sentence: All degrees exist in birds and mammals.
sentences_before: The opposite developmental strategy is called altricial, where the young are born or hatched helpless. These two categories are at ends of a continuum.
sentences_after: With the tiny eggs of invertebrates, different strategies have evolved. Many use some kind of metamorphosis, in which different stages of growth occupy different environmental niches.
concept_name: degree
headings: Precocial
categories: Developmental biology Birds Mammals