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
Single mums are better at raising their kids than two parents—at least in the bird world. Mother zebra finches have to work hard
Single mums are better at raising their kids than two parents—at least in the bird world. Mother zebra finches have to work hard
admin
2013-01-20
35
问题
Single mums are better at raising their kids than two parents—at least in the bird world. Mother zebra finches have to work harder and raise fewer chicks on their own, but they also produce more attractive sons who are more likely to get a mate.
The finding shows that family conflict is as important an evolutionary driving force as ecological factors such as hunting and food supply. With two parents around, there’s always a conflict of interests, which can have a detrimental effect on the quality of the offspring.
In evolutionary terms, the best strategy for any parent in the animal world is to find someone else to care for their offspring, so they can concentrate on breeding again. So it’s normal for parents to try to pass the buck to each other. But Ian Hartley from the University of Lancaster and his team wondered how families solve this conflict, and how the conflict itself affects the offspring.
To find out, they measured how much effort zebra finch parents put into raising their babies. They compared single females with pairs, by monitoring the amount of food each parent collected, and removing or adding chicks so that each pair of birds was raising four chicks, and each single mum had two—supposedly the same amount of work.
But single mums, they found, put in about 25 per cent more effort than females rearing with their mate. To avoid being exploited, mothers with a partner hold back from working too hard if the rather is being lazy, and it’s the chicks that pay the price. "The offspring suffer some of the cost of this conflict," says Hartley.
The cost does not show in any obvious decrease in size or weight, but in how attractive they arc to the opposite sex. When the chicks were mature, the researchers tested the "fitness" of the male offspring by offering females their choice of partner. Those males reared by single mums were chosen more often than those from two-parent families.
Sexual conflict has long been thought to affect the quality of care given to offspring, says zoologist Rebecca Kilner at Cambridge University, who works on conflict of parents in birds. "But the experimental evidence is not great. The breakthrough here is showing it empirically."
More surprising, says Kilner, is Hartley’s statement that conflict may be a strong influence on the evolution of behaviour, clutch size and even appearance. "People have not really made that link," says Hartley. A female’s reproductive strategy is usually thought to be affected by hunting and food supply. Kilner says conflict of parents should now be taken into account as well.
What is the relationship between paragraph 4 and paragraph 5?
选项
A、Cause and effect.
B、Experiment and result.
C、Problem and solution.
D、topic and comment.
答案
B
解析
第四段是关于斑胸草雀单亲家庭和双亲家庭如何照顾后代的实验;第五段是依据实验所观察到的结果。所以,它们的关系是实验与结果。
转载请注明原文地址:https://kaotiyun.com/show/Y42O777K
0
考博英语
相关试题推荐
Outputisnowsixtimesitwasbeforeliberation.
Hereadthestory______foreverybodypresenttohear.
Theirconfidenceinhimwasgreatly_____byhisprolongedhesitationbeforetakinganyaction.
Concernedpeoplewantto_____theriskofdevelopingcancer.
Therearesomeearthphenomenayoucancounton,butthemagneticfield,somedayisnotofthem.Itfluctuatesinstrength,drif
Inmanycountriestobaccoandmedicinearegovernment_____.
FirsttherewasaWashingtonPostarticlepublishedshortlyaftertheelectionsonthepresumptivenewHousespeaker,"MutedTon
Heseemedreluctanttosendhistroopsinanefforttodiscouragethe_____peasants.
Thesportofwrestlingtests_____,strength,andstamina.
Manynetworkmembershadexpressedaninterestinthemerger,asitwillnotonlystrengthenthenetworkbutalsohelpto______
随机试题
格形钢板桩结构的格形墙体前板桩的设计入土深度,对于中密砂土地基不应小于()m,且不宜大于()m。
工程项目施工合同以付款方式划分为:①总价合同②单价合同③成本加酬金合同三种,以业主所承担的风险从小到大的顺序来排列,应该是()。
根据我国《造价工程师注册管理办法》的规定,造价工程师变更工作单位后,应当在规定期限内办理变更注册手续,而在办理变更注册手续后的一定期限内再次申请变更的,注册机构将不予办理。这两个期限分别为()。
水利水电施工组织设计文件中综合加工厂是由()组成。
赵某系港口区岳谷中心村村民。因所住房屋已破旧不堪拟大修,遂向区规划局提出申请要求批准其翻修房屋。区规划局作出不予批准决定。赵某遂向市规划局申请复议。市规划局作出维持区规划局不予批准决定的复议决定。赵某遂向区法院起诉,请求法院判决确认区规划局的不作为行为违法
甲公司2014年1月1日购入面值总额为100万元。票面年利率为4%的A债券,取得时的价款为104万元(含已到付息期但尚未领取的利息4万元),另支付交易费用0.2万元。甲公司将该项金融资产划分为交易性金融资产。2014年1月5日,收到购买时价款中所含的利息4
项目质量控制复核是指在出具报告前,对项目组作出的重大判断和在准备报告时形成的结论作出客观评价的过程,以下对项目质量控制复核的表述不恰当的是()。
下列关于新能源的说法,错误的是()。
下列选项中,原告可以申请法院先予执行的有()。
Hewentonfoot,buthe______bybus.
最新回复
(
0
)