Hominidae is family containing great apes and humans

Species that had many similarities to humans, and that were in the genera Australopithecus and Homo have gone extinct. Homo sapiens is the only species that survives today of these two genera.

Oldest fossil species of these two genera is Australopithecus afarensis, from about 3.7

mya in the Africa

For the next 1-2 million years, our relatives lived in eastern and southern Africa in savannas

• The first fossil species of the genus Homo is Homo habilis. This species made simple stone tools which may have been used in butchering animals and to cut vegetation.

2.0 mya Homo erectus evolved

H. erectus was taller (5-6') than H. habilis, had a larger brain, and developed more advanced tools.

Did H. erectus use fire?

Fire could be used to hunt game, for protection against predators and to cook toxic chemicals out of plant foods.

Possibly the use of fire allowed H. erectus to move into other habitat types in Africa.

Check out movie, Quest for Fire

Over the next 1.4 my, H. erectus engaged in migrations within and out of Africa

Populations that evolved in sub-Saharan Africa would have to cross

the Sahara, perhaps during interglacial periods

After interglacial periods a landbridge connecting Africa and Eurasia, the Arabian peninsula, allowed H. erectus to move into Europe and Asia, about 800,000 years ago

H. erectus populations were well-distributed in Asia and Europe by 500,000 years ago

Many anthropologists believe H. sapiens evolved from H. erectus in Africa about 300,000 years ago,

again in savannas

These early men and women had heavier bones than today, thicker skulls, and brow ridges, i.e. they are archaic H. sapiens but still H. sapiens, with brains as big as modern humans.

Then, H. sapiens replaced H. erectus populations throughout world.

Neanderthals (H. sapiens)—lived in Europe, Middle East, and Asia, 130,000 to 35,000 years

ago

Neanderthals used tools and had burial rituals

Both Neanderthals and modern humans evolved from archaic H. sapiens

Hypotheses as to where modern Homo sapiens came from

Modern H.s. evolved several times from groups of archaic H.s. in Europe, Asia, and Africa.

H.s. evolved one time in Africa. Archaic H.s., Neanderthals included, were evolutionary dead ends.

Biochemists today try to recover DNA samples from fossilized skulls of Neanderthals to compare with DNA of living humans, to see whether Neanderthals contributed genes to modern pops

Work published Nov. 2006

DNA came from leg bone of male Neanderthal

Suggests Neanderthals and modern humans diverged from a common ancestor between 370,000 and 500,000 years ago

Suggests Neanderthals and modern humans did not interbreed (much?)

H. sapiens then followed the path of H. erectus into the Sahara and across the Arabian peninsula into Europe and Asia.

By 100,000 years ago H. sapiens moved out of Africa and started replacing H. erectus across its range.

How was H. erectus replaced?

Interbreeding?

Losing in competition for resources to H. sapiens?

From 75,000 to 50,000, glaciers were at a maximum around the world.

50,000 years ago there was a brief interglacial and it is at this time that first fossils of H. sapiens are found in Europe.

It is hypothesized that H. sapiens' development of projectile weapons and group hunting techniques allowed them to take relatively large game, like mammoths, whose bones could be used for tools and to construct shelters.

Theory of “creative explosion”

Modern human behavior didn’t really take off until Homo sapiens was in Europe 40,000 years ago

Modern human behavior

Refined tool-making from bones, art, symbols on tools.

Creative explosion hypothesis may be a result of a biased sampling of archaeological sites, i.e., many sites in Europe were explored while few in Africa received the same level of attention.

Recent finds from Blombos Cave in South Africa

Bone tools, some with etching on them that suggest the use of symbols, a behavior thought to be linked to abstract thought and speech.

Bone tools were likely awls for working leather, others were weapons, probably spear points.

The finds are about 70,000 years old and show that the inhabitants of the cave ate antelope and fish

40,000 to 50,000 years ago humans were up to the limits of the ice sheets in Europe and Asia.

25,000-18,000 years ago, much of northern regions was glaciated and sea level was relatively low so that Beringia formed

Shortly before 25,000 ya humans first invaded Alaska, perhaps following the species they hunted.

Even though colonists made it into Alaska, they may have been prevented from moving further south by glaciers that would have lasted until about 16,000 years ago.

When glaciers receded, colonists moved south and eventually spread throughout North and South America.

It's possible that some earlier movements occurred, if, for example, ice-free areas existed along the Pacific coast, or in the interior.

However, colonization of North and South America before about 15,000 years ago is debatable.

The range expansion of humans throughout North and South America in 15,000 years is one of the most rapid and extensive range expansions of which we have evidence.

What allowed the Homo species to expand their range so quickly?

Their ability to live in and modify their environment, e.g.

The use of tools and fire.

For example, they started building shelters.

Colonization by humans of oceanic islands was taking place concurrently with some of the events of above

Some of the islands were not islands at points in the past.

For example, colonization of the Sunda region of Asia was a result of landbridges available 75,000 years ago at a time of glaciation.

Wallacea (Sunda) was probably relatively easily colonized because the many islands were close to each over--i.e. less than 40 miles apart.

New Guinea may have been reached 70,000 years ago and then colonization of Australia and Tasmania could have occurred, again partly when landbridges were present.

Islands relatively close to Sahul like the Bismarcks were colonized by about 32,000 but more distant islands were not colonized till fairly recently (last 4000 years), when Polynesians had developed navigational abilities.

IImportant features in the evolution of population

leading to H. sapiens

Evolution of erect stance--hands are free for other activities

Enlargement of brain

Evolution of long period or parental care,, providing us with the basis of culture—accumulated knowledge, customs transmitted over generations.

Complex language

Culture is what makes human unique species, allows us to pass on knowledge which allows us to manipulate environments to meet our needs

3 stages of human culture

Scavenging/gathering/hunting Scavenging from other animals was probably important part of getting food for early humans.

Only in the last 50,000 (maybe 70,000?) years has toolmaking become sophisticated enough that hunting could make significant contribution to diet.

3 stages of human culture

Agriculture-developed in Eurasia and Americas 10-15,000 years ago

Earliest was slash and burn

As people settled down, populations became bigger.

As agriculture became more efficient, some people could specialize in other activities (technology, industry, and the arts)

3 stages of human culture

Machine age—Industrial revolution, means we have a greater need for fuel, death rates have declined, so that our population is growing.

In terms of organic evolution, we probably haven’t changed that much from our ancestors of 10,000 years ago.

Culturally, we have changed, much faster than organically

For example, 100 years ago, no one drove cars--today everyone does. This is a change in behavior caused by cultural, rather than organic evolution.

One consequence of our cultural evolution is our impact on species invasions

Species invasions and biotic homogenization

Introductions of non-native species have become more and more prevalent over time with the increasing ease with which humans traverse the globe

In historical times, many of the invasions have been a result of settlers in a new area wanting to bring familiar plants and animals with them

Most commonly introduced mammals include

• rabbits• domestic cats• several species of rats• house mice• domestic pigs• domestic cattle• domestic goats• domestic dogs

Most commonly introduced birds include

• waterfowl species

• gallinaceous birds (chickens, pheasants, etc.)

• pigeons

• parrots

Geographic patterns of introductions

Palearctic region has largest number of bird and mammal introductions and has the largest area

Australia has a large number of introductions as well, despite its relatively small size

Oceanic islands have been the hardest hit with 60% of all bird and mammal introductions

Patterns with non-native plant introductions are similar

Islands often have a substantial part of their biotas composed of non-native species.

New Zealand has approximately 1790 native plant species and 1570 exotics.

Hawaii has 1150 native plant species and 850 exotics.

Aquatic systems also affected—In Arizona, 67 of 95 breeding fish species, 71%, are non-native

Much of the biota of isolated oceanic islands is endemic, found nowhere else, making their displacement by exotics particularly harmful to global biodiversity.

The species of islands and Australia, in particular, are more vulnerable to being negatively impacted by exotics than mainland species. For example, over half of the terrestrial vertebrate species of Australia are negatively affected by exotics whereas for the other continents the value is 0-10% negatively affected.

Hawaiian birds

40% of avifauna is non-native

38 bird species introduced since 1800 as game birds or because the species were ornate

14 native species have gone extinct since 1800

New Zealand mammals

2 native species—bats

26 non-native species

Introduced species’ effects on native species

Prey on native animals and plants (reduce resource base for natives)

Carry introduced diseases

Hybridize with native species

Four subspecies of Galapagos tortoises went extinct

Introduced rats ate eggs

Introduced cats and dogs ate hatchlings

Introduced goats ate tortoises food plants

Why are island communities susceptible to exotics?

They tend to be depauperate

They tend to have small population sizes of species leading to more extinction

They tend to be isolated, with fewer chances for populations to be “rescued”

They tend to have large amounts of converted habitat

Biotic homogenization— the replacement of local biotas by non-indigenous species that can coexist

with humans

Homogecene coming?

Reduced habitat heterogeneity

Increased ease of movement between habitats

Both of the above increase homogenization

NPS and mountain goats

“conserve the scenery and the natural and historic objects and wildlife therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations".

Late 1920s 12 mountain goats (Oreamnos americanus) from Canada and Alaska were released on the northern edge of the Olympic peninsula.

By the 1980s the population had reached approximately 1200 and goats were found in groups throughout the mountain range.

Park biologists noted trampling, wallowing, and grazing of much of the vegetation, including some species that are endemic to the peninsula.

Removal efforts were initiated in the 1980s and included sterilization of individuals and live removal of some of the goats.

1990 the removal program ended, after 407 individuals had been removed from the park. Program stopped because of its expense and questions about effectiveness.

Report that came out in 2000 by independent group, Conservation Biology Institute, contracted

by the Park Service

The goats were not native

Previous studies, because of their design, had not definitively demonstrated that goats caused serious problems to populations and communities in the park

Removal was feasible

Previous reviews of potential control methods concluded that shooting is the most feasible removal method

Other techniques tried:– various types of snares and nets to catch the

goats and birth control techniques including chemical sterilization, iuds, tubal ligations and ovariectomies

Costs of techniques

Financial

Risk of injury/infection to workers/goats

Report concluded that decision had to made as to the importance of the three criteria regarding whether removal should be implemented.

As of 12-6-04 the park was continuing to monitor and census the goats but there were no removal programs planned

2005—some goats fitted with GPS radio collars to help biologists estimate numbers of goats and to look at habitat selection

2006—survey being conducted to refine census techniques