<< Chapter < Page Chapter >> Page >

All the individuals of a species living within a specific area are collectively called a population    . For example, a forest may include many pine trees. All of these pine trees represent the population of pine trees in this forest. Different populations may live in the same specific area. For example, the forest with the pine trees includes populations of flowering plants and also insects and microbial populations. A community    is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the forest’s community. The forest itself is an ecosystem. An ecosystem    consists of all the living things in a particular area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain water. At the highest level of organization ( [link] ), the biosphere    is the collection of all ecosystems, and it represents the zones of life on earth. It includes land, water, and even the atmosphere to a certain extent.

Art connection

A flow chart shows the hierarchy of living organisms. From smallest to largest, this hierarchy includes: (1) Organelles, such as nuclei, that exist inside cells. (2) Cells, such as a red blood cell. (3) Tissues, such as human skin tissue. (4) Organs such as the stomach make up the human digestive system, an example of an organ system. (5) Organisms, populations, and communities. In a forest, each pine tree is an organism. Together, all the pine trees make up a population. All the plant and animal species in the forest comprise a community. (6) Ecosystems: the coastal ecosystem in the Southeastern United States includes living organisms and the environment in which they live. (7) The biosphere: encompasses all the ecosystems on Earth.
The biological levels of organization of living things are shown. From a single organelle to the entire biosphere, living organisms are parts of a highly structured hierarchy. (credit “organelles”: modification of work by Umberto Salvagnin; credit “cells”: modification of work by Bruce Wetzel, Harry Schaefer/ National Cancer Institute; credit “tissues”: modification of work by Kilbad; Fama Clamosa; Mikael Häggström; credit “organs”: modification of work by Mariana Ruiz Villareal; credit “organisms”: modification of work by "Crystal"/Flickr; credit “ecosystems”: modification of work by US Fish and Wildlife Service Headquarters; credit “biosphere”: modification of work by NASA)

Which of the following statements is false?

  1. Tissues exist within organs which exist within organ systems.
  2. Communities exist within populations which exist within ecosystems.
  3. Organelles exist within cells which exist within tissues.
  4. Communities exist within ecosystems which exist in the biosphere.

The diversity of life

The fact that biology, as a science, has such a broad scope has to do with the tremendous diversity of life on earth. The source of this diversity is evolution    , the process of gradual change during which new species arise from older species. Evolutionary biologists study the evolution of living things in everything from the microscopic world to ecosystems.

The evolution of various life forms on Earth can be summarized in a phylogenetic tree ( [link] ). A phylogenetic tree    is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both. A phylogenetic tree is composed of nodes and branches. The internal nodes represent ancestors and are points in evolution when, based on scientific evidence, an ancestor is thought to have diverged to form two new species. The length of each branch is proportional to the time elapsed since the split.

This phylogenetic tree shows that the three domains of life, bacteria, archaea and eukarya, all arose from a common ancestor.
This phylogenetic tree was constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms lacking intracellular organelles. (credit: Eric Gaba; NASA Astrobiology Institute)

Questions & Answers

Is there any other type of a eukaryotic cell.
Grace Reply
what is bionomial nomenclature
Rachaelda Reply
state the role of mitochondria
Rachaelda
mitochondria ia power House of the cell. it provides energy and as ATP. Cells energy currency.
Haider
The scientific method of giving short names on the basis of genius and species.
Haider
it is introduce by carlous Lennieus
Haider
it is naming of living organism where by they are given two names one generic and the other specific name
Kenneth
what is element
Kofi Reply
Structure of water molecule and it's biological significance. .....help guys
Ashly
what is the formula for chemical equetion
Justo Reply
Why mitochondria is called the power house of the congo the bahamas cell
Farrukh Reply
how can I learn this subject?
mascuud Reply
what's microscope?
Mathias Reply
A device used to study a very small specimen thst cannt br seen with the naked eyes for example cells, or microorganisms.
Danisha
a medical device used to study cells bacteria viruses and parasites e.g electron microscope for studying cells.
Grace
exactly microscope
Randa
is an instrument use to view microorganisms such as viruses and bacteria
Ohene
it is an instrument used to magnify micro-scopic organism
Kenneth
what does multi seminar mean
Grace Reply
many seminars
Grace
how many cells on the human
Amar Reply
how is genetic testing?
Nyabuoy
test
Nyuongatdet
which party of an internal leaf which represent organ and tissue
fernando
3 trilleons cells on the human
Jyoti
name the groups of bacteria, what they cause and explain the components of bacterial cell
Emmanuel
what are the three level of relationship that exist between organism?
Chinedu
trillions of cells
Grace
unicellular
Kenneth
who many cell are in the human body
Ayasso Reply
trillions of cells
Grace
what causes coloring of skin variation
Prince Reply
what is your answer
Jonathan Reply
which qn
Randa
what is chemosynthesis
Irene
who many cell are in the human body
Ayasso
there are billion cells in human body
fazeela
what are three stages of mitosis
jerry
they're alot cells in our body
jerry
what are the stages of mitosis
jerry
they are prophez methaphez anaphez. thelophez
fazeela
anyone to explain each of the following,, prophase, metaphase, anaphase and telophase
jerry
what is a filial
Mbah Reply
denoting the offspring of a cross
Grace
what is the difference between chlorophyll and photosynthesis
Rahman Reply
Chloe is the green pigment found in green plants while photosynthesis is the process by which plant produce their own food
mary
photosynthesis is the production of food by plant while chlorophyll is the green pigment that is found in chloroplast..
jerry
chrolophyll (green colouring matter in leaves) while photosynthesis (process by which green plants make their own food)
Nakhombi
What isaac life
Farrukh
chlorophyll is the pigment that gives a plant its green color while photosynthesis is when a plant makes it's own food.
Grace
photo meaning light and synthesis meaning to make
Grace
what are the functions of parts of microscope
Bami Reply
base to provide support
Ian
only base what about the other
Bami
has only one function
Mark
Mirror ... used to reflect light
Irene

Get the best Biology course in your pocket!





Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask