Endangered Species

What makes a species prone to extinction? Narrow Geographical Range If they only have one specific habitat, and it is destroyed they often become (geographically extinct) Captive breeding of isolated populations in zoos often is the final state. Small Population/Low genetic diversity Small population = Lower genetic diversity = less resilient to change Large predators and extreme specialists are often in this category Low population density(Reproduction) Large territories and low populations make it tough to find each other Habitat Fragmentation contributes can make it worse Few Populations If only 2 populations (a group of the same species living in the same area capable of interbreeding) are left and one gets destroyed…

What makes a species prone to extinction? A large body Top predators = big animals = little energy = competition = rare Also often hunted for sport Low (r) Reproductive potential Slow and infrequent reproduction makes recovery tough Ex. Penguins produce one egg per pair per year Seasonal Migrants Hazardous journeys Require 2 habitats to stay in tact/healthy Habitat Fragmentation is also a problem Poor Dispersers Can’t easily move Biome shift is a big deal for these organisms

What makes a species prone to extinction? Specialist (Niche/feeding requirements) Specialists rely on constant conditions and change happens often Edible and tasty! Or valuable pelt/parts Overhunting/overharvesting

Islands Dependent on size of island and distance from shore Populations tend to be small Islands have high degree of endemic species (Narrow range) Low genetic diversity Vulnerable to introduction of non native predators

Minimal Viable Population Size The population that is needed for a species to survive in the wild Depends on many factors Genetic diversity, (r), mortality rate, growth rate, current threats For large carnivores about 500 is often considered the absolute minimum.

IUCN Red List IUCN Red List Criteria Endangered Species Act International Union for Conservation of Nature and Natural Resources (World Conservation Union) International Agency founded in 1948 Composed of 83 states, 110 GOs, and over 800 NGOs, scientists and experts from 181 countries Red List Criteria Monitor World Species through redlists Endangered Species Act 1973 United States Listing done by the Fish and Wildlife Service