Fossil ghost ranges are most common in some of the oldest and some of the youngest strata.

نویسنده

  • M A Wills
چکیده

Biologists routinely compare inferences about the order of evolutionary branching (phylogeny) with the order in which groups appear in the fossil record (stratigraphy). Where they conflict, ghost ranges are inferred: intervals of geological time where a fossil lineage should exist, but for which there is no direct evidence. The presence of very numerous and/or extensive ghost ranges is often believed to imply spurious phylogenies or a misleadingly patchy fossil record, or both. It has usually been assumed that the frequency of ghost ranges should increase with the age of rocks. Previous studies measuring ghost ranges for whole trees in just a small number of temporal bins have found no significant increase with antiquity. This study uses a much higher resolution approach to investigate the gappiness implied by 1,000 animal and plant cladograms over 77 series and stages of the Phanerozoic. It demonstrates that ghost ranges are indeed relatively common in some of the oldest strata. Surprisingly, however, ghost ranges are also relatively common in some of the youngest, fossil-rich rocks. This pattern results from the interplay between several complex factors and is not a simple function of the completeness of the fossil record. The Early Palaeozoic record is likely to be less organismically and stratigraphically complete, and its fossils -- many of which are invertebrates-may be more difficult to analyse cladistically. The Late Cenozoic is subject to the pull of the Recent, but this accounts only partially for the increased gappiness in the younger strata.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Vascular Cryptogam Plants of the Khoshyeilagh Formation, Northern Shahrud, Eastern Alborz Ranges

Fragmentary, indifferently preserved, and of low diversity plant remains occur in basal part of the Khoshyeilagh Formation, northern Shahrud, eastern Alborz Ranges. The oldest hitherto reported from Iran, the remains are essentially assignable to lycophytes and psilophytes. Additionally, spores retrieved from the Khoshyeilagh Formation with reference to available data on spore-plant relation-sh...

متن کامل

بررسی فراوانی یافته‌های غیرطبیعی عکس ریه در بیماران مبتلا به سل ریوی در بیماران بستری شده در بیمارستان رسول اکرم(ص) و فیروزگر در طی سال‌های 81-1380)

    Tuberculosis has been one of the most important problems for a long time. This disease can involve different organs among which lung is the most common one. Chest X-ray is the oldest and the most practical diagnostic method for pulmonary tuberculosis. Using chest X-ray can cause difficulties for the students of medicine and young physicians because of the different patterns of lung involvem...

متن کامل

Molecular epidemiology of Human Papillomaviruses in breast cancer, Golestan province of Iran

Abstract Background and objectives: Breast cancer is the most prevalent one in women. Some of the common causative factors are genetic background, nutritional and environmental factors. Viruses are believed as a risk factor in this cancer, too. Recent studies reported that Human Papillomaviruses can be one of the possible risk factors of breast cancer. This study focused on investigation of the...

متن کامل

CONGESTIVE HEART FAILURE IN CHILDREN: A SURVEY OF 114 PATIENTS

During a period of four years between June, IS, 1988 to June, IS, 1992 one hundred and fourteen patients with congestive heart failure (CHF) were admitted to the pediatric department of Taleghani General Hospital. During the above period, 192 patients with heart disease were hospitalized at this department and CHF was the cause of admission in 59.4% of them. Congenital heart disease (CHO) w...

متن کامل

Assessments of applicability of Q and RMi systems in binary tunnels of Bakhtiari dam_ Iran

The main rock mass classification systems make use of similar rock mass parameters. Due to lack of comprehensive estimation systems, determining the real specifications of jointed rocks faces some difficulties. A vast number of parameters with various degrees of impact are involved in such definitions. Combination impact of all the effective parameters is to be figured out in order to come up w...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Proceedings. Biological sciences

دوره 274 1624  شماره 

صفحات  -

تاریخ انتشار 2007