Bio Modual 3

What Determines Where Species Live?

• Where they can ________ and _________

• Ecological niche (“Nitch”)

  • Range of abiotic conditions they can (tolerate/persist)

  • Range of biotic conditions they can (tolerate/persist) in

  • The abiotic and biotic factors can interact

What Determines Where Species Live?

• Where they can survive and reproduce

• Ecological niche (“Nitch”)

  • Range of abiotic conditions they can tolerate

  • Range of biotic conditions they can persist in

  • The abiotic and biotic factors can interact

Biotic Factors

• Examples: ____________________________________

  • Working in combination with abiotic factors

• ______ Niche: Actual range (where they occur in real life)

• ______ Niche: Potential range (where they could exist based on abiotic factors)

  • Biotic factors create ________

• Realized niche can be the same as the fundamental niche

Biotic Factors

• Examples: Competition, predation, parasitism, mutualism, dispersal ability

  • Working in combination with abiotic factors

• Realized Niche: Actual range (where they occur in real life)

• Fundamental Niche: Potential range (where they could exist based on abiotic factors)

  • Biotic factors create limitations

• Realized niche can be the same as the fundamental niche

Biogeography: How and why species are _________ the way they are due to history 

• Considers where the _________ used to be, which land masses were _________, who was separated, how long __________ lasted 

  • As land separates, gene flow is ________ and speciation/divergence begins to _________

Biogeography: How and why species are distributed the way they are due to history 

• Considers where the continents used to be, which land masses were connected, who was separated, how long isolation lasted 

  • As land separates, gene flow is eliminated and speciation/divergence begins to occur 

Biogeographic Regions

• Earth’s land mass can be divided into (#) biogeographic regions that differ in species composition and richness

  • Correspond to the major _____ _____

• These regions differ in: Species composition, evolutionary history, and endemism

• When the plates separate: Population becomes isolated and ________ occurs

• When the plates collide: __________ becomes possible and interchange occurs

Biogeographic Regions

• Earth’s land mass can be divided into six biogeographic regions that differ in species composition and richness

  • Correspond to the major tectonic plates

• These regions differ in: Species composition, evolutionary history, and endemism

• When the plates separate: Population becomes isolated and speciation occurs

• When the plates collide: dispersal becomes possible and interchange occurs

The geographical distribution of a given clade will be determined by: (1-3)

1. _____________

2. _____________

3. _____________

4. _____________

5. _____________

Niche Starting Limitations Located Temporally

The geographical distribution of a given clade will be determined by: (1-3)

1. The ancestral ecological niche of the clade

   • (What did they occupy historically? They’re not going to suddenly develop all new features and move to new niches.)

2. The geographical starting point for dispersal

   • (They can’t just disperse anywhere)

3. Limitations to dispersal imposed by abiotic conditions and other species (biotic conditions)

   • (Maybe a species can’t move into a space because of the temperature or an established predator)

4. Opportunities for niche evolution that are afforded to individual species by their geographical location

   • (You can only move into a niche space that exists in the space you’re in)

5. The amount of time since the origin of the clade, during which niche evolution and dispersal could occur

   • (How much time they’ve had to evolve)

Tectonic history of Earth: Pangaea

• Ancient supercontinent (~250 mya)

• No oceanic barriers separating species

• Lead to broad terrestrial dispersal and shared lineages 

TIMELINE

1.Break up of _______ (initiated 180 mya)

• Caused major _______ events (when gene flow stops, divergence begins)

2.Most of _______ separated into lots of different continents (100 mya)

• Ocean barriers formed, isolation increased, and independent evolutionary trajectories emerged

3._______ ~75 mya

• Important temporary land bridge that allowed people to get to North America

4.Land bridges existed between _______ and North America (65 mya)

5.All _______ separated (50 MYA)

• _______ is about to collide with Eurasia (20 cm per year!)

6.Central American land bridge ~3 mya

• The Great American _______ Interchange

• This bridge still exists (_______)

• Caused many marsupials to go extinct bc _______ animals outcompeted them

TIMELINE

1.Break up of Pangaea (initiated 180 mya)

• Caused major vicariance events (when gene flow stops, divergence begins)

2.Most of Gondwanaland separated into lots of different continents (100 mya)

• Ocean barriers formed, isolation increased, and independent evolutionary trajectories emerged

3.Beringia ~75 mya

• Important temporary land bridge that allowed people to get to North America

4.Land bridges existed between Europe and North America (65 mya)

5.All continents separated (50 MYA)

• India is about to collide with Eurasia (20 cm per year!)

6.Central American land bridge ~3 mya

• The Great American Biotic Interchange

• This bridge still exists (Panama)

• Caused many marsupials to go extinct bc placental animals outcompeted them

Example from __________: Modern species of flightless Ratites

• Key:

  • Dotted line: Cretaceous-Tertiary boundary

  • Circle: Loss of flight

  • Grey shaded area: fragmentation of South Gondwana

• Shows there were _____________________________

Example from Gondwanaland: Modern species of flightless Ratites

• Key:

  • Dotted line: Cretaceous-Tertiary boundary

  • Circle: Loss of flight

  • Grey shaded area: fragmentation of South Gondwana

• Shows there were multiple independent origins of flightlessness

The Great American Biotic Interchange

• Modern Marsupial distribution reflects

  • Ancient plate _____________

  • Later _____________ collisions

  • _____________ introductions

• Niche + dispersal + tectonics + time 

The Great American Biotic Interchange

• Modern Marsupial distribution reflects

  • Ancient plate connections

  • Later continental collisions

  • Competitive introductions

• Niche + dispersal + tectonics + time 

• What is Population Ecology: How population _____ changes, why those changes occur, and how populations are _____ in space

• Why is it important?

  • Links _____ and _____

  • Essential for: conservation biology, fisheries management, and understanding human population growth

• Fundamental questions: Where does a species _____ and _____ _____ individuals are there

• What is Population Ecology: How population size changes, why those changes occur, and how populations are distributed in space

• Why is it important?

  • Links ecology and evolution

  • Essential for: conservation biology, fisheries management, and understanding human population growth

• Fundamental questions: Where does a species live and how many individuals are there

________: Number of individuals per unit area

• Varies across a species’ range (________ niche)

Three main spatial distribution patterns

1. Random distribution

   • Ex. ________

2. ________ distribution

   • Associating in social groups

   • (Most/least) common pattern

   • Causes patchy resources

3. _________ distribution

   • Evenly spaced

   • Caused by negative interaction like _________

Density: Number of individuals per unit area

• Varies across a species’ range (realized niche)

Three main spatial distribution patterns

1. Random distribution

   • Ex. dandelion seeds

2. Clumped distribution

   • Associating in social groups

   • Most common pattern

   • Causes patchy resources

3. Uniform distribution

   • Evenly spaced

   • Caused by negative interaction like competition

Metapopulation: A population of __________

• Ex. fragmented prairie with lots of different butterfly populations. If you look at the __________, that’s a metapopulation

• Smaller populations that make up a metapopulation can be connected by __________ and therefore share __________, but they do function as __________ populations

• __________ __________ increases metapopulation structure (creates isolated populations)

• Local __________ can be offset (if one butterfly population dies, individuals from surrounding populations may re-colonize the area)

Metapopulation: A population of populations

• Ex. fragmented prairie with lots of different butterfly populations. If you look at the whole field, that’s a metapopulation

• Smaller populations that make up a metapopulation can be connected by dispersal and therefore share alleles, but they do function as independent populations

• Habitat fragmentation increases metapopulation structure (creates isolated populations)

• Local extinctions can be offset (if one butterfly population dies, individuals from surrounding populations may re-colonize the area)

Measuring Population Size & Distribution for (fast/slow) moving organisms: 

• Quadrat Counting Method: How many individuals are in a ______________________

  • Population = _____________

  • Area: ______

Measuring Population Size & Distribution for slow moving organisms: 

• Quadrat Counting Method: How many individuals are in a predetermined square area (extrapolate out) 

  • Population = Density x Area

  • Area: lw

Measuring Population Size & Distribution for (fast/slow) moving organisms: 

• Line Transects: Have a pre-determined ________ that you follow and count the organisms found there (extrapolate out)

  • Population = ___________

  • Area: ___________

    • “Within 2m of a 100m line” = ___________

  • Density: ___________

    • 40 individuals 

    • ___________

Measuring Population Size & Distribution for slow moving organisms: 

• Line Transects: Have a pre-determined line that you follow and count the organisms found there (extrapolate out)

  • Population = Density x Area

  • Area: 2wl (both sides of the line) 

    • “Within 2m of a 100m line” = 2 x 2 x 100 = 400

  • Density: n/(2wl) 

    • 40 individuals 

    • 40/400 = 0.1 per m^2

Measuring Population Size & Distribution for (fast/slow) moving organisms: 

• Mark-Recapture:

  • Steps: Capture and mark individuals → Release and allow mixing → Recapture and count _____________ individuals

  • Assumptions: _____________, _______________, ______________

Measuring Population Size & Distribution for fast moving organisms: 

• Mark-Recapture:

  • Steps: Capture and mark individuals → Release and allow mixing → Recapture and count marked vs unmarked individuals

  • Assumptions: No immigration/emigration, no trap avoidance or attraction, and marking does not affect survival

Mark-Recapture Math: 

• Mark-Recapture Math: 

  • (Trying to find N)

  • Cross multiply, isolate N (divide), then plug numbers in 

Demography: What determines Population Size

• ____ principals determine population size

  • Increased by: _________ & _________ 

  • Decreased by: _________ & _________ 

• Equation is: ____________________

Demography: What determines Population Size

• BIDE principals determine population size

  • Increased by: Birth & Immigration 

  • Decreased by: Emigration & Mortality 

• Equation is:

Age Structure, Generation Time, & Life Tables

• Age Structure: Number of individuals ________________

• Generation time: Average time between _________ and __________

  • Females are the _______ factor and control population growth more than males 

Age Structure, Generation Time, & Life Tables

• Age Structure: Number of individuals in each age class

• Generation time: Average time between a female’s birth and the birth of her offspring

  • Females are the limiting factor and control population growth more than males 

Life Table

• Shows ____________ and ____________

• Can either take a snapshot of a (longer/shorter) lived species, or measure across the lifetime of a (longer/shorter) lived species

• Limitations

  • ________ is inherently difficult to get

  • Need a _________ population

Life Table

• Shows survivorship and reproduction

• Can either take a snapshot of a longer lived species, or measure across the lifetime of a shorter lived species

• Limitations

  • Data is inherently difficult to get

  • Need a marked population

• Survivorship (__) = Proportion of a cohort that survive to an age class

• Age-specific fecundity (__) = Average number of __________ offspring produced by a female in each age class

• (equation) = Average number of female offspring produced per original female in the population at that age class

• Net reproductive rate (__) = Average female births per year per female

• R₀ < 1 : __________

• R₀ = 1 : __________

• R₀ > 1 : __________

• Survivorship (Lₓ) = Proportion of a cohort that survive to an age class

• Age-specific fecundity (mₓ) = Average number of female offspring produced by a female in each age class

• Lₓ * mₓ = Average number of female offspring produced per original female in the population at that age class

• Net reproductive rate (R₀) = Average female births per year per female

• R₀ < 1 : Decreasing Population

• R₀ = 1 : Stable Population

• R₀ > 1 : Increasing Population

Survivorship Curve (___)

• Type 1: ____________________

• Type 2: ____________________

• Type 3: ____________________

Survivorship Curve (Lₓ)

• Type 1: High initial survivorship with steep decline later (humans)

• Type 2: Steady survivorship (birds)

• Type 3: Low initial survivorship that then levels out (turtles/ants)

Fecundity (__) and Reproductive Rate (__)

• Age specific fecundity often (decreases/decreases) with age

Fecundity (mₓ) and Reproductive Rate (R₀)

• Age specific fecundity often increases with age

Life History & Fitness Trade-Offs

• Trade offs between ________ and __________

  • How many offspring are _________ vs how many __________

• Same species living in different _________ can have different fecundity vs survival rates

• Successful invasive species show ________ life history patterns and adaptation 

Life History & Fitness Trade-Offs

• Trade offs between survivorship and fecundity

  • How many offspring are produced vs how many make it to adulthood

• Same species living in different areas can have different fecundity vs survival rates

• Successful invasive species show diverse life history patterns and adaptation 

Population Growth: Exponential Growth

• Change in population size over time

• Isolated Population: Can be measured by just (equation) (no immigration or emigration)

• Conditions: ________________ & ________________

• Exponential Growth = (equation)

Population Growth: Exponential Growth

• Change in population size over time

• Isolated Population: Can be measured by just birth - death (no immigration or emigration)

• Conditions: Unlimited resources & Constant per-capita growth rate 

• Exponential Growth = (births - deaths) * population size 

Population Growth: Logistic Growth

• Resources are _________

• Growth becomes ________ dependent 

• Carrying capacity = (Letter)

  • Populations either fluctuate around carrying capacity once reaching it or crash

• Equation: ________________

Population Growth: Logistic Growth

• Resources are finite

• Growth becomes density dependent 

• Carrying capacity = K

  • Populations either fluctuate around carrying capacity once reaching it or crash

• Equation: ________________

Density-Dependent vs Density-Independent Factors

• Density-Independent:

  • Affect populations regardless of size

  • Ex. ________, __________

• Density-Dependent

  • Effects that (increase/decrease) with population density

  • Ex. ________, __________, ________, __________

Density-Dependent vs Density-Independent Factors

• Density-Independent:

  • Affect populations regardless of size

  • Ex. Weather, disasters

• Density-Dependent

  • Effects that increase with population density

  • Ex. Competition, disease, predation, waste buildup

Why Do Some Populations Crash?

• Crash: Population declining to _______ or near ________

• This happens when populations overshoot _______ _________

• Overexploitation: __________________________________

  • Ex. Animals overshooting the carrying capacity, overeating the plant life, and lowering the carrying capacity of the environment

Why Do Some Populations Crash?

• Crash: Population declining to extinction or near extinction

• This happens when populations overshoot carrying capacity

• Overexploitation: Environment has degraded due to populations overshooting capacity, and the carrying capacity lowers

  • Ex. Animals overshooting the carrying capacity, overeating the plant life, and lowering the carrying capacity of the environment

Populations Cycles are somewhat ___________

Populations Cycles are somewhat predictable

Competing Hypotheses for Population Cycles

• Bottom Up Hypothesis: _________________________

• Top Down Hypothesis: _________________________ 

• Interaction hypothesis: _________________________

Competing Hypotheses for Population Cycles

• Bottom Up Hypothesis: Hare populations are limited by food, and the lynx will decline when the hares starve (Limited by resources at the bottom of the food web)

• Top Down Hypothesis: Lynx predation controls the hare population size. High predator density causes hare crashes. 

• Interaction hypothesis: Food limits & predation act together and the combined effect is stronger than one alone 

Lotka-Volterra Model Assumptions:

• ______________

• ______________

• ______________

• ______________

Formula: ______________

Lotka-Volterra Model Assumptions: (cels)

• Environment does not change

• Prey grow exponentially without predators

• No resource limitations for prey

• Predators rely on single prey species

Formula:

Metapopulations & Conservation Biology

• Habitat fragmentation creates _______ populations

• Even protected pops. may be too small to _______

• Factors increasing persistence:

  • ___________

  • ___________

  • ___________

  • ___________

Metapopulations & Conservation Biology

• Habitat fragmentation creates isolated populations

• Even protected pops. may be too small to persist

• Factors increasing persistence: (Habitat Diversity Proximity Size)

  • Larger habitat patches 

  • Higher genetic diversity 

  • Proximity to other populations

  • Larger pop. size

• Population Momentum: 

  • Continued growth after ________ declines

  • Caused by a large number individuals reaching ______ ______

• Growth over time

  • We have experienced recent ________ growth

• Population Momentum: 

  • Continued growth after fertility declines

  • Caused by a large number individuals reaching reproductive age 

• Growth over time

  • We have experienced recent exponential growth

What is a community

• Community: Consists of _________________

• Not just which species are present but how they ________

• Biological communities are more than the __________

What is a community

• Community: Consists of all populations of different species interacting in a particular area

• Not just which species are present but how they interact

• Biological communities are more than the sum of their parts

Species Interactions

• ________-based framework

  • Can be positive (+), negative (-), or neutral (0) fitness effects

• Four major interaction types within the framework

  • Commensalism (_____)

  • Competition (_____)

  • Consumption (_____)

  • Mutualism (_____)

Species Interactions

• Fitness-based framework

  • Can be positive (+), negative (-), or neutral (0) fitness effects

• Four major interaction types within the framework

  • Commensalism (+ / 0)

  • Competition (- / -)

  • Consumption (+ / -)

  • Mutualism (+ / +)

• Commensalism (+ / 0)

  • Difficult to study because “________” is hard to quantify 

  • Can change depending on factors like _________

    • Orchids get sun by growing on trees and it doesn’t affect the trees. However, if the orchid population grows a lot, it can weigh down branches or block sun. 

• Commensalism (+ / 0)

  • Difficult to study because “no effect” is hard to quantify 

  • Can change depending on factors like density

    • Orchids get sun by growing on trees and it doesn’t affect the trees. However, if the orchid population grows a lot, it can weigh down branches or block sun. 

Competition (- / -)

• Lowers fitness

  • Growth, survival, reproduction 

• Intraspecific competition

  • (Within/between) species

• Interspecific competition 

  • (Within/between) specific 

• There’s direct and indirect competition

  • Direct- _________________

  • Indirect- _________________

Competition (- / -)

• Lowers fitness

  • Growth, survival, reproduction 

• Intraspecific competition

  • Within species

• Interspecific competition 

  • Between specific 

• There’s direct and indirect competition

  • Direct- physical interference

  • Indirect- depletion of shared resources

Competitive Exclusion

• Competition affects the (realized/fundamental) niche, not necessarily (realized/fundamental)

• Competitive exclusion occurs due to complete ________ overlap

  • (Driving one species to ________) 

Niche Differentiation and Character Displacement

• ________ response to competition

  • Favors individuals that compete (less/more) (use different niche spaces) 

• Trait divergence is often driven by ________

  • Ex. Galapagos Finches

Competitive Exclusion

• Competition affects the realized niche, not necessarily fundamental 

• Competitive exclusion occurs due to complete niche overlap

  • (Driving one species to extinction) 

Niche Differentiation and Character Displacement

• Evolutionary response to competition

  • Favors individuals that compete less (use different niche spaces) 

• Trait divergence is often driven by competition

  • Ex. Galapagos Finches

Consumption Interaction 

• Consumer benefits, victim loses _______

• Three main types

  • _______

  • _______

  • _______

Consumption Interaction 

• Consumer benefits, victim loses fitness

• Three main types

  • Predation (Cheetah & Gazelle) 

  • Herbivory (Kowala & Eucalyptus) 

  • Parasitism (Lice & Humans) 

• Coevolutionary Arms Race: __________________________

  • Ex. Cheetahs and Gazelles are both getting faster

  • Types of Defenses prey species can evolve

    • ______________: Always present 

      • Ex. Thorns on a rose 

    • ______________: Induced w/ response to threat

      • Ex. Plants producing toxic chemicals when being eaten 

• Coevolutionary Arms Race: As a species evolves something that benefits their fitness, the other species will also be evolving to counter them

  • Ex. Cheetahs and Gazelles are both getting faster

  • Types of Defenses prey species can evolve

    • Constitutive defenses: Always present 

      • Ex. Thorns on a rose 

    • Inducible defenses: Induced w/ response to threat

      • Ex. Plants producing toxic chemicals when being eaten 

Parasite - Host Interaction

• Some parasites manipulate host _________

  • Ex. Parasite infects an ant, changing their behavior and making them get eaten by birds who then transmit the parasite to a new location 

• Goal is increasing the _____________ of the parasite 

Parasite - Host Interaction

• Some parasites manipulate host behavior

  • Ex. Parasite infects an ant, changing their behavior and making them get eaten by birds who then transmit the parasite to a new location 

• Goal is increasing the transmission rate of the parasite 

Mutualism (+ / +)

• Both species are experiencing _______ benefits

  • Flowers & Pollinators (Nectar is produced solely as a reward for pollinators) 

  • Clown fish eating sea anemone predators and sea anemone protecting the clown fish 

• Mutualists are not ________

  • Actions are designed to maximize fitness 

• Context dependent: Some of these interactions can turn into (___) interactions under stressful conditions

  • Ex. Coral bleaching

Mutualism (+ / +)

• Both species are experiencing fitness benefits

  • Flowers & Pollinators (Nectar is produced solely as a reward for pollinators) 

  • Clown fish eating sea anemone predators and sea anemone protecting the clown fish 

• Mutualists are not altruistic 

  • Actions are designed to maximize fitness 

• Context dependent: Some of these interactions can turn into (+/-) interactions under stressful conditions

  • Ex. Coral bleaching

Community Structure

• Four key attributes

  • Number of species

  • Relative abundance

  • Network of interactions

  • Physical structure of the environment 

• How to measure community diversity

  • Species richness: Counting the number of species present

  • Species evenness: Relative abundance to each other 

    • Higher evenness → higher diversity (no species dominating) 

  • Species diversity: Richness + Eveness 

Community Structure

• Four key attributes

  • Number of species

  • Relative abundance

  • Network of interactions

  • Physical structure of the environment 

• How to measure community diversity

  • Species richness: Counting the number of species present

  • Species evenness: Relative abundance to each other 

    • Higher evenness → higher diversity (no species dominating) 

  • Species diversity: Richness + Eveness