Extinction and Conservation
Worksheet 4.2
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Hannah
A ECL 365
Dr. Waldman
12-10-15
1.) What is the difference between extinction and extirpation?
 Extirpation elimination of a species in a particular location (i.e. local
extinction) but continues to exist elsewhere
 Extinction total disappearance of a species throughout its range
2.) What is background extinction? What is mass extinction?
 Background extinction normal process of species always going extinct
o 99% of ALL species that have ever lived are now extinct
 Mass extinction large ‘die-offs’ of species in relatively short time-span (at
least 60% of species within 1 million years)—(catastrophic event where
thousands of species die off)
o World-wide, affecting many species, genera, families
a. What happens after a mass extinction?
 Some remaining taxa undergo adaptive radiation as they fill out
vacated niches
3.) Fill in the table below with the details about the 5 major mass extinctions.
Who did it
impact?
Who survived/
radiated?
Ordovician
Devonian
Mostly marine
invertebrates
(at that time,
all known
animal species
lived in oceans)
Many marine
invertebrates
& 76% of
marine &
freshwater fish
families
Subsequent
rise of fishes,
origin of
amphibians
Subsequent
radiation of
amphibians on
land, origin of
reptiles
Permian
MAJOR extinction
FIRST to
significantly affect
terrestrial life: 75%
tetrapod genera, 95%
marine species, 78%
reptile & 67%
amphibian families
(global warming
event)
Subsequent radiation
of reptiles, origin of
mammals
Triassic
Cretaceous
Many longestablished
marine
invertebrates
& many
terrestrial
vertebrates
All non-avian
dinosaurs,
flying and
marine reptiles
Proliferation
of reptiles
(dinosaurs)
follows
Subsequent
proliferation of
mammals
1060 Hixson-Lied Student Success Center  515-294-6624  sistaff@iastate.edu  http://www.si.iastate.edu
4.) What are some characteristics of the Cretaceous extinction? What is the hypothesized
cause? Who was not affected?
 Large meteor hit in Yucatan
 Increased volcanic activity, increased ash/cloud cover
o Limited sunlight lead to environmental changes
 “Impact” winter (difficult for ectotherms)
 Collapse of photosynthesis (affect vegetation & food
chain)
  Herbivores die out (no food), carnivores die out (no
food)
 Omnivore, insectivore, scavengers, organisms with ties
to water (more likely to survive)
5.) Describe the 6th mass extinction. What makes it different from the other 5?
 Earth is currently in the 6th major mass extinction—current extinction rate is
significantly larger than background extinction and faster than ever before
(even Permian extinction)
 It is unique because it is caused by a single species (humans)
o Human impact on earth driving extinction of many species
a. What types of methods are causing these current extinctions?
 Human population growth
o Habitat loss and fragmentation
o Overfishing/hunting
o Invasive/introduced species
o Toxicity/contaminants
6.) ___Herps___ are currently most affected by the 6th mass extinction.
a. Specifically, ___turtles____ are the most imperiled from the vertebrate group.
(slow reproductive rate—takes long time to reach maturity; also very small
and distinct feeding/breeding grounds)
7.) Many ____amphibians_____ may be bio-indicators because of their susceptibility to
toxicity levels in the environment.
8.) What are some solutions/ conservation efforts that are being made?
 Wildlife sanctuaries/refuges
 Ecosystem/habitat restoration
 Management projects
o Wildlife corridors (connect fragmented landscapes)
o Repopulation programs
o Genetic restoration
o Captive breeding
 Invasive species management
 Green initiatives
1060 Hixson-Lied Student Success Center  515-294-6624  sistaff@iastate.edu  http://www.si.iastate.edu