首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、Their genetic makeup began to change. B、Their communities began to grow steadily. C、Their children began to mix with each othe
A、Their genetic makeup began to change. B、Their communities began to grow steadily. C、Their children began to mix with each othe
admin
2021-01-08
22
问题
Skin may seem like a superficial human attribute, but it’s the first thing we notice about anyone we meet. As a zoologist focusing on the studies of apes and monkeys, I’ve been studying why humans evolved to become the naked ape, and why skin comes in so many different shades around the world. We can make a very good estimate from the fossil record that humans probably evolved naked skin around 1.5 million years ago, and meanwhile they mostly lost their coat of fur.
Today we have a few patches of hair remaining on various parts of our bodies. But compared with apes and monkeys, we have very little. Basically, we turned our skin darker to serve as a natural sun protector in the place of the hair we lost. We think we lost this hair because of the need to keep ourselves cool when we were moving around vigorously in a hot environment. We can’t really lose heat by breathing quickly and loudly like dogs. We have to do it by sweating. So we evolved the ability to sweat plentifully and lost most of our fur. Most animals protect themselves from the sun with fur. What we did in our ancestry was to produce more permanent natural coloring in our skin cells. This was really an important revolution in human history because it allowed us to continue to evolve in equatorial environments. It really made it possible for us to continue along the path toward modern humans in Africa.
For most of human history, we all had dark skin. What we see today is the product of evolutionary events resulting from the dispersal of a few human populations out of Africa around 60,000 to 70,000 years ago. Our species originated around 200,000 years ago and underwent tremendous diversification— culturally, technologically, linguistically, artistically— for 130,000 years. After that, a few small populations left Africa to populate the rest of the world. These early ancestors of modern Eurasians dispersed into parts of the world that had more seasonal sunshine and much lower levels of sun radiation. It’s in these populations that we begin to see real changes in the genetic makeup of natural coloring.
Today, skin color is evolving in the new mixtures of people coming together and having children with new mixtures of skin color genes. We can see this in almost every large city worldwide. Not only the coloring genes but lots of other genes are getting mixed up, too.
Questions 22 to 25 are based on the recording you have just heard.
22. What does the speaker mainly talk about?
23. What had probably caused humans to lose most of their hair 1.5 million years ago?
24. What does the speaker say protected early humans from the sun?
25. What happened after humans migrated from Africa to other parts of the world?
选项
A、Their genetic makeup began to change.
B、Their communities began to grow steadily.
C、Their children began to mix with each other.
D、Their pace of evolution began to quicken.
答案
A
解析
讲座中提到,一部分人离开非洲来到了世界各地。他们来到那些拥有四季变化、日晒也不那么强烈的地方,体内的天然色素的基因构成开始发生变化。因此答案为A)。
转载请注明原文地址:https://jikaoti.com/ti/kjBFFFFM
0
大学英语六级
相关试题推荐
Peopleatthelowerendoftheincomescaletakemorepleasureintheirrelationshipsandenjoycaringforandconnectingwitho
A、Engageininterestingdebatesoften.B、Speaktoourselvesinfrontofamirror.C、Talkwithfriendsaboutdifferenttopics.D、
A、Smallclassesmaymeeteverychild’sparticularneeds.B、Somechildrenfallbehindtheothers.C、Teachersdon’tpayattention
A、Tosuggestandassistchildren’splay.B、Togivechildrenopportunitiestoplay.C、Tomakechildrenexcited.D、Topreventchil
ThedirectraysofthesuntouchtheequatorandstrikenorthwardtowardtheTropicofCancer.IntheSouthernhemispherewinter
Memoryappearstobestoredinseveralpartsofthelimbic(边缘的)systemofthebrain,andanyconditionthatinterfereswiththef
珍稀动物
A、TheygotsuccesswiththetrackParklife.B、TheyweredefeatedbyOasis.C、Theyweretheroughworkingclassrockers.D、Theyr
Innovation,theeffectiverecipeofprogress,hasalwayscostpeopletheirjobs.Overthepast30yearsthedigitalrevolutionh
A、Personalinstincts.B、Behavioralchanges.C、Conversationvideos.D、Psychologicalresearches.BBrinke博士的调查指出,运用一些客观、有理有据的生理和行为变
随机试题
Nocredit,badcredit:hearthetermsoftenenoughandtheycanblurtogether.Thesecreditstatusesaren’toneandthesame,though
康德所说的“一位好名声的人死后继续存在的权利”,指的是
泰嘉贸易公司从国外购进100吨钢材,委托某船运公司运往中国境内。一日,该船运公司一艘夹载着该船船员私自在国外购买的500多件电器等物的船,在中国海口市担杆岛附近海域进行走私交易时,被中国某海关抓获。该海关作出决定,将包括该贸易公司100吨钢材在内的船上所有
某事业单位2012年初准备使用财政性资金修缮一幢办公楼,预算金额为700万元,采用公开招标方式。经确认,此次采购项目已经达到公开招标的标准。该单位委托远大招标公司代理进行公开招标的事宜,已知远大公司是取得的政府采购代理机构资格的中介机构。2012
国内企业甲由外国投资者乙收购51%的股权于1999年10月8日依法变更为中外合资经营企业丙。经审批机关批准后,乙于2000年1月15日支付了购买股权总额50%的款项,于2000年3月20日支付了购买股权总金额20%的款项,于2000年10月5日支付了剩余
教学语言是教师进行化学教学时最常用的工具和手段,下列哪一项不是教学语言应具有的特点?()
如图所示,过正方体ABCD-A1B1C1D1的顶点A作直线l,使l与棱AB,AD,AA1所成的角都相等,这样的直线l可以作()
2015年国家自然科学基金委全年共接收173017项各类申请,同比增长约10%。择优资助各类项目40668项,比上年增加1579项,资助直接费用218.8亿元,平均资助强度(资助直接费用与资助项数的比值)53.8万元,各项工作取得新进展新成效。在研究项目
细胞核呈咖啡豆样外观见于
—Tellmesomethingaboutyouradventurelastyear.—Welostourwayintheforestand______mattersworsewas______itbegantora
最新回复
(
0
)