Lecture 3

Flashcards by sammibeard, updated more than 1 year ago
Created by sammibeard over 6 years ago


University Bangor year 2 Flashcards on Lecture 3, created by sammibeard on 11/10/2014.

Resource summary

Question Answer
What is a species? A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding/producing fertile offspring.
what is a morphological species? Organisms are classified in the same species if they appear identical by morphological (anatomical) criteria.
What are Phylogenetic Species? Share one morphological or molecular trait. Increase species by 48%.
What proportion of species are vertebrates? 1%
How many new species are discovered a year? 15,000
What percentage of known species have now become extinct? 99%
what percentage of present day species are predicted to go extinct> 20%
how many of the worlds' species of birds that could go extinct? 2000
What is the Bonarelli Event /Anoxic Event? occurs when the earth's oceans become completely depleted of O2 below the surface levels, may have caused mass extinction.
What is the Mega-Funa extinction? And what was the cause of it? It was the mass extinction of large land based mammals. The main cause is thought to be human hunting (74-86%)
In Madagascar, what species went extinct due to human hunting? 15 species of lemur pigmy hippo flightless elephant bird 13 species of Moas
Why have African Mega-fauna survived? Perhaps because animals coevolved with humans Animals evolved counter-adaptations to human predation
Why are islands so vulnerable? Evolved in the absence of predators Humans introduced competitors, diseases Island populations are usually small which increases their risk for extinction Rescue effect Relaxed anti-predator behavior, loss of herbivore defenses and reduced dispersal in plants
What has happened to the rate of extinction in the last 150 years? It has increased.
what percentage of vertebrates could become extinct by the end of the year? 66%
What is the increased percentage of the worlds birds that have become critically endangered? 8%
Why is this mass extinction notable? It is the only such event triggered by a single species (Homo sapien) A few million years is a long time to wait for recovery It is not clear that biodiversity will rebound this time Humans are utilizing resources that new species would need to evolve
What is an endemic species? species found naturally in only one geographic area and no place else Occupy restricted ranges
Give some examples of an endemic species? Komodo dragon lives only on a few islands Mauna Kea Silversword only lives in a single volcano crater on the island of Hawaii
If we protected 1.4% of the worlds land surface, what would that preserved? 44% of the worlds vascular plants, 35% of its terrestrial vertebrate can be preserved.
What percentage of human population are located in hotspots? 20%
Why are species going extinct in hotspots? High rates of habitat destruction Land cleared for agriculture, housing, economic development More than 70% of the original area of each hotspot has already disappeared Only 15% or less of original habitat remains in 14 hotspots 95% Brazilian forest lost 90% Madagascar forest lost
what are some of the causes of extinction (direct or indirect)? Overexploitation Habitat loss Introduced species Disruption of ecosystem interactions Pollution Loss of genetic variation Catastrophic disturbances
What is happening to the frog population around the world? Frog populations that had once been abundant are now decreasing or entirely gone 2005: 43% of amphibian species experienced decreases in population size 1/3rd are threatened with extinction
Why have some frog species declined although they live in pristine, well protected habitats? The water they have lived in are tainted in chemicals, which passes though their skin into their skin into their bodies.
What are some of the other reasons why frogs are declining in populations? Global environment is deteriorating, habitat loss and Chytrid fungus.
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