Search results
Results From The WOW.Com Content Network
The term polyphyly, or polyphyletic, derives from the two Ancient Greek words πολύς (polús) 'many, a lot of', and φῦλον (phûlon) 'genus, species', [8] [9] and refers to the fact that a polyphyletic group includes organisms (e.g., genera, species) arising from multiple ancestral sources.
The term monophyly, or monophyletic, derives from the two Ancient Greek words μόνος (mónos), meaning "alone, only, unique", and φῦλον (phûlon), meaning "genus, species", [4] [5] and refers to the fact that a monophyletic group includes organisms (e.g., genera, species) consisting of all the descendants of a unique common ancestor.
The term paraphyly, or paraphyletic, derives from the two Ancient Greek words παρά (pará), meaning "beside, near", and φῦλον (phûlon), meaning "genus, species", [2] [3] and refers to the situation in which one or several monophyletic subgroups of organisms (e.g., genera, species) are left apart from all other descendants of a unique common ancestor.
Different terms are used to describe prenatal development, meaning development before birth. A term with the same meaning is the "antepartum" (from Latin ante "before" and parere "to give birth") Sometimes "antepartum" is however used to denote the period between the 24th/26th week of gestational age until birth, for example in antepartum ...
Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 36 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus.
Physical development. Typically grows between 1 and 1.5 inches (2.5 and 3.8 cm) and gains about 2 pounds (910 g). [20] Motor development. Hands kept in tight fists. [21] Equal movement of arms and legs on both sides. [21] Able to briefly hold up head when in prone position. [21] Arm thrusts are jerky. [22] Brings hands close to eyes and mouth. [22]
An evolutionary grade is a group of species united by morphological or physiological traits, that has given rise to another group that has major differences from the ancestral group's condition, and is thus not considered part of the ancestral group, while still having enough similarities that we can group them under the same clade.
The embryophytes (/ ˈ ɛ m b r i ə ˌ f aɪ t s /) are a clade of plants, also known as Embryophyta (/ ˌ ɛ m b r i ˈ ɒ f ə t ə,-oʊ ˈ f aɪ t ə /) or land plants.They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands.