Exam 3

What is plasticity?

“In a broad sense, plasticity refers to adaptation in real time: the various adjustments that an individual can make within a single lifespan.”

How is plasticity different from adaption in the evolutionary sense?

Adaption over a single lifespan rather than beyond that with evolution.

What is omnivory?

Dietary habit of organisms that consume both plant and animal matter, allowing them to adapt to various environments

Intersexual Selection

Males demonstrate quality to females; females choose

What does male-male competition to determine mating imply?

Social hierarchy, fighting, and territoriality of harem and resources

What is hybridization?

the interbreeding of distinct populations, subspecies, or species, creating offspring with mixed ancestry

Predator- Prey Cycles

Populations oscillate. Out of phase, but regular

Top-down vs. Bottom-up control of populations refer to

trophic levels in a food chain

Top-down control

Consumers at top of food chain (predators) control size of populations lower in food chain

Bottom-up control

Resources at base of food chain control size of consumer populations

Top-down control can lead to

Trophic cascades, an indirect top-down effect that benefits food of prey

Under top-down control, can predators control prey populations?

An example is how lions preyed one young, old, and ill. Which influenced wildebeest populations more influences by forage and rainfall.

What is predator-mediated coexistence?

an ecological mechanism where a predator prevents a dominant prey species from competitively excluding inferior competitors, thereby maintaining higher biodiversity.

What is a trophic cascades

An ecological phenomenon where adding or removing top predators causes powerful, indirect ripple effects down the food chain, altering ecosystem structure

What does it mean if a predator is a keystone species

The predator has disproportionately large impact on its ecosystem relative to its low populations size, holding the entire ecosystem structure together

Terrestrial

N-facing slopes, deep narrow ravines, talus slopes, ice caves

Aquatic

deep water (marine, lakes), upwelling ocean currents, headwater streams, groundwater springs in lakes and rivers

Salinity at surface is high due to

evaporation

Why do invasive species often compete with native species?

Broad ecological niches, r selected growth rate, expand range quickly, fewer limitations (ecological release), successful invaders

Invasive species are an even bigger problem for islands because of

-High endemism

-Limited areas

-Small population size

-Island ecosystems often lack mammalian predators

-Simpler species interaction (ecosystem can lose its balance easily)

What kind of trout was an issue in Flathead Lake, Montana

Lake trout

What is an invasivore

A person who deliberately eats invasive species

The predator-prey theory is a

Biological and mathematical concept explaining how predator and prey populations influence each other's size in cycles

The flow of energy in ecosystem ecology is a

One-way flow

There is a ____ of nutrients between parts of the biosphere

Cycling

The levels of organization in nature

Atom → Molecule → Cell → Organism → Population → Community → Ecosystem → Biosphere

Natural Capital Degradation

Building roads into previously inaccessible forests

What is the extent of tropical deforestation in percentage

64%

Fragmentologist

Researchers specializing in the study of biological fragmentation

Fragmentation in biology is

A form of asexual reproduction where an organism breaks into smaller pieces, or fragments, with each fragment developing into a new, genetically identical adult.

Refugee effect

A phenomenon in ecology and population genetics where individuals from a destroyed or disturbed habitat (“refugees”) flee to other, often marginal, habitats to survive

What is ecological relaxation

The process of species loss from an ecosystem following a disturbance that reduces its capacity to support biodiversity, such as habitat fragmentation or isolation

What are anthromes

The terrestrial biosphere's modern, human-altered ecosystems, characterized by sustained, direct human interaction rather than just climate

What are wildlands

Terrestrial or aquatic areas that are not significantly modified by human activity, where natural ecological processes are allowed to proceed with minimal human interference

What is extinction debt

The future, delayed extinction of species caused by past environmental changes, such as habitat loss or fragmentation

What are ecological corridors

Linear, managed landscape features (like forests, rivers, or hedgerows) that connect isolated habitat patches, allowing wildlife to move, migrate, and maintain genetic diversity

How do ecological conditions and biodiversity of “islands” created by fragmentation compare to those of true islands?

They differ significantly in their ecological dynamics, primarily because fragments are recently isolated, surrounded by a "matrix" of human-altered land, and subject to intense, rapid environmental changes that are often more devastating than those on true islands

How does habitat fragmentation interact with climate change impacts?

This interaction increases extinction risks, disrupts connectivity, and reduces ecosystem resilience to extreme events like fires and droughts

The larger the island then the

Higher the diversity

Species-area equation

S = cA^z

S = richness

c = constant

A = island area

z = slope relating S and A

In general, diversity doubles for every

10-fold increase in area

In order to predict species loss due to loss of habitat area we use

A in the species-area equation

What are other conditions that affect the eventual response of habitats to fragmentation

matrix quality, edge effects, patch isolation, and temporal changes. The surrounding land use (matrix), such as urban sprawl or agriculture, dictates movement permeability, while edge effects create microclimatic changes (wind, light) that alter interior conditions

Equilibrium Model (MacArthur and Wilson 1963)

Balance of immigration of new species and extinction of species determines diversity on islands

Species richness is related to

Remoteness (immigration potential) and size (extinction risk) of the island

How can island biogeography be applied to the current extinction crisis?

Habitat fragmentation and biodiveristy

The goal of reserve design is to

Maximize diversity by maintaining integrity of habitats

“SLOSS” debate

Single large reserve or several small reserves that are connected

Single large reserve

Pros: better for animals overall, high biodiversity, untouched and don’t need to maintain

Cons: political implications, more costly, not many different habitats

Several small reserves

Pros: better in a city/urban area, cheaper, library of habitats

Cons: need to be connected, less overall biodiversity

Elements of reserve design

Maximize size of protected areas, connect the protected areas with wildlife corridors, buffer conservation areas from adjacent heavily used areas

An example of the goal of reserve design being accomplished is

Costa Rica’s 8 megareserves to preserve biodiversity (National parkland surrounded by buffer zones)

How can we preserve biodiversity?

Designate protected areas, create wildlife corridors that ensure gene flow, and resource access under metapopulation model

A metapopulation model is

A conceptual and mathematical framework (often representing "populations of populations") that analyzes how patchy habitats, separated by unsuitable areas, interact through colonization and extinction

What are the components of community structure

1. Mix of species found in a community

2. Abundance (relative, importance)

3. Distribution of individuals among species

The fundamental question of community ecology

Whether biological communities have tightly prescribes organization and composition, or if they merely loose assemblages of species

What factors determine biological structure and diversity of communities

Climate, topography (biomes), biological interactions, (competition, predation) disturbance and time

Jenkins and Bukema experiment (1998)

12 identical ponds with no preexisting organisms, examined water samples from each pond over time and identified the plankton species present in each sample. Found that species have evidence of predictability and stochasticity

Ecological succession

Changes in community structure over time

-Affects all species in a community “community assembly”

What is community assembly

The study of the processes that determine which species arrive, persist, and interact to form ecological communities

Primary succession

Developmental sequence of communities on abiotic medium, terrain that never had life on it before (ex. lave)

Secondary succession

Developmental sequence of communities on previously vegetated soil, can start with an area that had a mild fire (ex. Yellowstone’s fire adapted species)

What is the relationship between succession and diversity?

Initially, diversity increase during succession but later diversity declines due to biotic interactions like competition

Intermediate disturbance hypothesis (Connell 1978)

Disturbances can reduce competition by limiting size of populations, enable coexistence

Shannon diversity index

Measures the species richness and evenness in a community

Population

Group of individuals of the same species that live in the same area

Communities

Different populations that live together in a defined area

Resistance

Ability of a living system to “resist” moderate disturbance (ex. tropical forests are resistant to hurricanes by recolonizing)

Resilience

Ability of a living system to recover from disturbance (ex. tree sprouting from their stumps, steam)

System with no resistance or resilience

Alpine tundra

Resistance and resilience determine

Stability

Examples of how some systems have one property but not the other

Tropical wet forests have high resilience, and streams have high resistance

Metapopulations

Groups of populations consisting of small subpopulations of the same species that occupy distinct habitat patches

The overall population size of metapopulation stays relatively stable when there is

A sufficient migration rate among populations

Although some subpopulations go extinct over time

Migration can restore or establish subpopulations

Under metapopulation theory, are all populations in a metapopulation expected to go extinct at some point in time

Yes, that is true

Metapopulation Dynamics Implications for conservation of endangered species

The core implication is that long-term survival of an endangered species often depends on maintaining a network of habitats, rather than focusing solely on protecting a single, isolated population.

HLPS Ch. 5 “Global weirding”

Clear predictions of where species are going but no predictions of what will happen when they get there

HLPS Ch.7 “Adaptive movement

Shiftiness

HLPS Ch. 5 & 7

30,000 documented climate-driven range shifts (likely 25A%-85A% of ALL species will shift ranges). Which will be the greatest redistribution since the last ice age

What is ecological naviety

The failure of native prey to recognize or properly respond to novel predators (or competitors) because they lack evolutionary experience with them

California coast in Ch.5 and Tasmania in Ch. 7

Topicalization of cold ocean areas

What percentage of tree species shifted between 1980 and 2015

75%

Pros to plasticity

Rapid adaptation to fluctuating environments, enhanced survival against predators, and increased reproductive success.

Cons of plasticity

Direct metabolic costs, the risk of producing a maladaptive phenotype due to inaccurate environmental cues, and developmental instability.

What are some ways “plasticity” is shown by organisms?

Organisms alter their body shape, size, or structure to better fit their environment

Outcomes of plasticity in populations

Allows populations to survive rapid environmental changes, increases colonization success, and aids adaptation to novel habitats

An animals that exhibits plasticity

Bears adjust their physiology, behavior, and body composition in response to environmental changes and food availability -they exhibit plasticity through varied denning times, adaptable diets, and changing body size based on regional conditions

Omnivory & energetics of grizzly bears on Kodiak Island

Life history – 5 to 7-month hibernation (do not eat, drink, urinate, or defecate; metabolism slows by ~50%; live off fat layer, lose ~25% of their body weight), hyperphagia to build fat stores (~30,000 calories/day, “Fat Bear Week”)

What are benefits of omnivory in the face of climate change

Ability to adaptively switch food sources based on availability, providing high dietary flexibility and increased resilience against food scarcity caused by environmental disruptions

Humbolt squid in Gulf of California

“Disappeared” after water warmed - became smaller in size due to having to eat smaller food

HLPS Ch.9 Evolve

Climate change might modify mechanisms of natural selection, and in response to climate change population’s traits may change

Arboreal lizards (anoles)

Became more wind -resistant by hanging onto the trees during tropical storms

Brown tree snakes

Introduced to Guam, caused native bird extinctions and power outages

Keystone species

A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically

Wooly adelgid

Species that is good with warm winters and destroy Hemlocks

Autotrophs

Organisms that make their own food, photosynthetic organisms

Carnivores

2º consumers that eat meat (ex. lion)

Eurosta Gal Midges

Small flies that do better with colder winters and seek refuge in golden rod plants

Food chain

Movement of energy and nutrients from one trophic level to the next