BIOL1030 U3

Sustainability

Meeting the needs of the present without undermining the needs of the future

The three pillars of sustainability

Social, environmental, economic

Populations are _______ in size and structure

Dynamic

Populations

Individuals of species living in the same general area that rely on the same resources, are influenced by similar environmental factors, and likely interact and breed with one another

A species’ abundance and distribution is limited by…

Available resources and interactions between biotic and abiotic factors

We use models to….

Understand, map, and predict the distribution of species and populations

Fundamental Niche

The place where a species or population can theoretically exist - we would expect to see the species here

Realized Niche

Where a species or population actually occupies

We measure populations to…

Understand biology and distribution, reproduction and evolution, and monitor change over time

Biotic and abiotic factors influence characteristics of populations, including…

Density, dispersion, demographics

Density

The number of individuals per unit of area

Dispersion

The spacing between individuals - can be clumped, uniform, or random dispersion

Methods to measure populations may vary because of…

Density and dispersion - accuracy vs precision

Replication in measuring populations

Larger and/or more surveys may be needed for measuring rarer individuals

Scale of measuring

The size of the survey area depending on the scale of the question

Demographics

Factors that alter population size over time

Survivorship

The proportion of the cohort still alive at each age

The exponential model describes…

Population growth in an idealised, unlimited environment

The logistic model describes…

How a population grows more slowly as it nears its carrying capacity

Life History Traits

A species’ schedule of reproduction, development, and survival, which are products of natural selection

Phenology

The timing of important life cycle events such as mating, birth, or migrating

The Intermediate Disturbance Hypothesis

Creates a mosaic of habitats at different successional stages, enabling both early-colonising and late-successional species to coexist

High Disturbance Hypothesis

Most species are eliminated before they can establish, favoring only fast-colonizing “pioneer” organisms

Low Disturbance

Allows for dominant species to outcompete others through prolonged competitive exclusion, reducing diversity over time

When focusing on conservation, we look at species or populations, but…

Populations of species interact

Competition

There are a finite amount of resources on the planet, so evolution drives us to compete with others so we can survive long enough to spread our genes

Symbiosis

The relationship between two different species

Give at least one example for each

• Commensalism

• Mutualism

• Parasitism

yayyy you can do it

Explain and give examples of the following

• Intra-species competition

• Inter-species competition

yeahhhhh go girl

Dependence/Obligate Symbiotic Relationships

The more specific or “needy” species become, the more vulnerable they may be as ecosystems change

Trophic

Relating to feeding and the transfer of energy from one species to another

Communities are measured by…

Species richness (the number of species) and species diversity (the relative abundance of species)

Diverse communities are generally…

More productive year to year in terms of biomass, more stable, adapt faster, recover from stressors faster, and are more resilient to invasive species

We measure communities to…

Understand impact and change, manage biodiversity, food production, and maintain health and disease

Functional Diversity

The diversity of species that carry out the same function in an ecosystem

Biological Community

The intermediate between a population and an ecosystem, a biological community is a group of populations of different species living close enough in proximity to interact

Ecosystem

The sum of all organisms living in a given area and the abiotic factors with which they interact

Biological community interactions can be…

Competition, symbiosis, trophic, etc.

Trophic Cascades

Indirect interactions that shape communities and ecosystems in which the interactions between successive links in the food chain influences the next level through an alternating process of suppression and release

An example of a trophic cascade

know this

Predators limit…

The density of their prey, enhancing the survival of lower trophic groups

Biodiversity offers…

Resilience to the ecosystem

Top-Down Cascade

A top predator is removed, resulting in the lower tiers of consumers increasing

Bottom-Up Cascade

A disease/fire/disturbance impacts vegitation levels, resulting in the shift and decline of higher tier consumers

Disturbances prevent communities from…

Reaching a state of equilibrium in species diversity of composition

Disturbances are not always bad for every species - know an example of this

Yeeeeeehaw

The frequency of disturbance matters because…

The larger a disturbance, the more time the ecosystem requires for recovery

Ecological Succession

The process of a disturbed area being colonised by species, which are gradually replaced by other species, which are in turn replaced by yet another species

The process of ecological succession

• Disturbance

• Pioneer/colonising species

• Intermediate species

• Climax community

Pioneer species can…

• Facilitate later species by making the environment more favorable

• Inhibit later species by becoming competition for space and resources, limiting the arrival and success of later species

• Be independent of later species, with later species not influenced by conditions created by early species

How well an ecosystem responds to a disturbance depends on…

The performance of populations and interactions within the community over time

Exponential growth assumes…

Ideal conditions that are impossible to sustain in nature

Exponential Growth Model

dN/dt = rN

• N = population size

• t = units of time

• d = difference

• r = the number of additional individuals (accounting for deaths)

Logistic Growth Model

dN/dt = r_maxN((K-N)/K)

• N = population size

• t = units of time

• d = difference

• r = the maximum number of individuals

• K = karrying kapacity

By understanding that typical wild populations follow a logistic growth patter, we can calculate…

The size and frequency of resource harvests

Maximum Sustainable Yield (MSY)

Assumes that at intermediate population densities, individuals breed at the maximum rate, but down not account for size and age of individuals or the cumulative view of the impacts on an ecosystem

K-selected natural selection favors those that…

Reproduce infrequently, live long, have fewer offspring and invest high amounts of energy into offspring while living in stable environments

R-selected natural selection favors those that…

Reproduce frequently, die quickly and live fast, put no energy into raising offspring, and live in unstable environments

Be able to explain at least one example of both k- and r-selected species for the final exam

im gonna cry

Where species fall between k- and r-extremes can tell scientists…

A lot about a species’ ecology and evolution

Autotrophs

Organisms that can produce their own energy

Heterotrophs

Organisms that acquire energy by consuming other organisms

The characteristics of an ecological community are determined by…

Species diversity and trophic structure

The 4 Steps of Invasion

• Introduction

• Acclimation

• Establishment

• Landscape Spread

Subsidy Cascade

A complex interrelationship between different trophic orders in circumstances where the reduced availability of food sources is supplemented by external food sources or food sources that are not typical

The influence of keystone species

Keystone species have disproportionate levels of influence on the diversity or abundance of other species in an ecosystem (relative to the abundance of their own species)

Invasive Species in Trophic Cascades

Invasive species can alter trophic cascades by removing or becoming a top predator - this is not always bad, and can help restore an ecosystem from degradation by altering food webs

Inbreeding Depression

The reduced survivability and fertility of offspring of related individuals

Phenology

The study of the timing and cyclical patterns of events in the natural world

Allee Effect

A density-dependent phenomenon in which individual components of fitness or population growth increase as population density increases