DISSERTATION RESEARCH: Key Adaptations: Morphological Specializations Creating Ecological Specialization or Ecological Generalization?

加州大学伯克利分校的安东尼·巴诺斯基博士和罗伯特·费拉内克先生获得了一笔资助，研究古代哺乳动物特殊特征的进化（所谓的关键适应）是否会导致生态专业化或普遍化。研究的形态特化是有蹄类哺乳动物高冠牙齿的进化，这被认为是导致在新进化的草原上特化进食的关键适应。 本研究分析了马、骆驼和牛家族中与饮食和栖息地占用相关的形态学。 用于确定饮食的主要方法是分析牙釉质中发现的稳定碳同位素值。 这种饮食代理表明哺乳动物是否专注于以草或树木和灌木为食。 栖息地的占用是通过确定动物出现的化石地点的数量和位置来解决的。 这项研究的目的是分析三个时间段的有蹄哺乳动物的饮食和栖息地占用，超过700万年前，10，000 - 30，000年前和现代有蹄哺乳动物。 这项研究跨越了近2000万年的哺乳动物进化，并在分析中纳入了形态学，饮食和栖息地使用。这项拟议的研究将测试初步结果，表明高冠牙齿的进化使哺乳动物变得更加普遍，这与目前的假设不同。这项研究很重要，因为它揭示了近2000万年来有蹄哺乳动物进化过程中20多种哺乳动物的生态学。它还提供了知识，现代有蹄类哺乳动物是否出现在特定的生态系统中，因为它们专门用于狭义的生态位，或者如果它们目前占据生态系统，因为偏好，竞争，甚至机会等原因。这项研究还为同位素在哺乳动物古生物学中的应用提供了新的教学工具和研究应用。

A grant has been awarded to Dr. Anthony Barnosky and Mr. Robert Feranec at the University of California at Berkeley to study whether the evolution of specialized features in ancient mammals, so-called key adaptations, causes ecological specialization or generalization. The morphological specialization to be studied is evolution of high-crowned teeth in hoofed mammals, which has been regarded as a key adaptation that led to specialized feeding on newly evolved grasslands. This study analyzes morphology relative to diet and habitat occupation in the horse, camel, and cow families. The main method used to determine diet is analysis of stable carbon isotope values found in tooth enamel. This proxy for diet indicates whether mammals focused feeding on grasses or on trees and shrubs. Habitat occupation is resolved by determining the number and location of fossil sites in which the animals occurred. The goal of this study is to analyze the diet and habitat occupation of hoofed mammals at three time periods, older than 7 million years ago, between 10,000-30,000 years ago, and modern hoofed mammals. This research spans almost 20 million years of mammal evolution, and incorporates morphology, diet, and habitat use in the analysis. This proposed study will test preliminary results that suggest evolution of high-crowned teeth allows mammals to become more generalized, which differs from current hypotheses. The study is important because it sheds light on the ecology of more than 20 genera of mammals through nearly 20 million years of hoofed-mammal evolution. It also provides the knowledge of whether modern hoofed mammals occur in particular ecosystems because they are specialized for narrowly defined niches, or if they currently occupy the ecosystem because of reasons like preference, competition, or even chance. The study also contributes new teaching tools and research applications for the uses of isotopes to mammal paleontology.