APES Unit 2 - 3.3 Notes

Specialists

Species with a narrower ecological niche and specific food requirements, making them more prone to extinction.

Generalists

Species with a broader ecological niche and broad food requirements, making them less prone to extinction and more adaptable.

K-selected species

Species that produce few offspring with high parental care, long lifespan, and slow population growth.

r-selected species

Species that produce many offspring with little to no parental care, short lifespan, and high population growth.

Carrying capacity (K)

The maximum population size that an environment can sustain.

Intraspecific competition

Competition among individuals of the same species for resources like food, space, and mates.

Ecosystem diversity

The variety of different habitats available in a given area.

Species diversity

The number of different species in an ecosystem and the balance of their population sizes.

Genetic diversity

The variety of genes within a population, affecting the population's ability to respond to environmental stressors.

Bottleneck event

An environmental disturbance that drastically reduces population size, affecting genetic diversity.

Inbreeding depression

Reduced biological fitness in a population due to inbreeding, leading to harmful genetic mutations.

Ecosystem resilience

The ability of an ecosystem to return to its original state after a disturbance.

Provisioning Services

Goods provided by ecosystems directly to humans for use or sale, such as food and raw materials.

Regulating Services

Benefits provided by ecosystem processes that moderate natural conditions, such as climate and air quality.

Supporting Services

Ecosystem functions supporting processes like nutrient cycling and pollination, which are beneficial for agriculture.

Cultural Services

Non-material benefits people obtain from ecosystems, including recreation and aesthetic enjoyment.

Island Biogeography

The study of ecological relationships and community structure on islands.

Ecological tolerance

The range of conditions an organism can endure before injury or death occurs.

Natural selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Ecological succession

A series of predictable stages of growth that ecosystems undergo, transitioning from one community to another.

Primary succession

Succession that begins on bare rock with no previous soil formation.

Secondary succession

Succession that occurs in areas with established soil after a disturbance.

Type I Survivorship Curve

High survivorship early in life with rapid decrease in later life, typical of K-selected species.

Type III Survivorship Curve

Low survivorship early in life with few surviving to adulthood, typical of r-selected species.

Fitness

The ability of an organism to survive and reproduce in its environment.

Adaptive trait

A new trait that increases an organism's fitness.

Selective pressure

Environmental factors that influence survival and reproduction.

Ecosystem Services

The benefits provided by ecosystems to humans, categorized into provisioning, regulating, supporting, and cultural services.

Species richness

The total number of different species present in an ecosystem.

Species evenness

How evenly individual organisms are distributed among different species in an ecosystem.

Niche

The role or function of an organism or species within an ecosystem.

Ecological niche

The specific environment and interactions of a species, including its habitat, resource use, and behavior.

Biotic potential

The maximum reproductive capacity of an organism under optimal conditions.

Environmental disturbance

A sudden change in environmental conditions that can alter ecosystems and populations.

Climax community

The final, stable community reached after ecological succession.

Microhabitat

A small, specific habitat where specific environmental conditions favor particular organisms.

Adaptation

A characteristic that enhances an organism's ability to survive and reproduce.

Ecological stress

The negative impact on organisms due to changes in environmental conditions.

Diversity-stability hypothesis

The theory that greater biodiversity leads to greater ecosystem stability and resilience.

Carrying capacity

The maximum number of individuals of a species that an environment can sustain over time.

Genetic bottleneck

A sharp reduction in the size of a population due to environmental events, reducing genetic diversity.

Evolutionary pressure

Any environmental condition that affects the survival and reproduction of a species.

Pioneer species

Species that are the first to colonize previously disrupted or damaged ecosystems.

Climatic change

Long-term changes in temperature and weather patterns, influencing ecosystems.

Dispersal

The movement of species from one location to another, which can expand their range.

Mutation

A change in the DNA sequence that can lead to variations in traits.

Hybridization

The process of mating two different species, leading to hybrid offspring.

Ecosystem dynamics

The interactions and changes within ecosystems over time.

Pollinator decline

The decrease in populations of pollinators like bees, which affects plant reproduction.

Co-evolution

The evolution of two or more species interacting with each other, affecting each other's adaptations.

Ecosystem fragmentation

The breaking up of ecosystems into smaller, isolated patches, often due to human activity.

Phenotypic plasticity

The ability of an organism to change its phenotype in response to changes in the environment.

Biophysical interactions

The relationships between biological and physical components in an ecosystem.

Urban ecology

The study of how ecological processes operate in urban environments, including human impacts.

Eutrophication

Nutrient over-enrichment in aquatic systems leading to excessive growth of algae and depletion of oxygen.

Invasive species

Non-native species that spread rapidly in new environments and disrupt ecosystems.

Habitat loss

The destruction or alteration of habitat, leading to decreased biodiversity.

Agroecosystem

An ecological system managed for agricultural production.

Conservation biology

A field of science that focuses on the protection and management of biodiversity.

Photoperiodism

The physiological reaction of organisms to the length of day or night.

Metapopulation

A group of populations that are separated but interact through migration.

Ecosystem health

The state of an ecosystem's structure and function being maintained and resilient.

What are the three levels of biodiversity, and how do they contribute to ecosystem health?

• Genetic diversity: Ensures population adaptability to environmental stressors.

• Species diversity: Indicates ecosystem health through species richness and evenness.

• Ecosystem diversity: Provides varied habitats that support different species and functions.

How does biodiversity enhance ecosystem resilience?

High biodiversity ensures functional redundancy, meaning multiple species can fulfill similar ecological roles, enabling ecosystems to recover from disturbances.

What factors influence biodiversity, and why does latitude play a significant role?

• Latitude: Biodiversity increases near the equator due to warmer climates and consistent energy availability.

• Time: Older ecosystems have higher biodiversity due to prolonged periods of species adaptation and evolution.

• Habitat size: Larger habitats support more species due to greater resource availability and reduced competition.

• Distance from other habitats: Proximity allows for easier species migration and gene flow.

What are the four types of ecosystem services, and provide an example of each?

• Provisioning: Goods like food and water (e.g., fish harvested from oceans).

• Regulating: Services like climate regulation (e.g., forests absorbing CO2).

• Supporting: Fundamental processes (e.g., nutrient cycling in soil).

• Cultural: Benefits for recreation and spirituality (e.g., national parks).

How do human activities such as deforestation and pollution impact ecosystem services?

• Deforestation: Reduces regulating services by increasing carbon emissions and decreasing flood control.

• Pollution: Harms provisioning services by contaminating water sources and reducing crop yields.

Why is nutrient cycling considered a supporting service, and how does it benefit other ecosystem functions?

Nutrient cycling replenishes essential elements like nitrogen and phosphorus in soil and water, supporting plant growth (provisioning service) and stabilizing ecosystems (regulating service).

According to the theory of island biogeography, what two factors determine species richness on islands?

Species richness is influenced by island size (larger islands support more species) and distance from the mainland (closer islands have higher species migration rates).

How does habitat fragmentation mimic the effects of island biogeography?

Habitat fragmentation creates isolated "islands" of habitat, reducing species migration, gene flow, and increasing extinction risks, similar to distant islands

Why do larger islands typically support more species than smaller ones?

Larger islands provide diverse habitats, abundant resources, and can support larger populations, reducing extinction rates.

What are the three zones within an organism's range of tolerance, and how do they affect species survival?

• Optimal range: Conditions for peak survival and reproduction.

• Zone of physiological stress: Suboptimal conditions cause reduced survival and fertility.

• Zone of intolerance: Conditions where the species cannot survive

What are limiting factors, and how do they determine species distribution?

Limiting factors are abiotic elements (e.g., temperature, salinity, pH) that constrain species survival and reproduction, determining where a species can thrive

How might salinity act as a limiting factor for species in freshwater and marine ecosystems?

Freshwater species may be unable to tolerate high salinity, while marine species might die in low-salinity environments, restricting their habitat ranges.

How do natural disruptions like wildfires and hurricanes impact ecosystems in the short and long term?

• Short-term: Destroy habitats and cause immediate loss of biodiversity.

• Long-term: Promote ecological succession and increase biodiversity by creating new niches.

How can species adapt to frequent natural disturbances such as hurricanes?

Species develop physical (e.g., flexible stems), behavioral (e.g., migration), or physiological (e.g., drought resistance) adaptations to survive recurring disturbances.

What distinguishes short-term from long-term effects of volcanic eruptions on ecosystems?

• Short-term: Ashfall destroys habitats and causes species displacement.

• Long-term: Enriches soil with nutrients, supporting succession and new growth.

What are the three types of adaptations, and provide examples of each?

• Physical: Structural changes (e.g., thicker fur for cold climates).

• Behavioral: Changes in actions (e.g., nocturnal behavior to avoid predators).

• Physiological: Internal functions (e.g., salt tolerance in mangroves).

What is the difference between primary and secondary succession?

• Primary succession occurs in lifeless areas (e.g., volcanic lava flows), starting with pioneer species like lichen.

• Secondary succession occurs where soil exists (e.g., after a wildfire) and progresses more rapidly.

Question: Why are pioneer species essential in primary succession?

Pioneer species like moss and lichen break down rock to form soil, enabling subsequent plant species to establish and enrich the habitat.

How do generalist species differ from specialist species in terms of their adaptability to environmental changes?

• Generalists: Can survive in a wide range of conditions and use diverse resources (e.g., raccoons).

• Specialists: Thrive in specific environments and rely on limited resources (e.g., koalas).

Why might specialist species be more vulnerable to habitat loss than generalist species?

Specialists have narrow ecological niches, so they struggle to adapt when their specific habitats or resources are altered or removed.

Provide examples of a generalist and a specialist species and explain how their niches contribute to their survival.

• Generalist: Rats thrive in urban and rural settings by consuming varied diets.

• Specialist: Panda bears depend on bamboo forests, making them vulnerable to habitat destruction.

What are the key differences between K-selected and r-selected species in terms of reproduction and lifespan?

• K-selected species: Few offspring, significant parental care, long lifespan (e.g., elephants).

• r-selected species: Many offspring, minimal parental care, short lifespan (e.g., insects)

How do K-selected species maintain population stability compared to r-selected species?

K-selected species are adapted to stable environments, maintaining populations near the carrying capacity, while r-selected species exploit unpredictable environments by reproducing rapidly.

Why are r-selected species more likely to experience population booms and crashes compared to K-selected species?

r-selected species often overshoot carrying capacity due to high reproductive rates, leading to resource depletion and subsequent crashes.

What are the three types of survivorship curves, and which species are associated with each?

• Type I: High survival in early/mid-life, steep decline in old age (e.g., humans).

• Type II: Constant mortality rate throughout life (e.g., birds).

• Type III: High mortality in early life, with survivors living long lives (e.g., turtles).

Why do Type III survivorship species typically produce many offspring?

• High juvenile mortality rates require producing numerous offspring to ensure that some survive to adulthood.

How do Type I survivorship species’ parental care strategies contribute to their survival?

Type I species invest heavily in their offspring, providing care and resources that improve survival chances into adulthood.

Diversity of life forms in an ecosystem; measured on 3 different levels

• Ecosystem diversity: the number of diff. habitats available in a given area 

• Species diversity: the number of diff. species in an ecosystem and the balance or evenness of the pop. sizes of all species in the ecosystem

• Genetic diversity: how different the genes are of individuals within a population (group of the same species)

• Higher biodiversity = higher ecosystem/population health

Species Richness & Evenness

• Richness (r) is just the total number of different species found in an ecosystem

• Evenness is a measure of how all of the individual organisms in an ecosystem are balanced between the different species 

• High (r) is generally a good sign of ecosystem health (more species means more quality resources like H2O & soil)

• Evenness indicates if there are one or two dominant species, or if pop. sizes are well balanced

Genetic Diversity is Beneficial

• Genetic diversity = measure of how different the genomes (set of genes) are of the individuals within a population of a given species

  • There is genetic diversity in all pops. because random mutations in copying of DNA & recombination of chromosomes in sex cells of parents leads to new gene combinations & new traits in offspring

• The more genetic diversity in a pop. the better the population can respond to env. Stressors like drought, disease, or famine

  • More gen. div. = higher chance that some of the individuals in a pop. have traits that allow them to survive the env. Stressor

Bottleneck Event

• An env. disturbance (natural disaster/human hab. destruction) that drastically reduces pop. size & kills organisms regardless of their genome

  • Surviving pop. is smaller and because individuals died randomly, it doesn’t represent the genetic diversity of the original pop.

• Bottleneck events reduce genetic diversity

  • Because the pop. is smaller & less genetically diverse, it’s even more vulnerable to future env. Disturbances

Inbreeding Depression

• Inbreeding is when organisms mate with closely related “family” members

  • Leads to higher chance of offspring having harmful genetic mutations because they’re getting similar genotypes from both parents

• Smaller populations are more likely to experience inbreeding (difficult to find non-related mate)

  • Ex: Florida panther pop. decreased down to 30 in 1900s due to hunting & hab. loss. Inbreeding depression = kinked tails, heart defects, low sperm count, undescended testicles (saved in 95’ by pumas from Texas)

Ecosystem Resilience

• Resilience = the ability of an ecosystem to return to its original conditions after a major disturbance (wind storm, fire, flood, clear-cutting, etc.)

• Higher species diversity = higher ecosystem resilience

  • High sp. div means more plant species to repopulate disturbed ground, anchor soil, and provide food & habitat for animal specie

Ecosystem Services = $$$

• Goods and services provided by natural ecosystems that are beneficial to humans (often monetarily of life-sustaining)

• Provisioning

  • Goods taken directly from ecosystems or made from nat. resources (wood, paper, food)

• Regulating

  • Nat. ecosystems regulate climate/air quality, reducing storm damage & healthcare costs

• Supporting

  • Nat. ecosystems support processes we do ourselves, making them cheaper & easier(bees pollinate crops)

• Cultural

  • Money generate by recreation (parks, camping, tours) or scientific knowledge

Humans Disrupt Ecosystem Services

• Human activities disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide

  • This has ecological (natural) and economic (money-based) consequences

  • Examples:

    • Clearing land for ag./cities removes trees that store CO2 (more CO2 in atm. = more CC = more storm damage & crop failure)

    • Overfishing leads to fish pop. collapse (lost fishing jobs and lower fish sales in the future)

Provisioning Services

• Goods/products directly provided to humans for sale/use by ecosystems

  • Ex: Fish, hunting animals, lumber (wood for furniture/buildings) naturally grown foods like berries, seeds, wild grains, honey

• Goods/products that are made from natural resources that ecosystems provide 

  • Ex: paper, medicine, rubber

• Disrupted by overharvesting, water pollution, clearing land for ag/urbanization

Regulating Services

• Benefit provided by ecosystem processes that moderate natural conditions like climate and air quality

  • Trees in a forest sequester (store) CO2 through photosynthesis which reduces rate of climate change & lessens damage caused by rising sea level & reduces crop failure from drought 

  • Trees filter air by absorbing air pollutants which reduces health care costs for treating diseases like asthma and bronchitis

    • Disrupted by deforestation

Supporting Services

• Natural ecosystems support processes we do ourselves, making them less costly and easier for us

  • Examples:

    • Wetland plant roots filter pollutants, leading to cleaner groundwater that we don’t have to pay as much to purify with expensive water treatment plants

    • Bees & other insects pollinate our ag. Crops, leading to more crop production & higher profits

      • Disrupted by pollinator hab. loss & filling in wetlands for development