ENVS Dr. Moreno Exam 2

based on lecture

genetic diversity

all the different genes contained in all individual plants, animals, fungi, microorganisms

species diversity

all the differences within and between populations of a species, as well as between different species

ecosystem diversity

all the different habitats, biological communities, and ecological processes, as well as variation within individual ecosystems

Functional diversity

Ecological roles in a system

Vertical Diversity

Different layers of organisms that occupy a vertical space

Horizontal Diversity

spacial distribution of organisms across a horizontal space

Structural Diversity

Different morphological structures within a system

Example of Structural Diversity

Shade grown coffee plantation

Temporal diversity

Variations in the pattern of biotic and abiotic change over time

Biodiversity

The concept of variation within and among individual organisms, biotic populations and communities, ecosystems, biomes, as well as variation in the biotic and abiotic processes that time them together

Ways to assess biodiversity

Species richness, species evenness, Shannon index

Species richness

The number of species present in a given area

Species evenness

relative abundance of species in a given area

Shannon Index (H)

Value that describes number and proportionality of species

Shannon Index Formula

Shannon Index (H) = -Σ (pᵢ * ln(pᵢ)) where pᵢ = proportion of each species.

The 5 threats to biodiversity

Climate change, habitat loss/fragmentation, invasive species, pollution, overexploitation

Acronym to remember 5 threats to biodiversity

CHIPO

Biological communities

multiple species in a given area

Common characteristics of community structure

Community composition is dynamic and changes over time, composition of a community is shaped by abiotic and biotic factors, communities are composed of numerically dominant and subdominant species

Example of Community Structure

Cat Island, Tashirojima Japan. Silkworm trade booms, mice find their way to island and start eating the silkworms so people leave the island, cats are introduced to decrease mice population

Species Abundance Distribution (SAD)

Numerically dominant are a few species that comprise about 70% of all individuals in a community whereas the numerically subdominant are the majority of species but only comprise 30% or less of all individuals

Examples of SAD

Upstate New York Bird Study, Beetles in Freshwater streams in UK, United States plains grasses in grasslands

Top 3 factors that drive numeric dominance and subdominant (in order)

Competition , predation, reproductive ability

Example of Competition driving ND/SD

Paramecium caudatum and Paramecium aurelia. When grown together aurelia (ND) outcompeted caudatum (SD). When grown separate: caudatum reaches ~70 cells, aurelia reaches ~250 cells. When grown together: caudatum reaches ~10 cells then dies, aurelia still reaches ~250 cells

Example of Predation driving ND/SD

Snowshoe hare and arctic fox

Islands are biodiversity hotspots because

they cover ~7% of global surface area but have ~20% of all plant and animal species

Endemism

a species is only found in one specific place

Theory of Island Biogeography

Species richness on islands based on immigration/colonization and extinction. The closer the island is the to mainland the larger the species richness

Colonization Island Biogeography Model

As the number of species increases the rate of colonization decreases. The island is more populated and the chances are lower that an individual that arrives is a new species

Extinction Island Biogeography Model

As number of species increases, extinction rate increases due to composition. Smaller islands have higher extinction rates

Equilibrium points Island Biogeography Model

the number of species you would prediction on an island. where the number of new species that arrives each year is equal to the number of species that go extinct each year

Rank of most species to least species TIB

Most to least: Large near, small near, large far, small far

Example of TIB

Cuba and Hispaniola have more richness out of the Caribbean islands as they are larger and closer to mainland. Islands such as Jamaica have less

Island Biogeography Model

Density dependent factors definition

population limiting factors that depend on size of population

Density independent factors definition

Population limiting factors that do not depend on the size of a population

Examples of density dependent factors

Disease, predation, competition

Examples of density independent factors

natural disasters, pollution, climate

Positive density dependence

as population density increases factors that grow population increase

Example of positive density dependent factors

predation, resource abundance, genetic diversity

Negative density dependence

as population density increases factors that shrink population increase. population is reduced as density increases

example of negative density dependent factors

conflict, competition, disease

Example of species change due to density

Locusts (Shistocerca gregaria var. solitana) transforms into var. gregaria triggered by overpopulation. Their legs touching each other triggers the change. they revert back after finding new resources