Midterm 1 (Lectures 1-9) Flashcards

Question

List five truths about evolution.

Answer 1

* Mutations generally do not transform an organism that is already alive * Mutations are inherited from parents to offspring. * Evolution does not occur on an individual basis, but by population * Evolution typically leads to alternate not ultimate forms * Evolution requires a selection pressure in order to occur

Answer 2

- *variable fitness among individuals - a group of individuals of one species living together - where evolutionary change is revealed

Answer 3

- Individuals (phenotypes) respond to selection pressures in their environment. Responses to selection pressures alter the relative contribution of individuals to future generations (fitness), through the process of natural selection - Reservoir of genetic information

Answer 4

- DNA is 4 nucleotides arranged in an alpha helix - Each individual has a unique sequence of nucleotides in their DNA - DNA is contained in chromosomes

Answer 5

- contains DNA in its structure | - come in matched pairs, one from each parent

Answer 6

- DNA is organized into discrete subunits called genes | - code for proteins

Answer 7

Particular location of a gene on a chromosome

Answer 8

- two or more alternative forms of a gene - result from slight differences in the DNA sequence of the gene - cause slight differences in form and function

Answer 9

an individual that has the same alleles at a particular locus on the pair of chromosomes (AA, aa)

Answer 10

- an individual that has different alleles at a particular locus on the pair of chromosomes (Aa) - If one allele is fully expressed and the other has no noticeable effect

Answer 11

Dominant allele – fully expressed (A) | Recessive allele – unexpressed (a)

Answer 12

- Worked with pea plants phenotypes - Discovered genotypes - Mendelian Inheritance

Answer 13

- breeding of two individuals results in multiple combinations of alleles - 1 allele present on each chromosome of a parent - 1 chromosome (allele) is present in each gamete produced by a parent - Gametes combine in offspring to form a new combination of alleles - use Punnett square * how genetic variation is maintained

Answer 14

all possible allele combinations from random mating of any combination of individuals in a population

Answer 15

Genotype: genetic variation within species - all genetic characteristics of an individual (set of genetic information) - morphological, physiological and behavioural - genetic characteristics are encoded in DNA - Fixed during the lifetime of an individual Phenotype: variation within genotypes - interaction of the genotype of an individual with its environment - outward expression of genes in the appearance/behaviour of an individual - Responses of individuals to environment may vary - Not Fixed during the lifetime of an individual * Individuals with the same genotype may look different under different environmental conditions

Answer 16

-the ability of a genotype to alter its phenotypic expression under different environmental conditions -There are limits to phenotypic plasticity! (Responsiveness to environmental conditions) Ex) Daphnia can only produce so much pigmentation or be transparent

Answer 17

1. Discrete, alternative forms - e.g. Social insects – such as bees and ants, two types of larvae hatch with essentially the same genetic material but queens are adults that reproduce and soldiers/workers are adults that defend the other larvae 2. Continuous variations in form (continuously varying phenotypes) -Reaction norm = relationship between response of a continuously varying trait and environmental conditions -e.g. Daphnia respond (pigmentation) to varying UV radiation A)Avoid predators → transparent (no pigmentation), vulnerable to UV B)Avoid effects of harmful UV radiation → highly pigmented, vulnerable to predators -level of pigmentation varies continuously in response to UV radiation and predator abundance

Answer 18

* is a change in the genetic composition of a population of a species over time - the match of individuals to their environment is a product of the successes and failures of their ancestors - the present form and function of individuals are specializations to their environment

Answer 19

-the change in a genetically determined trait in response to environmental conditions that enhances the ability to cope with the environment -evolutionary process that takes place in a population over many generations through natural selection -Traits can be behavioural, physiological or morphological Ex) fur colour in rabbits And seasonal leaf loss of trees

Answer 20

- the proportionate contribution of an individual to future generations (by reproduction) - Responses to selection pressures alter the relative contribution of individuals to future generations (fitness), through the process of natural selection - Number of offspring produced - Number of offspring surviving to reproductive age - Fitness is a relative term - fittest individuals leave the greatest number of descendants relative to other individuals in population

Answer 21

-jokes and memes about human stupidity, resulting in probability of that individual not passing on their genetic information to offspring Ex) man pulls tail of tiger and will probably result in their death before having any children -natural selection takes care of stupidity

Answer 22

- Colour is a heritable trait - blue is a favourable trait - higher survival and higher reproduction - leaves a higher proportion of descendants in next generation

Answer 23

- Operates on the individual - Individual variation has a genetic basis → traits are inherited - Individuals with favourable traits are more likely to reproduce; these individuals leave more descendants than others - Favourable traits are passed on to future generations at a higher frequency - Genetic composition of the population changes over generations or evolves

Answer 24

- Selection pressures: - Environmental conditions - abiotic factors - Species interactions (predators, competitors) – biotic factors - Selection pressures establish differences in fitness among individuals with different genotypes and phenotypes

Answer 25

1. Individuals of a species are not identical – genetic variation 2. Some of this variation is heritable 3. Individuals leave different numbers of descendants – varying fitness 4. Fitness depends on the interaction between an individual’s traits and its abiotic & biotic environment (The environment acts as selection pressures)

Answer 26

Selection pressures, fitness

Answer 27

Individual, population

Answer 28

Natural selection, evolutionary change

Answer 29

The genetic composition (allele frequencies) within a population does not change (~evolution does not occur) unless one of the following assumptions are broken: i. No Mutations – can create an allele ii. (Non) Random mating - among individuals in a population (certain individuals more desirable e.g. blonde individuals only mate with other blondes) *If random mating, allele frequencies will stay the same iii. No Migrations – can add or subtract from the gene pool iv. Small Populations – limited gene pool and mating opportunities, becomes less random v. Natural selection – most important! Selective pressures (or changing abiotic and biotic factors)→varying fitness among individuals → favourable traits are passed on to future generations at a higher frequency → genetic composition of the population changes over time

Answer 30

1) Stabilizing 2) Disruptive 3) Directional

Answer 31

Frequency: Both small and large sizes are removed from population Fitness: Large and small sizes are produced much less than medium. (Bell curve) Average size: Straight line indicates medium size. Ex) sickle cell anemia

Answer 32

Frequency: Medium size is removed since its most common. Fitness: Bell curve is flipped since now more large and small sizes reproduce. Average size: No medium sized offspring, mostly large and small sizes.

Answer 33

Frequency: most common situation, removes largest size Fitness: Highest fitness in small sizes Average size: In time, the population gets smaller and smaller

Answer 34

- Survival of the moth from birds depends on being camouflaged against the tree trunk - Two forms: light and dark - Colour: determined by a single gene → colour reflects genetic variation among individuals - Early 1800s – occasional dark forms, but primarily light form - Early 1900s – dark form became more common in heavily industrialized areas. Why? 1) Soot deposited on tree trunks 2) Dark colour –more favourable 3) Genetic composition of population changed over generations; More and more of the darker colour to avoid predation from birds=higher survival and fitness

Answer 35

Directional selection

Answer 36

1. Conover & Munch studied Atlantic silverside (Menidia menidia) experiments in lab by selectively removing larger fish, selectively removed smaller fish, removed fish at random and measured fish for 4 generations. Conclusion: mean weight of harvested fish declined over the 4 generations 2. Fishing pressure can significantly change the genetic composition of populations in 20-50 yrs. Size-selection is one of the primary reasons why overexploited fish populations do not recover.

Answer 37

- Smaller fish produce fewer eggs and fewer offspring | - The amount of fish available to harvest decreased over time

Answer 38

- Distinguish species based on their potential to interbreed and produce fertile offspring - implies that reproductive isolation (or genetic isolation) defines a species because reproduction is the means of transferring genetic information (DNA)

Answer 39

1) isolation: exchange of genes among individuals of a population (gene flow) stop, some individuals become reproductively isolated from other individuals 2) isolated subpopulation experiences different selection pressures (→different favourable traits → varying fitness) 3) genetic composition of subpopulation changes over generations (1o via natural selection) 4) After generations, if the isolated subpopulation can no longer interbreed with the origin population → speciation (If subpopulations can interbreed – no speciation)

Answer 40

Allopatric (geographic) speciation: individuals are geographically isolated by a physical barrier (e.g. river, mountain, unsuitable habitat) Sympatric speciation: subpopulations are isolated without geographical isolation (e.g. timing or location of breeding), *disruptive selection favours divergent phenotypes

Answer 41

- Darwin’s finches of the Galápagos Islands - Couldn’t interbreed since they changed so much (physically) - physically separated by different islands

Answer 42

- the Mias and Arrow Cichlid species of Nicaragua living in small, isolated, low productivity lakes - disruptive selection=divergent food preferences (competition) → different food and feeding habitats - Two morphotypes=different feeding morphology, body shape - Reproductive isolation=differences in courtship behaviour → non-random mating (premating) - so separate species

Answer 43

Speciation is maintained through reproductive isolation of the subpopulations...

Answer 44

mechanisms that restrict exchange of genes between subpopulations

Answer 45

1. Premating – prevent mating -Separation of mating events in space and time -Behaviour, mechanical or structural incompatibility 2. Postmating - reduced survival or reproductive success of offspring - donkey + horse can still reproduce but offspring is a mule that is sterile

Answer 46

Natural selection

Answer 47

Disruptive, directional and stabilizing

Answer 48

Allopatric, Sympatric

Answer 49

- is the part of the physical (abiotic) environment that has the greatest impact on an organism - long-term average pattern of weather

Answer 50

combination of temperature, humidity, precipitation, wind, cloudiness at a specific place and time

Answer 51

- Earth’s atmosphere intercepts solar radiation - Earth’s rotation and movement generate prevailing winds and ocean currents - result: environmental heterogeneity

Answer 52

variability in abiotic factors across space

Answer 53

Global → Regional → Local → Micro (largest to smallest spatial scales)

Answer 54

Global and regional climate patterns determine the large-scale distribution of plants and animals.

Answer 55

1) aquatic environment | 2) terrestrial environment

Answer 56

Microclimate: - Local climatic conditions do not match the general climate profiles of the larger region - Because local patterns of microclimate are the actual environmental conditions experienced by organisms → our focus

Answer 57

Dominant environment on Earth ~ 75 % of the planet’s surface is water

Answer 58

Aquatic: Low degree of microclimate variability in time and space (not as much difference in aquatic compared to land that has lots of variation in climates) Terrestrial: High degree of microclimate variability in time and space

Answer 59

Divided by salinity: saltwater (oceans) and freshwater (lakes and rivers) Divided by depth (maximum of 11km deep in oceans - mean ocean depth =3.7km

Answer 60

Solar radiation is - reflected back into atmosphere - absorbed or reflected by suspended particles (alive & dead) - absorbed by water - solar radiation declines exponentially with depth (Distinct vertical profiles of light, temperature, oxygen, pressure, etc.)

Answer 61

Direct impact: plants ○ Plants require sunlight for photosynthesis ○ Plants are restricted to top 100 m (depth, very restricted to surface) Indirect impact: animals ○ Herbivores are restricted to depths where plants reside

Answer 62

i. Lack pigment ii. Large eyes (maximum light-gathering ability) iii. Organs that produce light (bioluminescence, produce their own light to attract other organisms)

Answer 63

- Exponential decline in solar radiation with depth → decline in temperature with depth - After temperature continues to decline with depth but at a slower rate - Some form of thermal stratification occurs in all open bodies of water - Mixing of the water column can break down this gradient (e.g. winds, currents, seasonal)=important for organisms to survive stratification EX) as water cools, it becomes more dense until 4oC (max density) → 4- 0 oC is less dense - Fall: surface waters cool, become more dense, sink, creates mixing= fall turnover - Winter: surface water less than 4 degrees, less dense, keeps cold water at surface (freeze), warm water below allows for organisms to survive the winter

Answer 64

Thermocline = region with most rapid decline in temperature

Answer 65

-Oxygen diffuses from the atmosphere into aquatic environments -Oxygen produced by plants during photosynthesis ○ Restricts high concentrations of oxygen to surface waters ○ Limits respiration and metabolic activity of animals ○ Mixing of the water column can break down this gradient -further down you go in depth, the less oxygen is available

Answer 66

Greatest constraint is desiccation (drying out) ~ living cells contain 75 - 95 % water

Answer 67

Maintaining water balance

Answer 68

Soil is the foundation upon which all terrestrial life depends - Medium for plant growth - provides vertical structure for animal life - Controls the fate of water in terrestrial environments - Provides habitat for decomposers (Nature’s recycling system) - Moisture-holding capacity of the soil is critical for availability of: Water and chemical elements dissolved in soil water

Answer 69

1. Climate - directly influences the physical & chemical reactions in the soil & water availability through levels of precipitation in that area 2. Type of parent material - material from which soil develops (Physical and chemical characteristics determine properties of soil) 3. Topography -eg. Slope, level ground (more slope=less moisture it will hold) 4. Aspect – north vs south-facing sites (north may experience more precipitation than south, Differ in their exposure to solar radiation/wind) 5. Presence/absence & type of vegetation (Vegetation alters microclimates)

Answer 70

i. Light (via shading) ii. Temperature (via shading) iii. Moisture (via use) iv. Wind movement v. Structure – habitat for animals (Eg. Different bird species depend on vegetation of different heights) * Vegetation provides a high diversity of microclimates for terrestrial ecosystems

Answer 71

Weather, climate

Answer 72

Global, regional, local, micro

Answer 73

Salinity and depth

Answer 74

1) climate 2) type of parent material 3) topography 4) aspect 5) vegetation

Answer 75

how an individual responds to its abiotic environment | Emphasis on responses of animals to fluctuations in temperature

Answer 76

- Many temporal scales: daily, seasonally, annually | - Variation may be predictable (Sun rises and sets) or unpredictable (tornado)

Answer 77

Fitness depends on an individual’s ability to cope with environmental change

Answer 78

- an individual’s response to these changes must be shorter than the period of change - Ex) lungfish adapted to live without water for a certain period of time during dry periods

Answer 79

1) Developmental 2) Acclimatory 3) Regulatory

Answer 80

-takes years and irreversible -Individual alters its development to produce a phenotype most suitable to a persistent slow change in environmental conditions -E.g. Wing length in European freshwater Water Striders (genus Gerris § inhabiting temporary ponds (can dry up periodically year to year) § Eggs hatch (spring) § Adult lifespan is short (reproduce & die during one summer) § 2 morphs (2 discrete phenotypes): A) *If high temperature during egg development, long-winged can fly, move if pond dries up, but more energy into survival than reproduction B) Short-winged cannot fly, cannot move if pond dries up but more energy into reproduction than survival = MORE FIT since produce more offspring

Answer 81

-takes days/weeks and is reversible -changes in response to seasonal variations -e.g. thickening of fur for winter; frost hardening in plants and wood frog -habituation of an organism’s physiological response to environmental conditions -Tolerances are not fixed but are preconditioned by the recent experience with environmental conditions § e.g. Insect - “freeze avoidance strategy” □ Avoid freezing instead of tolerating it □ As temperature starts to decrease in the fall, alcohol peaks and glycogen depletes □ Alcohol has a lower freezing point □ Convert glycogen reserves into alcohol □ Alcohol depresses the freezing point of the body=freeze avoidance

Answer 82

Acclimation – applied to laboratory | Acclimatization – applied to nature

Answer 83

- takes seconds/minutes and is reversible - Rapid changes in behaviour or rates of physiological processes - e.g. shivering in animals; open/close stomata in plants - Short time scale response

Answer 84

a. Conformers – allow internal conditions to follow (match) external changes b. Regulators – maintain constant internal conditions

Answer 85

- ability to maintain constant internal conditions in a varying environment - Always involves a negative feedback system - Eg) thermostat: too hot=turns off, too cold=turns on i. mechanism that senses the internal condition ii. means of comparing the actual with the desired internal condition iii. apparatus that alters the internal condition in preferred direction

Answer 86

A) Poikilothermy (Conforming) -cannot maintain constant body temperature (body temp varies) -Most amphibians, fish and insects -Only active in a narrow range of temperatures B) Homeothermy (Regulating) -maintain constant body temperature -most birds and mammals ~ 36 – 41 degrees C (temp. at which biochemical processes within cells are efficient) -Highly active under varying temperatures

Answer 87

Ectotherms - regulate body temperature by gaining heat from external sources (Most are Poikilotherm) Example) Deep sea fish: Ectothermic Homeotherm Endotherms - regulate body temperature by the production of heat (metabolism) (Most are Homeotherm) Example) Naked Mole Rat: Endothermic Poikilotherm, internal temperature is variable with the temperature of their burrow (environment) but they are mammals so can produce their own heat

Answer 88

Ectotherms: Adv. - energy expenditure can be low Disadv. – growth, reproduction and survival is limited by temperature fluctuations; Active only in a narrow range of temps Endotherms: Adv. – growth, reproduction & survival is not as affected by temperature fluctuations; Constant performance of biochemical reactions at a range of environmental temperatures; Active at a wide range of temperatures Disadv. - energy expenditure must be is high to maintain metabolic heat production

Answer 89

Ectotherms: - must behaviourally generate heat (when active) - Every aspect of ecology and behaviour is influenced by the need to regulate body temperature - Ex) digestion in fish is strongly influenced by water temperature: move to warmer water to increase body heat - Ex) iguanas bask in the sun in order to have enough energy to forage for more food Endotherms: -ability to maintain constant body temperature is limited under low temperatures ○ Short-term – by physiological capacity to generate heat ○ Long-term – by ability to gather food (or energy) to satisfy requirements for metabolic heat production -animals usually starve to death before they die of direct causes of cold temperature

Answer 90

1. Lower the regulated temperature of a portion of their body E.g. Birds – legs & feet use Counter-current heat exchange:heat loss is minimized by reducing the temperature gradient between leg and environment 2. Lower the regulated temperature at certain times of the day (Torpor and hibernation) Eg. Hummingbirds Are inactive at low temps: body temperature is regulated around a lower temp, reduces heat loss to environment otherwise would starve to death!Fifty percent less energy consumed when at rest. 3. Become larger - body size is one of the most important animal characteristics - body size dictates the morphology, ecology, physiology and evolution of an organism - the importance of body size in energy conservation lies in the surface area to volume ratio = Allometry

Answer 91

Torpor: temporary reduction in metabolic activity and lowered body temperature Hibernation: extended reduction in metabolic activity and lowered body temperature (e.g. over the winter)

Answer 92

Surface area to volume area of body size

Answer 93

-a relative increase in a physical or physiological property of an organism in relation to its body size • As body size increases, Volume increases faster than Surface Area • As body size changes, Surface Area/Volume ratio changes • As Surface Area/Volume ratio changes, Heat loss to environment changes

Answer 94

-Body heat is produced through metabolic processes (endotherms) -The larger the Volume, the greater the total amount of heat required to keep warm ... but less heat is lost through the outer surface of the organism -Consequence for Small Organisms: § High Surface Area/Volume § Require less heat but hard to keep warm! -Consequence for Large Organisms: § Low Surface Area/Volume § Require more heat but it is retained easier ENDOTHERMIC ANIMALS MUST REACH CRITICAL SIZE: HEAT GENERATION>HEAT LOSS

Answer 95

Developmental, acclimatory, or regulatory

Answer 96

Homeotherm | Poikilotherm

Answer 97

Ectotherm | Endotherm

Answer 98

Endothermy Lowering the temperature in part of their body Lowering their temperature for part of the day Be coming larger

Answer 99

Allometric relationship

Answer 100

Plants are sessile (can’t move around).

Answer 101

1) light 2) temperature 3) water availability

Answer 102

Require initial colonization of plants

Answer 103

process where energy from the sun is used to transform CO2 into carbohydrates (simple sugars) and O2

Answer 104

Photosynthesis takes place in specialized cells (mesophyll cells) in the leaf

Answer 105

Chlorophyll (light absorbing pigment) traps light energy → synthesizes ATP→ this energy drives CO2 → O2 + sugars

Answer 106

- Drives photosynthetic process - Limits amount of photosynthesis the plant can do - A catalyst

Answer 107

- in the mitochondria of cells (plant & animal) | - carbohydrates are broken down to generate energy (ATP), releasing CO2

Answer 108

-Plants both use and produce CO2 and the difference in the rates of these two processes is: -Net Photosynthesis = Photosynthesis – Respiration (= carbon uptake – carbon loss) *can only use as much as they produce

Answer 109

CO2 diffuses into the leaf through openings in the surface of the leaf, called stomata

Answer 110

movement of a substance from areas of higher to lower concentration

Answer 111

CO2 has to be lower in the leaf compared to the environment in order for CO2 to diffuse from the environment into the leaf

Answer 112

As CO2 diffuses into the leaf, water diffuses out of the leaf

Answer 113

A) CO2 enters: atmosphere >> leaf | B) Water leaves: atmosphere << leaf

Answer 114

water lost must be replaced with water taken by roots from the soil

Answer 115

- water - light - CO2 - nutrients

Answer 116

- Leaf tissue - photosynthesis (uptake of CO2) - Stem tissue - structural support (gain access to light) - Root tissue - water and nutrient uptake from the soil

Answer 117

If plant lives in dry area, then they will adapt to have more roots, but less energy for stem and leaf tissues.

Answer 118

Photosynthesis > Respiration (+ carbon balance→ grow) | Photosynthesis > Transpiration (+ water balance→ survive)

Answer 119

- Since they are sessile, must balance adaptations to multiple environmental conditions all at once - adaptations that allow a plant to successfully grow, survive and reproduce under one set of environmental conditions may limit its ability to do equally well under different environmental conditions

Answer 120

- A plant must open stomata to photosynthesize (↑ grow), but it loses water when stomata are open (↓ survival) - Balance between photosynthesis and transpiration and photosynthesis and respiration governs the evolution of terrestrial plants

Answer 121

1. Short time scales: - Regulate opening and closing of stomata during different parts of the day - eg. close stomata during hottest part of the day when highest water loss through evaporation - Leaf curling or wilting reduces the surface area of the leaf exposed to solar radiation and, thus, water loss * Individual, regulatory response

Answer 122

2. Moderate time scales: - Individuals can balance leaf vs root tissue - Wet conditions (ideal) → ↑ leaf tissue & ↓ root and shoot = Increase the photosynthetic surface (maximizes CO2 uptake and photosynthetic rates → growth). No increase in other tissues (ie. shoot, root) because this increases the rate of respiration (CO2 loss). - Dry conditions → ↑ root tissue & ↓ leaf and shoot = Increases the volume of tissue in the soil to extract water. Reduces the surface area of leaf tissue to reduce water loss. * Individual, acclimatory or developmental response

Answer 123

3. Long time scales (evolution): -Species=adaptation -modified forms of photosynthesis to increase water-use efficiency -C4 & CAM plants: additional step in the conversion of CO2 into sugars → higher maximum rate of photosynthesis, higher rate of photosynthesis requires stomata to be open less time - so less water is lost -leaf morphology adaptations to dry conditions: □ smaller and thicker leaves (water storage) □ Smaller stomata □ cover leaves in wax, resin, little hairs (eg. cactus)

Answer 124

1) shade tolerant = low light | 2) shade intolerant = high light

Answer 125

In shade: photosynthesis is limited by availability of light, not the amount of photosynthetic tissue

Answer 126

-lower production of rubisco in leaf tissue (do not expend energy producing high amounts of rubisco) → Lower maximum photosynthetic rate

Answer 127

Compensate by: – higher production of chlorophyll – higher leaf surface area – higher growth of leaves than roots (increases the photosynthetic surface area to offset the decrease in photosynthetic rate, due to lower rubisco)

Answer 128

Consequence: Shade-intolerant - high growth rates under sunlight, but low rates in shade Shade-tolerant - grow similarly under sunlight and shade cannot increase growth dramatically in sunlight because limited by rates of photosynthesis (concentration of rubisco)

Answer 129

- Individual, developmental response - Tree Top (direct sunlight): smaller, thicker leaves → reduces water loss in direct sunlight - Tree bottom (shade): larger, thinner → increases photosynthetic rate in shade

Answer 130

- Response of plants when temperatures drop to below freezing. - If temperatures drop slowly… 1) Ice formation in the cells of leaves 2) Cells dehydrate (can be reversed when temperature rises) - If rapid drop in temperature… 1) ice crystals form within the cell without dehydration 2) can puncture cell membranes and cell contents spill out during thaw

Answer 131

- genetically controlled characteristic - Form protective compounds that act as antifreeze (sugars): lower the temperature at which freezing occurs an require a considerable amount of energy and nutrients - eg. needle-leaf evergreen species: Avoid these costs by shedding leaves * individual, acclimatory response

Answer 132

- during high temperatures, small light coloured hairs that line a leaf’s surface and reflect sunlight - Less heat obtained from solar radiation - Also creates a insulation boundary later

Answer 133

Skunk cabbage - Metabolically generates heat in the spring to thaw snow and attract pollinators - Endothermic plant

Answer 134

Photosynthesis>Respiration | Photosynthesis>Transpiration

Answer 135

Alter timing of stomata opening Root/leaf growth Leaf morphology

Answer 136

Shade-tolerant | Shade-intolerant

Answer 137

- supercooling - frost hardening - deciduous

Answer 138

increases our understanding of how biotic factors influence distribution/abundance of organisms

Answer 139

depends on an individual’s ability to grow, survive, & reproduce

Answer 140

i. Suitable environmental conditions (abiotic factors) ii. Sufficient resources - Acquire appropriate quantities of energy - Acquire energy efficiently (gain > loss)

Answer 141

An individual of one species (predator) consumes all or part of a living individual of another species (prey).

Answer 142

Does not include scavengers or decomposers (what they consume is already dead) Does include herbivores and blood feeders (Mosquitos are predators of humans)

Answer 143

a. Herbivory – prey is a plant or alga b. Carnivory – prey is an animal, predator is typically also an animal - Except the Venous fly trap = carnivorous plant c. Parasitism – for those parasites the feed on host tissues - Ticks feed on blood - Tapeworm is not

Answer 144

the relationship between prey density and predator consumption rate

Answer 145

Consumption rate depends on: a. prey abundance per unit area - (prey density) – all prey species b. search efficiency for prey - (search time, s) c. time to pursue, subdue & ingest prey - (handling time, h)

Answer 146

1. Type I (Rarely observed) *linear graph - search time varies with prey density - handling time is constant but near zero - Eg. passive predators (spiders, filter feeders, herbivores) - occurs if prey densities do not become high enough for satiation - As prey density increases, encounter rates increase, search time decreases - Consumption rates do not level off - *s>h 2. Type II (Most common) *graph increases fast and plateaus - search time varies with prey density - handling time is constant - Predator consumption rate levels off at high prey densities - As prey density increases, search time decreases because easier to find prey (s >> h) - As prey density increases *2, search time is zero but handling remains constant (h >> s) * h>s 3. Type III (Rarely observed) *graph starts to slowly increase, then increases rapidly, then plateaus = exponential - search time and handling time vary with prey density - Predator consumption rate is lower at low prey densities - At low prey density, search time ↑ and handling time ↑ (=pursue, subdue & ingest prey)

Answer 147

- not enough prey encounters to learn high capture efficiency - prey switching - switch to a more abundant prey type - high availability of cover for prey (refuge) at low densities

Answer 148

Specialist – an individual takes one or a few prey types | Generalist – an individual takes many prey types (4 or more)

Answer 149

proportion of a prey type in the diet is higher than in the environment

Answer 150

Preferences will depend on: -Energy content of prey -Nutritional content of prey (eg. vitamins, minerals) Preferences can be switched: -Switch may depend on the abundance of different prey types

Answer 151

- predict the optimal (or best) foraging strategy under certain conditions - Based on mathematical models derived from economics - offers a powerful way to understand foraging decisions of predators

Answer 152

- Foraging behaviour enhances fitness (ie. a foraging strategy = a behavioural trait favoured by natural selection in the past) - Animals maximize net energy gain (ensures high fitness) - Predators must expend energy to obtain prey 1) Energy loss: searching & handling time 2) Energy gain: consumption

Answer 153

Depends on: energy gain - energy loss (= net energy)

Answer 154

Specialist – energy lost searching ~ consume more profitable prey Generalist – consume less profitable prey ~ low energy searching Strategies have similar net energy gain under different environmental conditions... predators switch between these two strategies depending on conditions

Answer 155

Better to be a generalist if low amount of profitable prey.

Answer 156

pursue prey type i when: net energy of prey type i > of current diet ignore prey type i when: net energy of current diet > of prey type i

Answer 157

If Searching time >> Handling time → Generalists - A predator should consume all prey types when overall prey abundance is low - Predators should be generalists in an unproductive environment - Ex) raccoon, eat garbage

Answer 158

If Handling time >> Searching time → Specialists - Eg. Lions - Live in constant sight of prey - Searching is negligible - Handling is time-consuming - Expect lions to be specialists and only take the highest quality prey

Answer 159

- Predators know everything about their foraging environment - Predators perform complex mathematics to determine the profitabilities of a variety of prey types - We should not expect a perfect match!

Answer 160

—Model predicts: Individuals that approach the optimal strategy will have higher fitness - Predators may use “general rules” - Eg. take the less profitable prey type after searching for a fixed amount of time - Predators may not maximize net energy gain - Eg. take a less profitable prey type with a specific dietary requirement (nutrient, vitamin) - Predators may minimize their own risk of predation - Eg. take a less profitable prey type to avoid foraging near a predator

Answer 161

Local prey density

Answer 162

Functional response Type 1,2,3 *know how these forms differ an be able to draw graphs

Answer 163

Optimal | Natural selection

Answer 164

Gain Loss Profitability

Answer 165

Preference

Answer 166

When demand for resources exceeds the supply

Answer 167

an interaction between individuals of the same species (intra) brought about by a shared requirement for a resource in limited supply

Answer 168

Results in: - Reduced survival, growth, and/or reproduction of some individuals - possible reduction in fitness - Competition acts as a selective pressure in nature

Answer 169

-Resources are not evenly distributed (distributed in patches)= environmental heterogeneity

Answer 170

predators concentrate where prey density is high due to high consumption rates = functional response

Answer 171

1. Exploitation (Scramble) Competition - an individual responds to a decreased level of a limited resource remaining after it has been exploited by other individuals - individuals do not interact directly - Commonly seen in herbivores (bisons graze) 2. Interference (Contest) Competition - an individual actually prevents another from exploiting a limited resource within a portion of the habitat - individuals interact directly - Fighting over food, breeding grounds, water, mates

Answer 172

1) survival 2) reproduction 3) growth

Answer 173

- Decrease net energy gain = energy loss ↑ +/or energy gain ↓ due to competitive interactions - Low competition → Reduced Growth - Moderate competition → Reduced Growth, Reproduction - High competition → Reduced Growth, Reproduction & survival - Consumption rates decrease with increasing numbers of competitors (density-dependent)

Answer 174

-Use Behavioural Ecology to study how an individual’s behaviour is adapted to it’s environment

Answer 175

Model Assumptions: a. There are a number of prey patches that vary in quality (environmental heterogeneity) b. Competitors are ‘free’ to exploit all patches (can move ‘freely’ among patches) c. Individual prey consumption rates decline with increasing numbers of competitors in the patch increases (resources in a patch are limited) d. Individuals have equal competitive abilities e. Animals distribute themselves ‘ideally’ among patches to obtain highest consumption rates (maximize net energy gain to ensure high fitness) and Individuals have perfect knowledge of their environment

Answer 176

Ideal Free Distribution (Fretwell and Lucas 1970)

Answer 177

- Individuals will aggregate to the high quality patch first - As competition increases in high quality patch,the patch quality decreases, leading to lower consumption rates - Inividuals move to moderate and then low quality patches - Individuals in an area reach an equilibrium distribution,all patches occupied * At the equilibrium distribution, the consumption rates of individuals are equal for all competitors in all patches - Can be a dynamic equilibrium – individuals are constantly moving among the available patches - but individuals in the lowest quality patch will not gain access to more prey if they move to a higher quality patch

Answer 178

- Prey arrives in the patch at a particular rate - Prey is consumed immediately - Scramble/Exploitation Competition -competitors do not interact directly

Answer 179

- Ducks on a lake with two feeding stations (station A and B) - pre-cut, weighed bread pieces - identify individual ducks - same input rate at A and B - PREDICTED IFD (Ideal Free Distribution): same amount of ducks at each patch

Answer 180

Prey Input Rate: Station A = Station B (29 trials) - total: 33 ducks - Predict ~ 17 ducks per station (pink) - Did a number of trials - After 80 s - distribution stabilized as predicted - error bars suggest variability among trials because it took ducks a while to figure out the change in their environment (pieces of bread) - Graph fluctuates since ducks keep up the competition by going back and forth in each station

Answer 181

-Prey Input Rate: Station Ax2 >> Station B -total: 33 ducks -Predict ~ 11 ducks at station B (pink) -2x as much in A -After 60 s - distribution stabilized as predicted -Observation: ○ Some ducks took a larger proportion of the food ○ ducks distributed themselves as predicted but two phenotypes: good vs poor competitors Problem: ○ ducks violated the assumption of equal competitive ability

Answer 182

Solution: - modify IFD: assume an individual’s prey consumption rate is proportional to it’s competitive ability - so do not expect no. of individuals to be equal at A and B when prey input rate at A=B - if ‘good’ takes 2x prey of ‘poor’... (1 ‘good’ ind= 2 ‘poor’ inds) - (2)x2 +1+1+1+1+1=9 prey consumed – 7 individuals - (2)x3 +1+1+1=9 prey consumed – 6 individuals - So you would have equal prey consumption at each patch but not necessarily an equal number of competitors (or equal consumption rates of each predator)

Answer 183

Intraspecific Exploitation Interference

Answer 184

Aggregative response | Ideal free distribution

Answer 185

Prey | Competitor

Answer 186

- Resources are often limited so organisms must decide how to allocate time/energy to different activities throughout lifespan - allocation decisions will affect an individual’s fitness by influencing growth, reproduction and survival - Therefore, organisms will develop allocation strategies over evolutionary time to adapt to abiotic and biotic conditions in their environment

Answer 187

* increased allocation of time/energy to some activities results in a decreased allocation to other activities * increase in one thing means a decrease in something else

Answer 188

Growth and survival VS reproduction

Answer 189

the proportion of available resources that an individual allocates to reproduction throughout its lifespan = current + future reproductive output

Answer 190

survival + fecundity in the future

Answer 191

number of offspring produced/event

Answer 192

- the number of offspring produced throughout the lifespan of an individual - similar to fitness... but not does not involve the offspring surviving to reproductive age

Answer 193

set of choices and decisions resulting in an individual’s allocation to reproductive effort through its lifespan

Answer 194

1. Invest heavily in current reproduction - may drain a parent’s energy reserves - reduce parent’s ability to grow → lower probability of survival - If parent survives, may produce fewer offspring in the future 2. Invest heavily in current growth/survival (delay reproduction) - faster growth → higher probability of survival - larger size – more resources available for future reproduction

Answer 195

*The optimal strategy will be a compromise between the allocation of time/energy to growth/survival versus reproduction...

Answer 196

1. Body size / growth (General pattern: fecundity increases with body size) 2. Age at sexual maturity 3. Number of reproductive events (parity) 4. Number of offspring produced per event (fecundity) 5. Offspring size 6. Amount of parental care 7. Senescence, programmed death (termination of life) ○ Limited resources, less and less for each generation ○ Decreasing fitness of population if not removing older individuals due to not producing viable offspring

Answer 197

- A life history strategy integrates all of these traits in a way that maximizes fitness because the strategy influences an individual’s fitness - the strategy will be molded by natural selection over evolutionary time - Which strategy evolves depends on environmental conditions…

Answer 198

answers express each species (individual’s) trade-off between reproduction and adult growth/survival

Answer 199

a. Semelparity – reproduce once and die | b. Iteroparity – reproduce repeatedly throughout life span

Answer 200

- General pattern: semelparity occurs more for organisms living under variable environmental conditions - Therefore, semelparity is favoured when: - Adult survival is low (lifespan < 1-2 years) - Or adult survival is high, but long intervals between years with conditions suitable for high offspring survival * Organisms store resources and reproduce when conditions are favourable and most offspring are likely to survive (Carpe diem! Seize the day)

Answer 201

- Adult life is short lived lasting hours to a couple of days - Do not consume food as an adult - Sole purpose is reproduction - After copulation the female will go off to lay her eggs and die - The male just goes off to die - Semelparous insect=short live

Answer 202

- inhabit climates with erratic rainfall - plants store nutrients and grow for several years (average life span ~ 25 years) - Reproduce during an unusually wet year - Seeds have a higher chance of establishment/survival - Parent plant diets after flowering (reproduction) - Semelparous plant=long lived

Answer 203

- Semelparous not only under variable environmental conditions, but when parents are not likely to survive breeding - Fish grow rapidly at sea for several years - Huge effort to migrate up rivers to reach spawning grounds (>150 km!) - during spawning migration, females convert a large portion of body tissue into eggs - Reproduce and die shortly after spawning = Semelparous fish

Answer 204

- Male are semelparous - Females are iteroparous - This is largely due to the tendency of the female to eat the male before they have a chance to reproduce with another female - Extra nutrients from male means there are more resources for the female to devote to her offspring = fitness for subsequent generations, not for the individual

Answer 205

If iteroparous… - General pattern: as more offspring are produced, the survival of each offspring decreases - Fewer offspring → allocate more resources per offspring - More offspring → allocate less resources per offspring

Answer 206

Whales have 1 calf every 2-3 years vs sunfish have millions of eggs per year 10 coconuts per year vs millions of seeds of the dandelions

Answer 207

- Iteroparous bird - Most frequent = 9 eggs/clutch (less survive) - More offspring survive from a 12 egg/clutch - Why would parents produce less young than they are capable of doing? - Large clutch may drain a parent’s resources: - reduce adult survival → fewer total offspring production over lifespan (LRS) - Produce more offspring over lifespan if produce a lower than maximum number of offspring in a given year...

Answer 208

- General pattern: Age of maturity increases as adult lifespan or annual survival rate increases - Remember... General pattern: fecundity increases with body size (Growth is important!) - Long lifespan (high annual survival rate): - current fecundity should not jeopardize future growth, survival and reproduction - favour growth in 1st few years to increase fecundity - favour reproduction over lifespan (~ breed older) - Short lifespan (low annual survival rate): - current fecundity at the expense of adult survival (especially if semelparous) - do not favour growth, may die before breeding - favour current reproduction (~ breed younger)

Answer 209

- Low annual survival – breed younger - High annual survival – breed older, but do not delay too long! - Since most organisms experience senescence = gradual increase in mortality and decline in fecundity with age

Answer 210

gradual increase in mortality and decline in fecundity with age

Answer 211

different life history strategies are favoured under varying abundances of resources

Answer 212

1. If resources are unlimited (abundant) - Low competition among individuals within a population - Population growth (“intrinsic rate of increase”, r) is at its maximum - adaptations will enhance (selection will favour) rapid population growth - Reproduction >> Growth/Survival = r-selected 2. If resources are limited - High competition among individuals within a population - Population growth is low - population is at “Carrying Capacity”, K - adaptations will enhance (selection will favour) competitive ability - Growth/Survival >> Reproduction = K-selected

Answer 213

R-small | K-large

Answer 214

R-early | K-late

Answer 215

R-Semelparous | K-Iteroparous

Answer 216

R-small | K-large

Answer 217

R-many | K-few

Answer 218

R- low | K- high

Answer 219

R- large reproductive allocation but invest little in survival K- large allocation to survival but little in reproduction

Answer 220

No, strategies fall along a continuous spectrum between r an k selection both within and among species

Answer 221

Life history Trade-offs Growth/survival reproduction

Answer 222

``` Semelparous Iteroparous Current Future Annual survival rate ```

Answer 223

R-selected or k-selected | Selection pressures

Midterm 1 (Lectures 1-9) Flashcards

(255 cards)