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Interspecific Competition Relationship - Competitive & Niche Differentiation

By: HWC, Views: 6323

In an environment with limited resources, any organisms that utilize the same resources will be in competition with each other. For example, let's look at two competing species of paramecium, a single-celled organism that feeds on bacteria. If we raise each of these species in isolation, both...

Female Reproductive System - Hormonal regulation (GnRH) الجهاز التناسلي للأنثى - التنظيم الهرموني

By: HWC, Views: 7092

• There is a complex interaction between the anterior pituitary gland, the hypothalamus, the ovaries and the uterus that leads to the monthly changes that women experience during their monthly reproductive cycle. • Two monthly cycles constitute these changes: • Ovarian cycle. • Uter...

Genetic distance between human groups

By: HWC, Views: 3542

One proposed family tree for modern humans. This family tree is based on nucleic-add hybridization studies of many genes and immuno-logical comparisons. Branch points show presumed genetic divergences. This data indicates that the greatest genetic distance separates humans native to Afri...

Fertilization and Development

By: HWC, Views: 7041

• Fertilization is the process by which the two gametes from the parents fuse their genetic material to form a new individual (zygote). • Fertilization requires that sperm cells swimming through the uterine tube contact a secondary oocyte. • Once sperm penetrate the secondary oocyte's ...

How proteins function? How do proteins work?

By: HWC, Views: 6282

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...

Introduction to Autism

By: Administrator, Views: 10064

Autism is a developmental disorder characterized by difficulties with social interaction and communication, and by restricted and repetitive behavior. Parents usually notice signs during the first three years of their child's life. These signs often develop gradually, though some children with au...

Membrane transport proteins - pores, gated channels and pumps

By: HWC, Views: 6758

• a Three different types of membrane ion transport proteins are required to produce and carry electrical signals: • Pores • Gated channels • Na+/ K+ pump • Pores are always open and allow the diffusion of Na+ and K+ ions across the membrane, down their concentration gradients...

Endocytosis - pinocytosis, receptor mediated and Transcytosis

By: HWC, Views: 6584

Pinocytosis is the process in which a cell "drinks" a tiny droplet Of extracellular fluid, including its solutes. Pinocytosis (Cell Drinking) is the process by which the cell takes in fluids (as well as any small molecules dissolved in those fluids). • The plasma membrane folds inward to...

Sperm Formation Animation

By: Administrator, Views: 370

A man’s reproductive system is specifically designed to produce, store, and transport sperm. Unlike the female genitalia, the male reproductive organs are on both the interior and the exterior of the pelvic cavity. They include: the testes (testicles) the duct system: epididymis and vas def...