How a new species of ancestors is changing our theory of human evolution | Juliet Brophy

Translator: Leslie Gauthier Reviewer: Krystian Aparta

Prevoditelj: Katarina Mikjel Recezent: Ivan Stamenković

Human origins.

Podrijetlo ljudi.

Who are we?

Tko smo mi?

Where do we come from,

Odakle smo došli

and how do we know?

i kako to znamo?

In my field, paleoanthropology,

Moja struka, paleoantropologija,

we explore human origins --

istražuje podrijetlo ljudi –

the "who" and "where" questions --

odgovaramo na pitanja „tko“ i „zašto“ –

by analyzing fossils that date back thousands and even millions of years.

analizirajući fosile stare tisuće i milijune godina.

In 2015, a team of colleagues and I named a new species in the genus Homo --

Godine 2015. skupina kolega i ja otkrili smo novu vrstu u rodu Homo –

our genus --

našem rodu –

Homo naledi.

i nazvali je Homo naledi.

Let's take a step back and put that into context.

Vratimo se malo unatrag kako bismo to stavili u kontekst.

The last common ancestors between humans and chimps

Posljednji zajednički preci ljudi i čimpanza

date somewhere between six and eight million years.

živjeli su prije otprilike 6 – 8 milijuna godina.

The earliest hominins,

Najstariji hominini,

or earliest human ancestors,

tj. najraniji ljudski preci,

evolved into a group known as the australopithecines.

evoluirali su u skupinu poznatu kao australopitecini.

The australopithecines evolved into the genus Homo

Australopitecini su evoluirali u rod Homo

and eventually modern humans -- us.

i naposljetku u moderne ljude – nas.

With each new fossil discovery,

Svakim novim otkrivenim fosilom

we get a little bit closer to better understanding who we are

bolje razumijemo tko smo

and where we came from.

i odakle smo došli.

With these new fossil finds,

Zbog tih novih fosilnih nalaza

we realize we now have to make changes to this tree.

shvatili smo da moramo promijeniti ovo stablo.

Until this discovery,

Do ovog otkrića

we thought we had a pretty good idea about the patterns of evolutionary change.

mislili smo da prilično dobro poznajemo obrasce evolucijskih promjena.

Current fossil evidence suggests

Prema sadašnjim fosilnim dokazima,

that the earliest populations of the genus Homo evolved in Africa

najranije populacije roda Homo pojavile su se u Africi

somewhere between two and three million years.

prije otprilike 2 – 3 milijuna godina.

Fast-forward to approximately 300,000 years to where we see the origins

Skoknimo sad u doba prije oko 300 000 godina kad su se pojavili

of the first modern humans.

prvi moderni ljudi.

While the fossil record between these time frames in Africa

Iako su fosilni dokazi u razdoblju između ta dva datuma u Africi

is relatively sparse,

relativno malobrojni,

the fossils nonetheless demonstrated certain trends

ipak pokazuju određene trendove

from our earliest ancestors to modern humans.

u razvoju naših najstarijih predaka u moderne ljude.

For example, our brains were becoming larger

Na primjer, naši su se mozgovi sve više povećavali

relative the rest of our body.

u odnosu na ostatak našeg tijela.

Our pelves were becoming more bowl-shaped,

Naše zdjelice dobivale su oblik zdjele,

and our hand-wrist morphology, or form,

a oblik naše šake i zapešća

suggested a change in our grip as we began to make and use stone tools

odražava promjenu u stisku do koje je došlo zbog izrade i uporabe kamenog oruđa

and spend less time in the trees.

i sve kraćeg boravka na stablima.

These new fossils disrupt everything we thought we knew about these trends

Otkriće novih fosila remeti sve što smo mislili da znamo o tim trendovima

and force us to change the way that we think about human evolution.

i sili nas da promijenimo način na koji razmišljamo o ljudskoj evoluciji.

South Africa in general,

U južnoj Africi,

but the Cradle of Humankind in particular,

posebice u Kolijevci čovječanstva,

contains numerous sites where hundreds of thousands of fossils have been found.

pronađene su stotine tisuća fosila.

As an undergraduate student, I fell in love with one of them ...

Kao studentica preddiplomskog studija zaljubila sam se u jednoga od njih...

Mrs. Ples.

... gospođu Ples,

The skull of a 2.1-million-year-old early human ancestor.

lubanju ranog ljudskog pretka, staru 2,1 milijun godina.

From that point on,

Od toga sam trenutka

I was determined to go to South Africa and study human evolution.

čvrsto odlučila otići u južnu Afriku i proučavati ljudsku evoluciju.

I first traveled there in 2003,

Prvi sam put otputovala tamo 2003.

and I did get to see my beloved Mrs. Ples.

i doista vidjela svoju miljenicu gđu Ples.

(Laughter)

(Smijeh)

But words can hardly convey my excitement

No teško je riječima izraziti moje oduševljenje

when I was chosen as an early career scientist

kad me je kao mladu znanstvenicu izabrao

by Lee Berger,

Lee Berger,

a world-renowned paleoanthropologist,

paleoantropolog svjetskoga glasa,

to be one of the primary analysts of recently excavated unpublished fossils.

za jednu od prvih analitičara neobjavljenih fosila iskopanih nedugo prije toga.

This treasure trove of fossils was being recovered from a new site

To veliko fosilno blago pronađeno je na novom nalazištu,

called the Dinaledi Chamber in the Rising Star cave system.

u tzv. komori Dinaledi u spiljskom sustavu Rising Star.

Species are often named based on a skull, a lower jaw,

Vrste često dobiju ime po lubanji, donjoj čeljusti

or, very rarely,

ili, vrlo rijetko,

a handful of postcranial, or below-the-neck, elements.

po nekoliko postkranijalnih elemenata, tj. onih ispod vrata.

The fossils from Dinaledi were another story altogether.

Fosili iz Dinaledija posve su druga priča.

An unprecedented approximately 1800 specimens --

Nezapamćena količina od 1 800 fragmenata kostiju –

so far --

do sada –

have been excavated from the Rising Star system,

iskopana je u sustavu Rising Star,

representing at least 15 individual skeletons.

a potječu od barem 15 pojedinačnih kostura.

The research team that I was invited to join

Skupina istraživača kojoj sam se pridružila

was tasked with describing, comparing and analyzing the fossils,

imala je zadatak opisati, usporediti i analizirati fosile

with the difficult goal of identifying to what species the fossils belonged.

kako bi se odredilo kojoj vrsti pripadaju.

We were divided up into our different areas of expertise.

Bili smo podijeljeni prema područjima stručnosti.

We were divided up in different areas of the lab, too.

I naš je laboratorij bio podijeljen na razna područja.

So there was "Hand Land," for the fossil hand people,

Bilo je ondje „Šakozemlje” za one koji su se bavili fosilima ljudskih šaka,

"Hip Heaven" for the pelvis ...

„Rajski kuk” za zdjelice itd.

I was in the "Tooth Booth."

Ja sam bila u „Zubokutku”.

(Laughter)

(Smijeh)

And after long, intense days in the lab,

Nakon dugog, intenzivnog dana u laboratoriju,

the different teams would meet up at night and discuss our findings,

različite skupine sastajale bi se noću i raspravljale o svojim nalazima,

still consumed by questions from our analyses.

još zaokupljene pitanjima koja su proizlazila iz naših analiza.

It was incredible how different the interpretations were.

Nevjerojatno je koliko su se tumačenja razlikovala.

Each body part seemed to come from a different species,

Svaki dio tijela kao da je potjecao od različite vrste,

based on what we knew from the fossil record.

prema onome što smo dotad saznali iz fosilnih nalaza.

The suite of characteristics we were seeing didn't match any known species.

Skup osobina s kojima smo se tada susreli nije odgovarao ni jednoj poznatoj vrsti.

And if we had only recovered the skull, we might have called it one thing;

Da smo pronašli samo lubanju, nazvali bismo je jednim imenom;

if we had only recovered the pelvis, we might have called it another.

da smo pronašli samo zdjelicu nazvali bismo je nekim drugim.

The anatomy of the skeletons didn't make sense

Anatomija kosturâ nije se uklapala

with the framework of what we thought we knew of human evolution.

u ono što smo mislili da znamo o ljudskoj evoluciji.

Did it belong in the genus Homo?

Pripadaju li rodu Homo?

Should it be an australopithecine?

Jesu li australopitecini?

Those bipedal, more apelike ancestors?

Neki od dvonožnih predaka sličnijih majmunima?

Or perhaps it should be its own species.

Ili je možda riječ o zasebnoj vrsti?

Ultimately, after much deliberation,

Naposljetku smo, nakon mnogo razmatranja,

we decided the Rising Star specimens did indeed warrant a new species,

zaključili da primjerci iz spilje Rising Star doista pripadaju novoj vrsti,

which we called "Homo naledi."

koju smo nazvali „Homo naledi”.

From the head to the feet,

Od glave do pete

the fossils present a mosaic of primitive, or ancestral,

fosili su mozaik primitivnih, tj. naslijeđenih,

and derived or more modern-like features.

i stečenih, tj. modernijih osobina.

The skull is quite derived,

Lubanja je prilično razvijena

appearing most similar to early representatives of the genus Homo,

i čini se najsličnija ranim predstavnicima roda Homo,

like Homo habilis and Homo erectus.

kao što su Homo habilis i Homo erectus.

However, the brain is scarcely half the size of a modern human one.

Međutim, mozak je jedva upola velik kao onaj modernih ljudi.

One that is smaller than any other early Homo that has ever been found.

Manji je od mozga bilo kojeg drugog dosad pronađenog pripadnika ranog roda Homo.

As someone who studies teeth,

Kao osoba koja proučava zube,

I might argue these are the coolest fossils found at the site.

mogla bih reći da su upravo to najkul fosili pronađeni na nalazištu.

(Laughter)

(Smijeh)

The assemblage consists of 190 whole or fragmentary teeth

Kolekcija sadržava 190 cijelih ili fragmentarnih zubi

that range in age from very old to very young.

različite starosti – od vrlo starih do vrlo mladih.

Like the skeletons,

Baš poput kosturâ,

the teeth present a mix of primitive and derived traits.

zubi su mješavina primitivnih i stečenih značajki.

In modern humans,

Kod modernih je ljudi

the third molar is typically the smallest, while the first molar is the biggest,

treći kutnjak obično najmanji, dok je prvi kutnjak najveći,

but Homo naledi has the primitive condition

no vrsta Homo naledi ima primitivnu značajku:

where the third molar is the biggest and the first molar is the smallest.

treći kutnjak joj je najveći, a prvi najmanji.

The anterior teeth,

Prednji zubi,

or the incisors and canines,

tj. sjekutići i očnjaci,

are small for the genus Homo,

premali su da bi pripadali rodu Homo

and the lower canine has a cuspulid on it --

a donji očnjak ima

an extra cuspule that gives it a distinct mitten-like shape

dodatnu kvržicu koja mu daje izrazit oblik rukavice s palcem

that it shares with some specimens of the early human, Homo erectus.

koje imaju neki primjerci ranih ljudi, vrste Homo erectus.

The overall shape of the teeth looked odd to me,

Oblik zubi izgledao mi je čudno,

so I performed crown-shape analysis

pa sam analizirala oblik krune

on the occlusal surfaces of deciduous teeth, or baby teeth --

na okluzijskim površinama mliječnih zubi –

on your left --

s vaše lijeve strane –

and the permanent premolars and molars on your right.

i trajnim pretkutnjacima i kutnjacima s vaše desne strane.

The deciduous teeth are especially narrow,

Mliječni su zubi posebice uski,

and the premolars are unique in their outline shape

a oblik obrisa pretkutnjaka jedinstven je

compared to other hominids.

u usporedbi s ostalim hominidima.

In fact, when I compare the outlines,

Ustvari, kad usporedim obrise,

when I lay them on top of each other,

kad ih stavim jedan na drugi,

they look very similar.

izgledaju vrlo slično.

We say they have "low intraspecific variations,"

Kažemo da je „mali broj intraspecifičnih varijacija“,

so the variation within the species is low.

što znači da je malo varijacija unutar vrste.

When I compare this to groups like the australopithecines,

Kad to usporedim sa skupinama kao što su australopitecini,

the intraspecific variation is much larger.

broj intraspecifičnih varijacija mnogo je veći.

Postcranially, the team concluded

Što se tiče ostatka kostura, zaključili smo

that the position of the shoulders suggesting naledi was a climber;

da su položaj ramena koji upućuje na to da je H. naledi bio penjač,

the flared pelvis and curved fingers are all primitive for the genus Homo.

proširena zdjelica i zakrivljeni prsti previše primitivni za rod Homo.

On the other hand,

S druge strane,

the humanlike wrist, long slender legs and modern feet

po zapešću nalik ljudskome, dugim vitkim nogama i modernim stopalima

are all consistent with other members of the genus.

slični su drugim članovima tog roda.

In 2017, we announced more specimens of Homo naledi

Godine 2017. izvijestili smo o novim primjercima vrste Homo naledi

from the nearby Lesedi Chamber,

otkrivenim u obližnjoj komori Lesedi,

also in the Rising Star cave system.

još jednom dijelu spiljskog sustava Rising Star.

In addition, our geology team managed to produce an age estimate.

Usto je naš geološki tim uspio datirati nalaze.

The date's a big deal because, up until now,

Datacija je vrlo značajna jer smo sve dosad

we had based our analysis solely on the morphology of the specimens,

svoju analizu temeljili samo na morfologiji primjeraka

without previous knowledge of how old something is --

bez prethodnog poznavanja njihove starosti –

something which could unconsciously bias our interpretations.

kako ona ne bi slučajno utjecala na naša tumačenja.

With its small brain and flared pelvis,

S obzirom na mali mozak i proširenu zdjelicu,

we would not have been surprised

ne bi nas iznenadilo

if the fossils turned out to be two million years old.

da su fosili bili stari i do dva milijuna godina.

Instead, the fossils dated

Umjesto toga, bili su stari

to 235 to 336 thousand years,

235 – 336 tisuća godina,

an incredibly young date for such a small-brained individual.

što je nevjerojatno kasno za jedinke s tako malim mozgom.

So think back to what I said earlier:

Prisjetite se onoga što sam ranije spomenula:

we thought that our brains were becoming larger relative to the rest of our body.

dosad smo mislili da su se naši mozgovi povećavali u odnosu na ostatak tijela.

Now we have a small-brained, young individual complicating this idea.

Sad pak imamo jedinku kasnog datuma s malim mozgom, što komplicira stvari.

What does all this mean?

Što sve to znači?

Homo naledi has taught us

Homo naledi naučio nas je

that we need to reassess what it means to be in the genus Homo.

da moramo preispitati što znači pripadati rodu Homo.

We need to rethink what it means to be human.

Moramo preispitati što znači biti čovjek.

In fact, most of the characteristics that we use to define the genus Homo,

Ustvari, mnoge značajke s pomoću kojih smo definirali rod Homo,

such as brain size and hip morphology,

kao što su veličina mozga i morfologija kuka,

are no longer valid.

više ne vrijede.

No other species exists with this mix of primitive and derived traits.

Ne postoji druga vrsta s takvom mješavinom primitivnih i stečenih osobina.

Why is there so much morphological variation in the genus Homo?

Odakle takva morfološka varijacija u rodu Homo?

And what force is driving that variation?

I koji je uzrok toj varijaciji?

Another implication for these fossils is that for the first time,

Ovi fosili značajni su i zbog toga što prvi put

we have concrete evidence of a species coexisting in Africa,

imamo konkretne dokaze o istovremenom postojanju određene vrste u Africi,

at 300,000 years,

prije oko 300 000 godina,

with modern humans.

i modernih ljudi.

Until this discovery,

Do tog otkrića

we only had large-brained modern humans that existed in Africa.

mislili smo da su u Africi živjeli samo moderni ljudi velikoga mozga.

Jesu li se pripadnici dviju vrsta međusobno razmnožavali?

Did they interbreed with each other?

Did they compete with each other?

Jesu li bili konkurencija?

Another implication that these fossils have

Ti fosili značajni su i

is for the archaeologists studying stone tools in South Africa.

za arheologe koji proučavaju kameno oruđe u južnoj Africi.

Keep in mind that neither the Dinaledi nor the Lesedi Chambers

Imajte na umu da ni u komori Dinaledi ni u komori Lesedi

have any artifacts in them.

nisu pronađeni artefakti.

However, they do overlap in time with several stone-tool industries,

Međutim, njihovo se postojanje vremenski podudara

s nekoliko industrija kamenog oruđa

the makers of which are considered to be either modern humans

čije se tvorce smatra ili modernim ljudima

or direct human ancestors.

ili izravnim ljudskim precima.

This begs the question:

Postavlja se pitanje:

Who made the stone tools of South Africa?

tko je izradio kameno oruđe u južnoj Africi?

Veličina mozga dosad se smatrala ključnim pokazateljem

Brain size has historically played a key role

in identifying a species as a tool user.

s pomoću kojeg se moglo odrediti je li se određena vrsta služila oruđem.

The idea is that you need to have a large brain

Smatralo se da je potreban velik mozak

to have even the capacity to make stone tools.

da bi se imalo sposobnost izrade kamenog oruđa.

But that notion has been questioned.

No ta je zamisao sada upitna.

Furthermore, Homo naledi, even with its small brain size,

Štoviše, Homo naledi čak i sa svojim malim mozgom

has a hand-wrist morphology similar to other species

ima morfologiju šake i zapešća sličnu onoj drugih vrsta

that did make and use stone tools,

koje su izrađivale i upotrebljavale kameno oruđe,

suggesting it had the capability.

što bi moglo značiti da je bio sposoban za to.

With two species coexisting in Africa at 300,000 years,

Sad kad znamo da su dvije vrste istovremeno postojale u Africi

prije 300 000 godina,

we can no longer assume we know the maker of tools

ne možemo sa sigurnošću tvrditi da znamo tko su tvorci oruđa

at sites with no associated species.

na nalazištima gdje nisu otkriveni nikakvi ljudski nalazi.

So where does Homo naledi fit in our human evolutionary lineage?

Dakle, kako se Homo naledi uklapa u evolucijsku liniju ljudi?

Who is it most closely related to?

Tko mu je najbliži srodnik?

Who did it evolve from?

Od koga se razvio?

We're still trying to figure all that out.

Još uvijek to pokušavamo dokučiti.

It's ironic, because paleoanthropologists are renowned

Ironija je u tome što su paleoantropolozi čuveni

for having small sample sizes.

po tome što raspolažu malim uzorcima.

We now have a large sample size,

Sad imamo na raspolaganju veliki uzorak,

and more questions than answers.

a više je pitanja nego odgovora.

Homo naledi has taught us,

Homo naledi nas je naučio,

has brought us a little bit closer

još malo približio,

to better understanding our evolutionary past.

boljem razumijevanju naše evolucijske prošlosti.

So while Mrs. Ples will always hold a special place in my heart,

Iako će gđa Ples zauvijek imati posebno mjesto u mojem srcu,

she now shares that space with several thousand others.

sada ga dijeli s nekoliko tisuća drugih.

(Laughter)

(Smijeh)

Thank you.

Hvala vam.

(Applause)

(Pljesak)