How innovations such as vision, flight and pregnancy evolve is a central question in
evolutionary biology. Examination of transitional (intermediate) forms of these traits can help …

Reproducing sharks must provide their offspring with an adequate supply of nutrients to
complete embryonic development. In oviparous (egg-laying) sharks, offspring develop …

Vertebrates that incubate embryos on or within the body cavity exhibit diverse strategies to
provide nutrients to develo** embryos, ranging from lecithotrophy (solely yolk-provided …

In brief Seahorses exhibit male pregnancy and are thus valuable comparative models for the
study of the physiology and evolution of pregnancy. This study shows that protein is …

The environment is a major contributor to phenotypic variation within natural populations.
Almost every organism has some aspect of its phenotype that is influenced by the …

Nutritional and metabolic cues are integral to animal development. Organisms use them
both as sustenance and environmental indicators, fueling, informing and influencing …

In human pregnancy, recognition of an embryo within the uterus is essential to support the
fetus through gestation. In most marsupials, such as the opossums, pregnancy is shorter …

Maternal provisioning and the developmental environment are fundamental determinants of
offspring traits, particularly in oviparous species. However, the extent to which embryonic …

Introduction Viviparity (live-birth) has evolved from oviparity (egg-laying) multiple times in
sharks. While most transitions from oviparity to viviparity have resulted in non-placental …

Evolution is the single unifying principle of biology and core to everything in the life
sciences. More than a century of work by scientists from across the biological spectrum has …