms need a certain baseline amount of energy just to live
They need additional (net) energy to:
-Grow
-Reproduce
-Support additional activity
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46
Q

Energy: Metabolism

Organisms need energy to:

A

Maintain
Move
Grow
Reproduce

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47
Q

Fermentation

A

= is anaerobic, not very efficient

1 molecule of glucose produces 2 molecules of ATP

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48
Q

Krebs/Citric Acid Cycle

A

= is aerobic, oxygen is necessary for process to occur

1 molecule of glucose produces 36 molecules of ATP

18 times more energy!

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49
Q

Energy: Metabolism

Metabolic rate

A

= total amount of energy used in a given time

Often measured by O2 used or CO2 produced in a given time

Metabolic rate increases with activity

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50
Q 
Energy: Metabolism
Respiratory Quotient (RQ)
A

Carbohydrate and lipid breakdown produces a fixed amount of energy per liter of O2 used

Respiratory Quotient (RQ) measures energy produced by carbohydrates and lipids

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51
Q

Energy: Metabolism

Basal/Standard metabolic rate =

A

The amount of energy an organism uses when at rest and not stressed

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52
Q

Energy is the Basis for Evolutionary Tradeoffs

A

Energy intake is limited

Adaptations that require energy will have to get it from the organism’s energy budget

Energy use in one area may preclude it in another

(Slide 24 lec 11)

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53
Q

Energy is the Basis for Evolutionary Tradeoffs

Why do northern birds lay more eggs than tropical birds?

A

Food is more abundant in north
More biodiversity in tropics = more competition in the tropics
More energy needed to compete, find food, avoid predators
Less energy available to produce eggs

(Slide 27 lec 11)

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54
Q

Animals and their Resources

Autotrophs

A

= organisms that make their own food

Plants (photosynthesis)

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55
Q

Animals and their Resources

Heterotrophs

A

= organisms that must consume other organisms for food

Animals

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56
Q

Heterotroph classifications

A 
Predators (carnivores)
Herbivores (grazers)
Omnivores (a little of everything)
Parasites
Decomposers
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57
Q

Specialists

A
  • focus on one or very few food types
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58
Q

Generalists

A
  • eat a wide variety of food types
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59
Q

Life History

A

= the lifetime pattern of growth, development, and reproduction of an organism

Organisms don’t live in a world of unlimited resources; they have to make tradeoffs

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60
Q

Life History

Fitness

A

Fitness = product of organism’s viability x fertility

Fitness = survival x reproduction over a long, complex life

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61
Q

Life History Tradeoffs

A 
Modes of reproduction
Age at reproduction
Timing/frequency of reproduction
Resources allocated to reproduction 
Number of eggs/offspring/seeds
Size of eggs/offspring/seeds
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62
Q

Life History

Adaptations of an organism that affect life table values of:

A

age-specific survival

fecundity (reproductive rate, age at maturity, reproductive risk)

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63
Q

fecundity

A
  • (reproductive rate, age at maturity, reproductive risk)

- (number of offspring per reproductive episode)

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64
Q

Some Life History Traits

A

Maturity (age at first reproduction)
Survival to breeding age
Annual adult survival/mortality (average of population)

Clutch size
Clutches per year
Egg weight
Relative clutch mass (weight of all eggs)

Parity (number of reproductive episodes)
Fecundity (number of offspring per reproductive episode)

Mortality (end of life)

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65
Q

Parity

A
  • (number of reproductive episodes)
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66
Q

Senescence

A
  • (aging; deterioration with age)

= gradual deterioration that comes with age

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67
Q

Life History

Many types:

A

Bacteria reproduce once (fission); no juveniles/adults

Some insects are univoltine: one reproductive event per year, then death

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68
Q

Life History: Semelparity

A

One reproductive event, then death

Lots of offspring/seeds all at once, then parent dies

A “boom or bust” strategy

Ex. Brown Antechinus, Chinook Salmon

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69
Q

Life History: Iteroparity

A

Multiple reproductive events

A few offspring each season

A “quality over quantity” strategy

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70
Q

Tradeoffs

A

Why do semelparous animals die after reproducing?
Reproduction is very stressful, leads to death
But there is a tradeoff: greater offspring output

Resources are limited
How does the body use them?
Balance between growth, survival, reproduction

(Slide 16, 18, 20-23, 26 lec 12)

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71
Q

Reproduction is Costly!

A

Increased reproduction –> decreased survival

Decreased reproduction –> increased survival

Fitness requires reproduction

Reproduction can be costly for the individual

Reproduction can shorten lifespan

Reproductive costs limit evolution

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72
Q

Lack’s Hypothesis

A

Selection will favor the clutch size that produces the most surviving offspring

The number of surviving offspring should be maximized at an intermediate clutch size

(Slide 27, 29-31, 33, 34 lec 12)

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73
Q 
Problems with Lack’s Hypothesis
# 1
A
  1. Lack’s hypothesis assumes no tradeoff between reproductive effort in one year vs. survival/reproduction in future years
    - If reproduction is costly, reduce current investment and hold back some reserves for next time
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74
Q 
Problems with Lack’s Hypothesis
# 2
A
  1. Lack’s hypothesis assumes only the effect of clutch size in determining offspring survival
    - But being from a large clutch may have delayed maternal effects into future generations
    - Clutch size affects offspring survival and offspring reproduction
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75
Q 
Problems with Lack’s Hypothesis
# 3
A
  1. Discrepancy between Lack’s predictions and observations may be due to lack of adequate controls
    - Clutch size is highly plastic, not strongly genetic
    - Birds appear to optimize their own clutches by conditions in any given year
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76
Q

Optimization of the trade-off between growth and reproduction:

A

(Slide 38-42 lec 12)

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77
Q

Optimal Compromise Between Size vs. Number of Offspring

A

Assumption #1: tradeoff between size vs. number of offspring

Assumption 2: Above a minimum size, larger offspring will survive better than smaller ones

Parental fitness from a single clutch = (# offspring in clutch) x (probability that an individual offspring will survive)

(Slide 43-48 lec 12)

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78
Q

Alternative Life History Strategies

Different strategies depending on:

A
  • How variable is the environment
  • How long does the organism live
  • How many times does the organism get to reproduce over the course of a lifetime

r-strategies vs. K-strategies

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79
Q

Alternative Life History Strategies

r-strategists:

A

Short lives
Rapid development and reproduction early in life
Many offspring
Low survival of offspring (many born but most die)
Small body size
Minimal/no parental care
Live in unpredictable environments
Environmental resources usually not limiting (population is controlled by factors such as weather)

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80
Q

Alternative Life History Strategies

K-strategists:

A

Long lives
Slow growth
Multiple opportunities to reproduce
Relatively fewer offspring per reproductive episode
Larger offspring
Better survival of offspring
Parental care typical (animals); large seed size (plants)
Mortality affected strongly by population density
Population regulated by resource limitation

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81
Q

Aging

A

If population is shielded from disease and predation, aging can occur

Senescence = gradual deterioration that comes with age

Mortality increases with age

Fecundity declines with age

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82
Q

Why do organisms age and die?

A

Aging/Senescence = late-life decline in individual fertility and chance of survival

(Slide 56 lec 12)

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83
Q

Rate-of-Living Theory of Aging

A

Aging = accumulated damage to cells/tissues

Organisms have evolved to repair/resist damage and have reached biological limit of repair abilities

Aging rate should be correlated with metabolic rate

Species should not be able to evolve longer lifespans under selection (already maximally adapted)

84
Q

Evolutionary Theory of Aging

A

Aging = failure of organisms to repair accumulated cell/tissue damage

Repairs are incomplete and caused by deleterious mutations or tradeoffs between repair and reproduction

Natural selection is weak late in life; late-acting mutations accumulate with age

85
Q

Antagonistic Pleiotropy Theory of Aging

A

Mutations conferring fitness benefits early in life and fitness costs later in life can balance out and be advantageous

Individuals with these alleles experience early benefit without paying the late cost

Such an allele can increase fitness of carrier despite apparent low benefit and high cost

86
Q

Is there an Evolutionary Explanation for Menopause?

A

Women’s fertility declines earlier and faster in women than in men
Why stop reproduction at ~50 if life continues for many years after (~80)?

  1. Menopause is a non-adaptive artifact due to recently lengthened lifespans
  2. Menopause is a life-history adaptation associated with fitness gains of grandmothers providing care to grandchildren (grandmother hypothesis)

(Slide 60 lec 12)

87
Q

Populations

A

Population = a group of individuals that regularly share genes

Also can be a group of members of the same species that live in the same area

88
Q

How abundant are organisms?

Abundance

A

: number of individuals in the population

89
Q

How abundant are organisms?

Population density

A

= number of organisms in a given area

90
Q

How abundant are organisms?

Crude density

A

= number of organisms in a given area not accounting for distribution differences

Not all organisms in a population are distributed evenly

91
Q

Spatial Distribution of Individuals in a Population

Random:

A

An individual has an equal probability of occurring anywhere in the area

Due to neutral interactions between individuals and environment

(Slide 5, 6 lec 14)

92
Q

Spatial Distribution of Individuals in a Population

Uniform:

A

Individuals are uniformly distributed throughout the environment

Due to local depletion of resources (nutrient/water limitation in plants) or antagonistic interactions among individuals (territoriality)

(Slide 6, 7 lec 14)

93
Q

Spatial Distribution of Individuals in a Population

Clumped:

A

Individuals occur in groups

Due to patchy habitat (animals congregate around a patch of good food) or social groupings (animals are attracted to each other)

(Slide 6, 8 lec 14)

94
Q

How abundant are organisms?

Ecological density

A

Ecological density: takes uneven distribution into account

Number of individuals per available living space, not just number per hectare

Hard to estimate

(Slide 10-15 lec 14)

95
Q

Lincoln (Peterson) Index

A

N = total population (what you want to find out)

M = known number of marked animals

n = total animals captured in the second trapping

R = marked animals re-captured in the second trapping

96
Q

Lincoln (Peterson) Index formula

A

N n
M = R

Re-arrange to get:

		N = nM
			     R

Total population = (total # captured after marking)(# marked)/# marked recaptures

97
Q

Population size changes as a function of several factors:

A 
Birth rate
Death rate
Fertility rate
Age structure
Sex ratio
Immigration/Emigration
98
Q

Populations

A

Age structure affects population growth

Important age classes (stages):
Pre-reproductive
Reproductive
Post-reproductive

Each age group = a cohort

Populations with higher % of younger cohorts will expand more rapidly

99
Q

Sex Ratio

A

Sex ratios affect population growth

Primary sex ratio = ratio at conception

Secondary sex ratio = ratio at birth

These may be different!

Number of females in the population controls how quickly or slowly the population will grow

100
Q

Populations can grow in several ways:

A

Linear growth—

Exponential growth—

Logistical (sigmoidal) growth—

(Slide 25 lec 14)

101
Q

Linear growth—

A

the population increases steadily over time

102
Q

Exponential growth—

A

the population grows at an exponential rate

103
Q

Logistical (sigmoidal) growth—

A

population experiences exponential growth, then levels off

104
Q

Calculating how a population will grow:

A

Nt = size of original population

λ = net reproductive rate (average number of kids per generation)

Nt+1 = population in the next generation

N= number
t = time (which generation)
105
Q

Calculating how a population will grow in the future:

A

Nt+1 = λ (Nt)

Future population size = (Net repro. rate) (Original pop. size)

106
Q

Populations

λ

A

If λ >1.0, population will increase

If λ < 1.0, population will decrease

If λ = 1, population remains stable

(Slide 29 lec 13)

λ = net reproductive rate

λ = (# kids produced) x (probability that kids survive to adulthood)

Total # of kids produced = fertility

107
Q

Populations

Exponential growth leads to:

A

Crowding, less shelter

Starvation

Increased disease risk

Increased predation risk

Large Numbers Attract Predators

108
Q

Populations: Exponential Growth

A

Fewer offspring, lower survival

Smaller offspring, reduced adult survival, fertility

(Slide 34-41 lec 14)

109
Q

Describing Exponential Growth

A

The exponential growth equation: Nt = N0e^rt

N0 = initial population size 
Nt = number of individuals after “t” time
e = ~2.72 (natural logarithm base)
r = instantaneous per capita growth rate (intrinsic rate of population growth)
110
Q

In an exponential growth situation, the rate at which individuals are added to the population is:

A

dN = rN
dt

This is the derivative of the exponential equation,
Nt = N0e^rt

r = instantaneous per capita growth rate (intrinsic rate of population growth)

N = population size

dN varies according to population size
dt

111
Q

dN = rN

dt

A

(rate of change in population size) =
(contribution of each individual) x
(number of individuals in the population)

112
Q

r =

A

r = the individual (per capita) contribution to population growth

r = the difference between births and deaths (averaged over population as a whole)

r = (b-d)

113
Q

Geometric Growth

A

Most populations don’t grow continuously

They are seasonal: increases and decreases depending on the season

Geometric growth = population change over discrete time intervals

114
Q

Rate of geometric growth

A

Rate of geometric growth = λ = (population in current year) / (population in previous year)

λ = Nt+1/Nt

where t = time

The size of a population through a single time interval can be calculated by re-arranging equation to

Nt λ = Nt+1

115
Q

To project the growth of the population at specific time

A

Nt λ = wNt+1

To project the growth of the population at specific time intervals:
N1 = N0 λ
N2 = N0 λ2
N3 = N0 λ3

To project the growth of the population over many time intervals, re-arrange to get:

Nt = N0 λ^ t

116
Q

Geometric vs exponential growth

A

The equation for geometric growth,

Nt = N0 λ^ t

is the same equation as the one for exponential growth….

Nt = N0e^rt

….except that λ replaces e^r

The difference between geometric and exponential growth is that:

Geometric growth: you want to know the population at discrete time intervals

Exponential growth: you want to look at the overall trend

(Slide 53 lec 14)

117
Q

Intrinsic Rate of Increase

A
  • rm = intrinsic rate of increase (Malthusian parameter)
  • Maximum possible growth rate under ideal conditions
  • the exponential rate of increase of a population with a stable age distribution
  • Most populations don’t have a stable age distribution!
  • rm is more useful for identifying environmental conditions affecting population growth than as an accurate predictor of population growth

-rm = intrinsic rate of increase
= exponential rate of increase of a population with a stable age distribution
-Most populations don’t have a stable age distribution!
-R0 = net reproductive rate (fecundity x survival of newborns)

118
Q

Survival and Fertility Decline in Crowded Populations

Survival:

A 
Survival is reduced by:
Limited food
Increased waste
Increased vulnerability to predators
Increased stress
Disease
119
Q

Survival and Fertility Decline in Crowded Populations

Fertility:

A

Fertility is reduced by:
Limited food for adults
Increased behavioral interactions (fights, stress)
Smaller adults due to competition during adolescence

120
Q

Limiting factor

A

= any environmental factor that limits the abundance or distribution of an organism

Perfect Conditions Rarely Exist Forever!

Some limiting factors:
Space
Food
Disease
Predation
121
Q

Population Limits

A

Limiting factors affected by population size = DENSITY-DEPENDENT

As population grows exponentially, effects of crowding slow growth, and population ultimately stabilizes

(Slide 63, 64 lec 14)

This self-limiting process can be described using the logistic model

Logistic model is based on linear relationship between density and net reproductive rate

122
Q

Population Limits

Logistic model

A

Uses the variables:
r = the intrinsic rate of increase
K = the carrying capacity of the environment

dN = rN (K-N) =
dt K

dN = rN (1-N)
dt K

(Slide 68, 70, 71 lec 14)

123
Q

Density Regulated Populations May Show Chaotic Patterns

A

Fluctuations can occur

S-shape is not always smooth

Some causes:
Weather
Small population fluctuations due to changing conditions

(Slide 75-77 lec 14)

124
Q

Density-Independent Factors Affecting Population Growth

A 
Factors that are independent of population density:
Temperature
Rainfall
Snowfall
Fires
Floods
Droughts

(Slide 79 lec 14)

125
Q

Life Tables

A

Life tables provide a schedule of age-specific mortality and survival

Start with a cohort of organisms (all individuals born at the same time)

Track individuals throughout their lives until death

Observe trends in mortality

126
Q

Life table exponents

A 
X = Age (in years)
Nx = Number of individuals from original cohort alive at age “x”
nx = Number of individuals from original cohort alive at age “x”
lx = Probability of surviving to age “x”

dx = Number of individuals that died during any time interval

qx= Age-specific mortality rate

bx = Ave. # of females born to females in each age group

lx bx = # females born in each group adjusted for mothers’ survivorship (R0 = sum of lx bx; = net reproductive rate)

(Slide 82-89 lec 14)

127
Q

How to get lx

A

no/no
n1/no
n2/no
Etc…

(Slide 83 lec 14)

128
Q

How to get qx

A

do/no
d1/n1
d2/n2
Etc…

(Slide 85 lec 14)

129
Q

Survivorship Curves

A

3 idealized types:

High survival throughout life until heavy mortality at end (Type I)

Survival rates do not vary with age (Type II)

Extremely high mortality early in life (Type III)

(Slide 91-97 lec 14)

130
Q

Survivorship Curves—Type I

A

Mortality is concentrated toward the end of life (older organisms)

Risk of dying is higher for older organisms

lx = proportion of cohort surviving to age class “x”

(Slide 93 lec 14)

131
Q

Survivorship Curves—Type II

A

Mortality is relatively constant throughout life

Risk of dying is about the same at any age

(Slide 94 lec 14)

132
Q

Survivorship Curves—Type III

A

High mortality levels early in life, but high chance of survival if you make it though childhood

Many offspring produced, most die in infancy

Common in nature

(Slide 95 lec 14)

133
Q

Populations

Distribution of a species

A

Distribution of a species = where it can be found

Populations are small, geographically separate groups of the species

(Slide 4, 5 lec 14)

134
Q

Dispersal and Migration

Dispersal:

A
  • how individuals spread away from each other

The way individuals spread away from each other

Individuals often disperse when they mature

They can enter vacant habitat

They can enter a different population

135
Q

Dispersal and Migration

Migration:

A
  • Mass movement of large numbers of species from one place (population) to another
  • Usually involves a “round-trip”

Individuals can migrate between populations:
Allows individuals to find:
new food sources
unoccupied territory
mates

Permits gene flow between the populations
Reduces potential for inbreeding
Reduces chances that populations will evolve on separate paths

Migrations occur more often between patches that are close together; less often between patches that are far apart

The more patches in the network, the higher the occupancy rate in the patches

136
Q

Home range

A

= where an individual animal spends at least part of its time

Home Range Size is Related to Energy Requirements

137
Q

Territory

A

= the area that an animal actively defends

138
Q

Factors affecting home range size:

A

Diet
Body size
Food distribution

139
Q

Home Range Size is Related to Energy Requirements

A

Carnivores need larger ranges than herbivores

Larger animals use more energy than smaller animals

Animals with greater energy needs (carnivores, large animals) require larger ranges

(Slide 13-19 lec 14)

140
Q

Populations and Meta-Populations

Meta-population

A

= all of the smaller populations considered together; small populations linked by migration

141
Q

Metapopulation Characteristics

A
  1. Spatially separate breeding populations
  2. Each individual sub-population could go extinct at any time
  3. Re-colonization is possible
  4. Local dynamics are different in the sub-populations (e.g. population size, growth rate)

(Slide 23, 24 lec 14)

142
Q

Meta-populations

Sub-populations can be:

A

A SOURCE of new individuals: sub-population experiences net growth

A SINK (net drain) of individuals: sub-population cannot maintain its size without immigration from other populations

(Slide 23, 26-30 lec 14)

143
Q

A SOURCE of new individuals:

A

sub-population experiences net growth

144
Q

A SINK (net drain) of individuals:

A

sub-population cannot maintain its size without immigration from other populations

145
Q

Importance of Metapopulation Dynamics in Conservation Biology

A

Larger populations are less likely to go extinct

More populations mean less likelihood of extinction

Migration means suitable habitat can be (re-) colonized

Preserving as many sub-populations as possible means preserving genetic diversity of species as a whole

(Slide 33-38 lec 14)

146
Q

Allee Effect

A

As population declines, mates are harder to find

As mates are harder to find, reproduction decreases

As reproduction decreases, population continues to decline

147
Q

Allee Effect

Especially problematic for species:

A

With large territories (might not encounter mates at lower densities)

Lekking species (MIs, prairie chickens)

Cooperative breeders (African wild dogs)

148
Q

The Biosphere and the Physical Environment

A

The physical environment shapes both the ecology and evolution of organisms

Determines who can live where

Climate = Long-term average weather at a given location

149
Q

Climate

A

= Long-term average weather at a given location

Shaped by global forces

Shaped by geography

Shaped by local forces

Shaped by organisms present

Shaped at a very fine scale: micro-climate

150
Q

Does climate change?

A

Yes. Many climate changes have occurred over time

Slide 5 lec 15

151
Q

Factors that Affect Climate

A 
Distance from the equator
Temperature (air and water)
Rainfall
Seasonality
Prevailing wind patterns
Ocean currents

(Slide 7 lec 15)

152
Q

Seasons

A

Earth’s axis is tilted

Northern hemisphere gets more light during summer

Southern hemisphere gets more light during our winter (their summer)

(Slide 9, 10 lec 15)

153
Q

Ocean Currents affect Climate

A

Water can hold a lot of heat
Water temperatures fluctuate less than land (air) temperatures
Ocean currents can warm or cool the surrounding air

Coriolis effect (earth’s rotation)
Wind
Ocean upwellings
Prevailing major currents:
 - Antarctic current (gyre)
 - Gulf Stream current
 - Japan current

(Slide 13-27 lec 15)

154
Q

Global Wind Patterns

Coriolis Force:

A

Effect on Global Wind Patterns

Prevailing Winds

(Slide 19-26 lec 15)

155
Q

Hadley cells

A

Air circulation in Hadley cells produces persistent global climate patterns

(Slides 22, 23, 25 lec 15)

156
Q

Greenhouse Effect

A

Some of the sun’s energy is reflected from the atmosphere and the earth’s surface

Some is absorbed by gasses in the atmosphere

These gasses trap light and radiate it towards Earth in the form of heat

(Slide 30, 31 lec 15)

157
Q

Greenhouse Effect

Some gasses trap heat better than others:

A 
CO2 = carbon dioxide
CFC’s = chlorfluorocarbons
CH4 = methane
O3 = ozone
NOx = nitrogen oxides
158
Q

Local Climates

A 
Many factors shape local climates:
Ocean proximity
Prevailing wind patterns
Local topography (e.g. mountain ranges)
Plants

(Slides 33, 35 lec 15)

159
Q

The Biological Community Can Affect the Micro-Climate

A

(Slides 36-38 lec 16)

160
Q

Factors that Affect Climate

A 
Distance from the equator
Temperature (air and water)
Rainfall
Seasonality
Prevailing wind patterns
Ocean currents
161
Q

Biomes

A

Biome = general category of community type

Characterized by plant type and animal community

Organisms in the same biome (different location) share similar characteristics

(Slide 42 lec 15)

162
Q

Biomes—Deserts

A

Low precipitation

<150-400 mm/yr.

Organisms adapted to dry conditions

Most found between 30N and 30S of equator

(Slide 33, 35 lec 15)

163
Q

Biomes—Deserts

Plants:

A 
Small/no leaves
Thick branches
May drop leaves during drought
Minimize surface-area-to-volume ratio
Stomata close during day
164
Q

Biomes—Deserts

Animals:

A

Nocturnal

Estivation (reduced activity)

Ability to tolerate water loss

Metabolic water production

Countercurrent exchange to re-condense moisture in breath

Concentrated urine

165
Q 
Biomes—Forests
Northern coniferous (pine):
A

Low rainfall
Cool temperatures
High humidity
Evergreen

166
Q

Biomes—Forests

Temperate deciduous:

A

Warm summer/cool winter
Moderate precipitation
Trees drop their leaves

167
Q

Biomes—Forests

Tropical rainforests:

A

Wet/dry season

Low soil nutrients

High decomposition rates of organic matter

High rainfall > 200 cm/yr.

Tropical/equatorial

Stable temperature

(Slide 54 lec 15)

168
Q

Biomes—Temperate Grassland
Biomes—Tropical Grassland (Savannah)
Biomes—Chaparral

A

Look up!!!

169
Q

Biomes—Oceans

A 
Salt water: 86% NaCl
Low nitrogen
Low phosphorus
Nutrients fall to ocean floor
Little mixing between top and bottom layers
70% of Earth’s surface
170
Q

Biomes—Tropical Oceans

A

Temperature differences between top and bottom layers

Thermocline: stratified temperature layers

Layers rarely mix

Oceans have low primary productivity

171
Q

Biomes—Temperate Oceans

A

More mixing

More productive than tropical

(Slide 63 lec 13)

172
Q

Biomes—Ocean Regions

Pelagic =

A

Surface

173
Q

Biomes—Ocean Regions

Neritic =

A

regions over continental shelf

174
Q

Biomes—Ocean Regions

Oceanic =

A

open ocean

175
Q

Biomes—Ocean Regions

Benthic =

A

bottom

176
Q

Biomes—Ocean Regions

Photic zone =

A

where light penetrates and photosynthesis takes place (~30 M)

178
Q

Biomes—Freshwater Lakes and Ponds

A

Water temp changes more slowly than air: daily air temps don’t affect daily lake temps

Water = highest density at 4°C

Ice = floats on water

(Slide 79 lec 15)

179
Q

Biomes—Freshwater Lakes and Ponds

Lakes are stratified:

A

Epilimnion = warm top layer

Hypolimnion = cold bottom layer

Thermocline = steep temp gradient

(Slide 74 lec 15)

180
Q

Biomes—Freshwater Lakes and Ponds

Summer:

A

Top layer warm, highly oxygenated
Nutrients on bottom of lake
Decomposition at bottom of lake depletes O2 at bottom
No mixing of layers = summer stagnation

181
Q

Biomes—Freshwater Lakes and Ponds

Fall:

A 
Top layer cools and sinks
Bottom layer is pushed up
Layers mix = overturn
-Nutrients circulate
-Temperatures mix and lake water becomes same temp everywhere
182
Q

Biomes—Freshwater Lakes and Ponds

Winter:

A

Top of lake freezes at 0°C
Bottom of lake is more dense at 4°C
Only top freezes, not the entire lake
Winter stagnation (no circulation)

183
Q

Biomes—Freshwater Lakes and Ponds

Spring:

A 
Lake top thaws
Winds circulate warming top layer
Pull up cold bottom layer
Nutrients cycle
Lake is mixed
Spring overturn
184
Q

Biomes—Freshwater Lakes and Ponds

Eutrophic

A 
Eutrophic (high-nutrient) lakes:
Higher primary productivity
Higher biomass
Lower species diversity
Lower 02 levels at bottom
Typically shallower
Typically temperate

(slide 81 lec 15)

185
Q

Biomes—Freshwater Lakes and Ponds

Oligotrophic

A 
Oligotrophic (low-nutrient) lakes:
Lower primary productivity
Lower biomass
Higher species (animal) diversity
Higher 02 levels at bottom
Typically deeper
Typically tropical

(Slide 83 lec 15)

186
Q

River Systems

A

(Slide 84 lec 15)

187
Q

Estuaries

A

Areas where freshwater (rivers) and saltwater (oceans) mix

High productivity

188
Q

Biomes—Ocean Regions

A

Pelagic = surface

Neritic = regions over continental shelf

Oceanic = open ocean

Benthic = bottom

Photic zone = where light penetrates and photosynthesis takes place (~30 M)

Phytoplankton can exist

Zooplankton can survive on phytoplankton

(slide 66 lec 15)

189
Q

Intra-specific Competition

A

Individuals are competing with other members of the same species for food, space, resources, mates

190
Q

Inter-specific Competition

A

Members of different species are competing for the same resources (space, food, water)

One species suffers due to the presence of another species.
Species may be excluded by other species (competitive exclusion).

191
Q

Inter-specific Competition: Six types of exploitative or interference interactions:

A
  1. Consumption
  2. Preemption
  3. Overgrowth
  4. Chemical interaction
  5. Territorial interaction
  6. Encounter
192
Q
  1. Consumption
A
  • (one species monopolizes a shared food resource)
193
Q
  1. Preemption
A
  • (occupation by one species prohibits another from taking root or colonizing)
194
Q
  1. Chemical interaction
A
  • (inhibits or kills other species)
195
Q
  1. Territorial interaction
A
  • (behavior of one species excludes another)
196
Q
  1. Encounter
A
  • (non-territorial; e.g. scavengers)
197
Q

Competitive Exclusion Principle

A

G.F. Gause 1934: If two species, with the same niche, coexist in the same ecosystem, then one will be excluded from the community due to intense competition.

If 2 competing species coexist in a stable environment, it is because of small differences in niche use

(Slide 9 lec 16)

198
Q

Ecological Niche

A

All of the resource and habitat requirements of a species

The role the species plays in the environment

Describes space and diet requirements of a species

(Slide 11 lec 16)

199
Q

Fundamental Niche

A

George Hutchinson
Niche as a quantifiable characteristic of a species
Range of axis variables = the limits required for a species to survive, reproduce

(Slide 12, 14 lec 16)

200
Q

Fundamental Ecological Niche

A

The total conditions, tolerances, and requirements of an organism (considered in isolation from other species)

Where the organism lives, what resources it needs, and what role it plays in the system

Needs of the organisms represented in n-dimensional hyperspace

201
Q

Realized Niche

A

Most organisms have to share their space

Conditions are not ideal

They live in the realized niche: combination of conditions and resources need to exist in the presence of other (competing) species

The part of the fundamental niche volume that does not overlap the fundamental niche of any other species

Reflects the influence of other species

No two co-occurring species may have exactly the same realized niche.

(Slide 16 lec 16)

202
Q

Niche overlap causes competition

A

(Slide 17 lec 16)

203
Q

Competitive Exclusion

A

(Slide 18, 30-33 lec 16)

204
Q

Ex. Niche warbler birds

A

(Slide 19, 20 lec 16)

205
Q

How many different competing species can be packed into an area?

A

(Slide 21, 22 lec 16)

206
Q

How do species deal with negative effects of competition?

A

Leave and find a new area
Go extinct
Co-exist in smaller populations
Evolve to exploit a different niche: character displacement

207
Q

Character displacement

A

(Slide 24-27 lec 16)

208
Q

In Two-Species Lakes

A

Benthic:
Invertebrates found on lake bottom

Limnetic:
Invertebrates found on water surface

209
Q

In Single-Species Lakes

A

Benthic:
1/2 Invertebrates found on lake bottom
1/2 Invertebrates found on water surface

Limnetic:
1/2 Invertebrates found on lake bottom
1/2 Invertebrates found on water surface

Bios 230 (2 decks)

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