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THURS. 10/24/13Agenda: Chapter 4 Quiz Species in Danger
Life’s Work:Bring $1 for animal adoption,Read ch. 9 and study for quiz on Tues.
Objective: SWBAT define extinction and identify characteristics that make species vulnerable to extinction.
Do Now:What does it mean for something to go extinct? Name as many extinct species as you can.
Week at a GlanceMonday Tuesday Wednesday
(A)Thursday Friday
Deforestation Invasive Species and Biodiversity
Parent Conferences
Ch. 4 QuizExtinction
Animal $ dueExtinction
EXTINCTION: LIGHTS OUTExtinction: complete disappearance of a species from the Earth
Extinction occurs when the population cannot adapt to changing environmental conditions.
Extinctions have existed long before humans had an influence, but the scientific consensus is that human activities are decreasing the earth’s biodiversity.
The golden toad of Costa Rica’s Monteverde cloud forest has become extinct
because of changes in climate.
EXTINCTION: LIGHTS OUTThe current extinction crisis is the first to be caused by a single species - us!
This is happening faster than ever = a few decades instead of thousands to millions of years.
Humans are eliminating not only the species but the environments as well (ex: tropical rainforests, coral reefs, etc.)
The golden toad of Costa Rica’s Monteverde cloud forest has become extinct
because of changes in climate.
Fig. 4-12, p. 93
Tertiary
Bar width represents relative number of living speciesEra Period
Species and families experiencing
mass extinctionMillions ofyears ago
Ordovician: 50% of animal families, including many trilobites.
Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites.
500
345
Cambrian
Ordovician
Silurian
Devonian
Extinction
Extinction
Pale
ozoi
cM
esoz
oic
Cen
ozoi
c
Triassic: 35% of animal families, including many reptiles and marine mollusks.
Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites.Carboniferous
Permian
Current extinction crisis causedby human activities. Many speciesare expected to become extinctwithin the next 50–100 years.Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including manyforaminiferans and mollusks.
Extinction
Extinction
Triassic
Jurassic
Cretaceous
250
180
65Extinction
ExtinctionQuaternary Today
According to the fossil
record, there have been five major
mass extinctions
over the past 500 million
years.
Some scientists say that we are now in the midst of a 6th mass extinction,
caused by humans.
Globally / Biologically
Ecologically
Locally
Species is no longer found on the Earth
When so few members of a
species are left that they no longer play their ecological role
Species is no longer found in a particular
areaLEVELS OF SPECIES
EXTINCTION
SPECIES IN DANGEREndangered: so few
individual survivors that it could soon become extinct
Threatened: still abundant in its natural range but is
likely to become endangered in the near
future
Rare: a noticeable decline in a species