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Watch this video to see how plants respond to a stimulus—from opening to light, to wrapping a tendril around a branch, to capturing prey.

Reproduction

Single-celled organisms reproduce by first duplicating their DNA, and then dividing it equally as the cell prepares to divide to form two new cells. Multicellular organisms often produce specialized reproductive germline cells that will form new individuals. When reproduction occurs, genes containing DNA are passed along to an organism’s offspring. These genes ensure that the offspring will belong to the same species and will have similar characteristics, such as size and shape.

Growth and development

Organisms grow and develop following specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species’ young ( [link] ) will grow up to exhibit many of the same characteristics as its parents.

A photograph depicts a mother cat nursing three kittens: one has an orange and white tabby coat, another is black with a white foot, while the third has a black and white tabby coat.
Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Rocky Mountain Feline Rescue)

Regulation

Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Two examples of internal functions regulated in an organism are nutrient transport and blood flow. Organs (groups of tissues working together) perform specific functions, such as carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.

Homeostasis

A photos shows a white, furry polar bear.
Polar bears ( Ursus maritimus ) and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat under their skin. (credit: “longhorndave”/Flickr)

In order to function properly, cells need to have appropriate conditions such as proper temperature, pH, and appropriate concentration of diverse chemicals. These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through homeostasis    (literally, “steady state”)—the ability of an organism to maintain constant internal conditions. For example, an organism needs to regulate body temperature through a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear ( [link] ), have body structures that help them withstand low temperatures and conserve body heat. Structures that aid in this type of insulation include fur, feathers, blubber, and fat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.

Energy processing

Photo shows a California condor in flight with a tag on its wing.
The California condor ( Gymnogyps californianus ) uses chemical energy derived from food to power flight. California condors are an endangered species; this bird has a wing tag that helps biologists identify the individual. (credit: Pacific Southwest Region U.S. Fish and Wildlife Service)

Questions & Answers

which virus get affective in our body
nosheen Reply
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nosheen Reply
what is meant by virus
nosheen
virus are autonomous biomolecular system
Neuron
systems
Neuron
what are spermatophytes?
Nokuzola Reply
Explain the history of biology
Emmanuel Reply
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nosheen
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nosheen
what is legmaty
Akhabue Reply
what is the meaning Legimaty
Akhabue
what is the meaning Legimaty
Akhabue
what are herbivore, carnivore and omnivores animals
Aminu Reply
structure and functions of mitochondrion and lysosome
Iyao Reply
we have rough and smooth mitochondria
Paul
what is the meaning of biological catalyst?
Benjamin Reply
what is a syntific name of mopani tree
Sitabi Reply
What is the function of cell
Bello Reply
Rebuilt worn out tissues
Eze
Wat is the function of cell?
Belbon Reply
what is the name of the organelle responsible for heredity
Adelokun Reply
What's the main function of the CELL
Victor Reply
what is the main function of the cell
Hope
Is the smallest unit of an living things
Chanda Reply
Okay
Jason
What is a cell
Jason Reply
A cell is the basic unit of life.
Bernard
toads and frogs
Nelson

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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