M3: Lecture 4 Extinction

Extinction is?

forever

Name the two species that went extinct?

tasmanian tiger and quagga

When did the last Tasmanian tiger go extinct in the Hobart Zoo?

September 7, 1936

When was the last wild Quagga probably killed by in Africa?

In the late 1870s

When did the Quagga go extinct?

August 12, 1883

Why did hunters target Quagga?

For their unique hide

What was the 4 general patterns of island endemics?

1. Limited habitat

2. Overall small population size that cannot be easily ‘rescued’ or recolonized by immigration

3. Evolved in isolation with limited competitors and predators

4. Evolved few defenses

What does a species area curve mean?

The smaller the island or area, the fewer species supported

What is species radiation?

Getting to a place with a lot of available resources to support a population

What was the example for species radiation?

Hawaiian Honeycreepers in which one ancestral finch species gave rise to as many 57 species

How many species went extinct prehistorically (Polynesian settlement)

29

How many species have gone extinct since 1778 following historical settlement?

8

Of the 20 remaining species how many are federally listed as Endangered in modern times?

14

Regarding Polynesian settlement and prehistoric extinctions, when were Hawaiian islands inhabitant by Polynesians

Around 400 AD

At the time Europeans arrived in the late 1700s the islands were inhabited by how many people?

200K

What from their culture aided in prehistoric extinctions? (4)

1. Intense agriculture of land at lower elevation

2. Forest cutting and burning

3. Hunting

4. Introductions of pigs, rats, exotic instead and plants

What did fossil records show regarding native bird species and Polynesian colonization?

More than half of native bird species were present when Polynesians colonized and they went extinct before the Europeans arrived. So by the time the Europeans arrived the most extinction prone animals were already gone

When did the wild population of Hawaiian Goose fall to 30-50 birds?

1940s-1950s

What were the issues to the Hawaiian Goose decline?

Introduced mongoose, cats, dogs, pigs, rats (predators)

What began in the late 1940s as a response to the Hawaiian Goose decline?

Captive breeding, reintroductions, predator controls began in the late 1940s

When was the Hawaiian Goose listed as Endangered under previous legislation before the ESA?

1967

When did the endanger species status of the Hawaiian Goose carry over the ESA?

1973

How many adults of Hawaiian Goose are there roughly now?

3800 adults

When was the Hawaiian Goose down listed to Threatened?

2019

What 4 factors did the loss and decline of the Hawaiian Native Birds result from?

1. Habitat loss and degradation

2. Predation by introduced mammals, and other exotic species

3. Competition from introduced bird species

4. Susceptibility to introduced bird diseases

What bird disease was introduced?

Avian malaria transmitted by introduced mosquito species

In the US was are the leading causes for species declines?

Habitat loss/degradation

Exotic species

Climate (argued)

What are extinction prone species? (2)

Species that require large terroritories and Species with very limited natural ranges

What 4 factors make up species that require large terroritories?

1. Habitats susceptible to loss, fragmentation, or degradation

2. Low rates of reproduction

3. Often limited population sizes

4. “K-selected” species

What are “K-selected” species?

Species perceived to be at their carrying capacity with low numbers of births which their parents or herds allocate more resources and care to.

What 3 factors make up species with very limited natural ranges?

1. Habitat susceptible to loss or degradation

2. Often limited population size

3. Island endemic species

What was the example for extinction prone species?

Condors

What are condors? What do they do and what do they require?

They are huge birds that soar over huge expanses in search of food such as large dead animals to scavenge. They require large amounts of space

How many condors were there by 1982

only 22 condors

What 3 threats are there to condors?

1. Shooting

2. Powerlines, fences

3. Contamination - poisoned from consuming lead shot from shot animals during hunting season that did not die right away and ran off before they died

Review: When was the Younger Dryas ?

14-12.9 thousands of years ago

Review: What was the Younger Dryas?

A climatic pattern at the end of the last glacial period that may be haven different than earlier glacial-interglacial transitions.

Review: What happened with the Northern Hemisphere during the Younger Dryas?

The Northern Hemisphere plunged back into and then out of glacial conditions within decades.

Review: How has the Younger Dryas been used as evidence?

To argue that these climatic shifts are an abnormal thing and could be behind the cause of the extinction of large mammals

What is the total population of condors worldwide as of 2025?

607

What was the second example of extinction prone species?

Grizzly bears

Where are Grizzly bears managed?

Greater Yellowstone Ecosystem

What important point was revisited about parks and iconic species?

Most of the biggest parks and reserves are not big enough to protect many of our iconic species

What are the two major effects from habitat fragmentation that reduce species survival in an area?

1. Reduces total habitat area: primarily affects population size

2. Redistribution of remaining habitat into patches or fragments: affects survival and dispersal of species

As habitat is fragmented, the ____ the habitat patch is, the ___ individuals (or species) can be supported by the patch. What is this derived from?

smaller, fewer

Derived from the species area curve

What is the Great Basin considered?

A non equilibrium meta population

Why is the Great Basin considered a non equilibrium meta population?

Because species can not make the movement due to unfavorable conditions