UNIT 2: The Living World Biodiversity

Biodiversity

is the variety of life on Earth

Genetic Diversity

The total number of genetic characteristics and different DNA traits (alleles) found within a single species or population.High genetic diversity helps a population withstand (resist) and recover (rebound ) from environmental stressors. This is because there is a greater chance that some members of the population will have genetic charateristics (such as disease resistance) that allow them to survive.

Species Diversity

The variety and relative abundance of different species living within a specific region or ecosystem. It includes both species richness (how many types there are) and evenness (how evenly distributed their population numbers are). More species mean a wider array of ecological roles (like pollination and nutrient cycling), making the whole natural system more resilient to disturbances.

Habitat Diversity

The variety of different ecological communities, physical landscapes, and habitats (like forests, rivers, and deserts) found in a given area.A greater variety of habitats creates more ecological niches, which directly supports higher species and genetic diversity

Bottleneck Effect

a sharp reduction in population size that leads to a loss of genetic diversity

Ecosystem Resilience

ecosystems with large amounts of biodiversity are more likely to recover from disruptions. High species richness means that if one species is lost, another can fill ecological roles!

Habitat Loss

specialized species disappear first, followed by generalist species. Individuals requiring large territories are heavily impacted.

Species Richness

refers to the number of different species in an ecosystem

Species Evenness

is the number of individuals within each species in a given area.

Species Biodiversity

is determined by both evenness and richness

Provisioning Service

physical goods extracted from nature such as timber, food, and medicines

Regulating Service

natural processes moderated by ecosystems such as climate regulation, flood mitigation, and water purification

Supporting Service

underlying processes necessary for all other services such as photosynthesis, nutrient cycling, and soil formation

Cultural Services

non-material benefits that enrich human lives such as recreation, tourism, and spiritual experiences

Human disruptions

anthropogenic (human-caused) activities disrupt these services, causing economic and ecological damage such as fossil fuel combustion deforestation, and urbanization

Island Biogeography

is the study of the ecological relationships and distributions of organisms on islands and how these communities are structured. Islands that are closer to other land and that are larger maintain higher biodiversity than smaller, further islands. Islands that have been colonized in the past by species arriving from somewhere else

Habitat Isolation

the concept applies to isolated, fragmented patches of habitat on land, not just islands on water

Specialist Vulnerability

island species are usually specialists due to limited resources. They are easily outcompeted by invasive generalist species

Ecological Tolerance

is the range of environmental conditions such as temperature, salinity, flow rate, sunlight) a species can endure before dying. When organisms move outside their natural range, they can experience physiological stress, which can lead to impaired body function, reduced growth, decreased reproductive success, and potentially death.

Natural Disruptions

can have consequences that are as great, if not greater than many anthropogenic (man-made) disruptions. Earths natural processes operate on a periodic (regular), episodic (irregular), or random timeframe.Earths climate has changed over geological time for many reason such as variation in the Earths orbit, changes in solar radiation, volcanic eruption,and shifts in greenhouse gas levels)

Sea Level

has varied as a result of changes in glacial ice on Earth over time. Melting of the polar ice caps or of glacial/land-based ice can cause sea levels to rise; ice already floating in the oceans will not

Major environmental changes…

result in habitat changes

Wildlife engages in…

both short term and long term migration for a variety of reasons, including natural disruptions

Genetic Adaptations

populations adapt over time via small genetic changes, which can happen on both short and long-term scales

Surivival Pressures

sudden or gradual environmental changes force individuals to alter their behavior, move to a new location, or face dying out

Natural Selection

adaptations develop across generations through the process of natural selection

Succession

categorized into primary succession (occurs where there is no pre-existing soil) and secondary succession (occurs where soil is already present after a disturbance)

Keystone Species

is a species whose activities have a particularly significant role in determining community structure

Indicator Species

is a plant or animal that by its presence , abundance, scarcity, or chemical compositions, shows some aspect of the character or quality of ecosystems

Pioneer Species

early successional species move into unoccupied areas, and over time adapt to its particular conditions, which may result in speciation. Pioneer species for primary succession are lichens and moss. For secondary succession tends to be grasses and weeds.

Primary Succession

no soil or life present, just rock

Secondary Succession

occurs when soil is already present

Succession

in a disturbed ecosystem will affect the total biomass, species richness, and net productivity over time