Lecture 13 Flashcards
Historical Extinction
ex. dodo birds were hunted to extinction
Island Fauna Extinction
ex. snakes were introduced on an island unintentionally and eliminated 13 species of birds on an island
Extinction of once abundant fauna
ex. very abundant species of birds that were killed for food and never regenerated their species
Disease Related extinction
ex. species of frogs went extinct due to an introduction of pathogen
Extinction of biological phenomena
ex. bisons used to play a big role in ecosystems but they got hunted out of nature
Cichlid Fish Example
-Nile perch was introduced into Lake Victoria which would eat anything, producing the largest mass extinction of contemporary species, over 200 species went extinct
Consequences of Nile Perch in Lake Victoria
- initially provided a lot of food and jobs
- lead to deforestation because of the wood needed to dry the perch
- fish are smaller now because of the decrease in food for the fish, leading in fisheries closing
Fossils
physical trace left by an organism that lived in the past
Fossil Record
total collection of fossils that have been found throughout the world
Habitat Bias
some fossils were preserved better in certain environments
Taxonomic bias
organisms with hard body parts
Temporal bias
better in modern times
abundance bias
overrepresentation of things that were abundant
Causes of Cambrian Explosion: environmental change
increased oxygen concentration in atmosphere, increased thickness of ozone layer, flooding of continental shelves, increase calcium in oceans
Causes of Cambrian Explosion: Ecosystem Engineering
animals changed their environment, opening up novel ecological niches
