Extinction of species

Genetic diversity

among individuals within a species

Species diversity

variety/ number of species in a given area 

Morphological species definition

a group of individuals that is morphologically, physiologically, or biochemically distinct from other species

Biological species definition

a group of individuals that actually interbreed or can potentially interbreed in nature, not necessarily grouped according to similarity of appearance

Evolutionary species definition

group of individuals that is evolving together and separately from other groups

Ecosystems

how species interact with each other and their environment 

Ecosystem Services

benefits provided to people from ecosystems including the preservation of individual species 

Locally extinct or extirpated

no longer found in an area it used to inhabit but is still found elsewhere

Ecologically extinct

persists in the wild at such low numbers that its effects on other species is insignificant

Mass extinction event

elevated extinction rates that lead to a sharp decrease (>75%) in the number of species in a short period of time

commodity

how much are people willing to pay when there is a market for a species

option

how much are people willing to pay to guarantee option of finding future use for species

contingent

how much are people willing to pay for the opportunity to use a species

existence

how much are people willing to pay to keep a species from going extinct (even if they never use it)

bequest

how much are people willing to pay to assure future generations have opportunity to use a species

biocentric

individual humans should respect the rights of individuals of a species

Factors causing geographical differences in species diversity

size of area, productivity, latitude, elevation, complexity, disturbance regimes

species richness

number of species

alpha

number of species in local area (average if there is larger region)

gamma

total number of species across a larger region 

beta

the change or turnover of species across a region (g/a)

Ability of species to survive environmental change

ability to move, acclimatize or adapt

speciation

evolutionary process by which multiple new species arise from a single ancestral species

speciation rate

number of new species created per unit time

biological evolution

changes in inherited traits that have a genetic basis over time

microevolution

changes in traits in a population from one generation to the next

macroevolution

creation of multiple species from a common ancestor over many generations

Darwins theory of natural selection

Different characters exist among individuals due to genetic differences and these characters are heritable

allopatric speciation

occurs when a single population is split into two populations by geographic barrier that then evolve into separate species

reproductive isolation 

If populations have diverged enough due to natural selection, they will not interbreed when they come into contact

pre-zygotic

habitat, temporal, or behavioral mechanisms that prevent the formation of viable zygotes

post-zygotic

mechanisms that prevent hybrid individuals from passing on their genes 

adaptive radiation

 surge of evolution from an original ancestral species into several new species that adapt to new environments

endangered species act

Provides a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved

The evil septet

Habitat loss, Over-exploitation, Invasive species, Disease, Climate change, Pollution, Intrinsic (or stochastic) factors

3 forms of habitat change

loss of area, fragmentation, degradation

theory of island biogeography

extinction of a species is influenced by island areas and isolation of island from other islands

metapopulation

a set of local populations connected by dispersal

local extinction

loss of all individuals from an occupied patch such that it becomes unoccupied

local colonization

dispersal of new individuals into an unoccupied patch such that it becomes occupied

metapopulation persistence

a metapopualtion can persist even if local populations go extinct as long as unoccupied patches are colonized 

edge effects

altered environmental and biological conditions at the edge of fragmentation

3 approaches to maintaining habitat

protection, management, restoration

vector

organism that transmits disease from one host to another without developing the disease itself

reservoir host

infected host that harbors a pathogen and is capable of transmitting it to other hosts

exotic

does not occur naturally in area, brought there either deliberately or inadvertently by human agency and subsequently colonized

invasive species

exotic species that become established and have adverse ecological or economic effect

characteristics of successful invaders

wide habitat tolerance, good dispersal capacity, high intrinsic growth rate, tolerant of humans

characteristics of invasible ecosystems

low species diversity, disturbed, islands, little biotic resistance from native species

controlling invasives

physical/lethal, chemical control, contraception/sterilization, biological control, prevention

vulnerable life history characteristics

naturally rare, low growth rate, large body size, patchy distributions, international range/movements

types of overexploitation

commercial, subsistence, recreational, persecution of pets, inadvertent killing

inadvertent effects of overexploitation

trophic cascades, loss of ecosystem services, decline in genetic diversity

how does climate change impact species

direct physiological, habitat changes, ecological mismatches, novel diseases,predator, competitors

ecological mismatches

changes in the timing of ecological process can prevent a species from meeting life-history needs

3 approaches for reducing effects of pollution on species

technological advances, lifestyle changes, polluters pay fines

EPA

charged with protecting human health and the environment

regulatory overreach

critics of the epa argue that it has gone too far in regulating pollution and compromised economic growth

intrinsic factors

problems inherent in small populations that have declined due to extrinsic factors, stochastic 

extrinsic factors

affect populations by deterministic processes

deterministic processes

change population size in a relatively predictable manner

stochastic processes

result in less predictable changes in population size

4 types of stochasticity that threaten small populations

genetic, demographic, environmental, catastrophes

genetic drift

loss of alleles by random chance

inbreeding depression

mating among close relatives 

density dependence

populations cannot grow indefinitely because they are limited by resources, predation or disease

allele effect

intermediate produce the most offspring

minimum viable population

smallest population that has an acceptably low extinction probability for enough time

5 ways to access species endangerment

evil sextet, intrinsic vulnerability, changes in population size and distribution, quantitative predictions of future extinction risk, rules of thumb

population viability analysis

use qualitative methods to predict the likely future status of a population or collection of populations

genetic based rule

50/500, suggest numbers enough to maintain genetic diversity in short term and long term

IUCN red list

provides the most comprehensive assessment of the level of endangerment to species

IUCN classification based off of

rate of population change, population size, geographic distribution, degree of population fragmentation, estimate of viability from a PVA

7 forms of rarity (venn diagram)

specialized habitat required, small geographic range, small population 

declining population paradigm

is the population declining, identify depressed demographic rate, natural history investigations to identify potential environmental causes, design experiment 

correlative approaches for diagnosing causes of population declines

species life history comparisons, population comparisons, timing of decline

demography toolbox

reduce mortality factors, increase reproduction, translocate, monitoring, gradients of success

in situ

protecting species in their natural habitat

ex situ

protecting species outside their natural habitats within areas equipped for preservation

translocation

international movement plants or animals

introduction translocation

moving animals outside of their native range

reintroduction

movement to places within known distribution

augmentation

addition of animals to an existing population