Definition Ethology, which is the comparative study of behavior from an evolutionary perspective, often deals with the drives relating to feeding, sex, care of young, etc. These drives are apparently motivations that spring from a disturbance in the internal equilibrium of an animal. They are modified factors either internal or present in the environment Read more about Ethology[…]

human chromosomes

Sex Determination

The genetic determinant of sex is located on the Y chromosome (Sex Determination) Examination of human chromosomes reveals a consistent difference between the sexes in karyotype (or pattern of chromosomal morphologies). Thus, the human has 46 chromosomes, 22 pairs of autosomes and one pair of sex chromosomes (Figure 1). Human females, and indeed all female Read more about Sex Determination[…]

steroid receptor

Reproductive Hormones

In this article, you will be introduced to many reproductive messengers, but here we focus on a few key hormones. We start with the sex steroid, which are the central players in reproduction. Here, a more detailed account of this family is given. The sex steroids These steroids make up a large group of molecules Read more about Reproductive Hormones[…]

Human reproductive system

Human Reproductive System

Human Reproductive System At the core of sexual reproduction lies the creation and fusion of the two types of gamete. the female oocyte. the male spermatozoon. Production of Gametes Their production occurs in distinctive female and male gonads: the ovary and testis. Male Reproductive Organ Thus, the human male develops obvious external genitalia and a Read more about Human Reproductive System[…]

biology questions with answer

17 Questions About Biology Which Help You Understand it

1. Are hypotheses always designed to be true assumptions of an actual state of affairs? Hypotheses are not designed to be true for all time. In fashioning a hypothesis, the scientist is aiming for operational truth, a “truth” that works as an explanation of the data but may be replaced as new data are found, Read more about 17 Questions About Biology Which Help You Understand it[…]

scientific method

Scientific Method

Definition of Science Science is an organized system for the systematic study of particular aspects of the natural world. Scope of Science The scope of science is limited to those things that can be apprehended the senses (sight, touch, hearing, etc.). Generally, science stresses an objective approach to the phenomena that are studied. Questions Read more about Scientific Method[…]

male reproductive system diagram

Male Reproductive System

The reproductive role of the human male is to produce sperm and deliver them to the vagina of the female. Structure of male reproductive system This function requires the following structures: Two testes that produce sperm and the male sex hormone, testosterone. Accessory glands and tubes that furnish a fluid for carrying the sperm to Read more about Male Reproductive System[…]

sexual reproduction

Sexual Reproduction

Sexual Reproduction in Invertebrates In sexual (L. sexualis, pertaining to sex) reproduction, the offspring have unique combinations of genes inherited from the two parents. Offspring of a sexual union are somewhat different from their parents and siblings—they have genetic diversity. Each new individual represents a combination of traits derived from two parents because syngamy, or Read more about Sexual Reproduction[…]