Question

Choose one of the following concepts related to life sciences and explain, with concrete examples, how what you learned about it and has changed your personal understanding. (200-300 words)

• Biodiversity
• Cell Structure and Function
• Homeostasis

Answer 1

Biodiversity : It is the variety of all life within a geographic region or often the total variety of life on earth . according to some biologists 'biodiversity is the totality of gene, species and ecosystem of a region' . biodiversity is of three types -species diversity, genetic diversity(variety in species due to genetic variation e.g -color variety of maize ) , habitat diversity(variety due to different habitat e.g - land species-african lion , asiatic lion , aquatic spercies-marine species ,fresh water species) . species diversity  is measured by counting the species number i.e the species richness in an area .

for example Indian biodiversity consists of near about 150000  species . there are 1230+ bird species in which 60 species are endemic( found only in some  paricular region, limited to area due to environmental condition .e.g - bicolored frog is endemic to western ghats of india . ) approx 400 mammals (44 endemic ) . 450 reptilia, 240 amphibia , 70000 arthropoda , 2500+ pisces . and thousands of plant species variety .

biodiversity depends on the temperature,climate, water resources, food resources, precipitation like natural factors as well as genetic variation ,mutation ,evolution like factors . maximum biodiversity is found in tropical region and coral reefs . terrestrial biodiversity is almost 20-25 times greater than ocean biodiversity .

the places where the number of species is high including endemic species , is known as hotspot , there are 18 hotspots in the world .

cell structure and function : Cell is the structural, functional and biological unit of life. All organism contains cell either one (in case of unicellular) and more ( in case of multicellular ). usually cells are of two types prokaryotes( pro means primitive and karyon means nucleus i.e the cells possesing primitive nucleus ) and eukaryotes (eu means ideal hence the cells possing ideal nucleus are known as eukayotes )

basically cells are consist of ptotoplasm i.e cytoplasm + nucleus/genetic material and a membrane.

cell membrane or cell wall : protoplasm of the cell is covered by cell membrane(eg-animal cell) or cell wall or both(plant cell ) .very few organism are present which are not posses any membrane or wall

cytoplasm: cells are consists of a semi solid matrix in which nucleus and cell organelle are present ,.in cytoplasm mitochondria , plastid , golgi body , desmosome , endoplasmic reticulam, ribosome , lysozomes are present and do their functions .

nucleus : eukaryotes posses ideal nucleus (containing nuclear envelop, nucleoplasm, nuclear chromatin ,nucleolus ) and prokaryotes posses incomplete nucleus (without nuclear envelop , nucleoplasm -naked genetic material.) Nucleas controles all cellular function and carries genetic material .

function : a cell can function as an organism itself . cellular digestion, cellular respiration, cellular excretion are the major functions of the cells .

Homeostasis : Greek Homoios means similar and stasis means standing still .i.e meaning of homeostasis is staying the same  It is a biological, self regulating process to maintain internal stability, physical and chemical balance of the body . it is the method of adjusting the internal condition which are optimal for life despite the external condition . it is the part of dynamic equilibrium tends to reach a steady state . homeostasis is the summery of coordination of all the body system especially nervous system , endocrine system and feedback mechanism . (homeostasis occurs in receptor - control center -effector pathway )

The control of body temperature ( optimum  internal temperature of human body is 37 degree celcius .the body always control this fixed temperature either generating heat or releasing extra heat )  , control of acid -base balance 9 body always maintain fixed p^H level ) , maintaining water amount, maintaining blood sugar level , maintaining blood pressure ( body always try to maintain fixed blood pressure by adjusting the diameter of the blood vessels and the pumping rate of the heart .) are the examples of biological homeostasis . it is extremely important  for survival of an organism.