After completing this chapter you will be able to:
- describe the nature of biological diversity and the biological species concept - outline some of the primary human-caused threats to Earth's biodiversity - explain the principles of taxonomy and phylogeny and the concepts of taxonomic rank - describe and compare traditional and modern biological classification systems - outline some of the key features used to classify all living organisms into six kingdoms - construct and apply dichotomous keys for the purpose of identifying species - use appropriate sampling methods to collect specimens from an ecosystem and classify them using scientific criteria
What Connects Life on Earth?
Life can be found almost everywhere. Organisms live at the bottom of the ocean abyss, deep underground, on icy mountaintops, and in boiling hot springs. Even our own bodies are home to countless microscopic organisms—we are their habitat!
Emperor penguins show many of the most dramatic and fascinating qualities of living things, such as the ability to live and flourish in extreme environments. Emperor penguins begin life by hatching from an egg during sunless days on a sheet of ice in the most inhospitable continent on Earth—Antarctica. Surviving temperatures of –60 °C, they are cared for and protected by their parents until they are able to march for tens of kilometres to the water's edge. As they plunge into the icy water, they transform from awkward waddlers into majestic, high-performance swimming machines, faster and more agile than almost any fish!
As unique and marvellous as penguins are, they are just one of the millions of remarkable organisms on Earth. Our planet is also home to elephants with noses that drag on the ground, albatrosses that can stay airborne for more than a year at a time, and deadly poisonous stonefish hiding in coral reefs. Some eastern white cedar trees in Ontario are over 1000 years old!
The diversity of life is truly extraordinary. It is also immeasurably valuable. All organisms depend on other organisms for survival. Organisms provide us with oxygen, clean air and water, food, medicines, and building materials.
Some organisms are extremely numerous, and others are quite rare. In Ontario, mosquito and black fly populations naturally number in the billions. In contrast, populations of the eastern mountain lion and prickly pear cactus have probably always been relatively low. But throughout the world, native plant and animal populations are declining due to habitat loss, pollution, over-harvesting, and competition with invasive species. Many species are threatened with extinction.
In this chapter you will examine the grandeur of life, beginning with an exploration of the diversity of life and our dependence on it. You will learn how organisms are identified and classified, and gain insights into why scientists are so concerned about the threats to the diversity of life.
STARTING POINTS
Answer the following questions using your current knowledge. You will have a chance to revisit these questions later, applying concepts and skills from the chapter.
1. How many different kinds of living things do you think there are on Earth? How might this diversity be important or valuable?
2. How do you think organisms can be distinguished from one another?
3. What do you think are the benefits of naming and classifying (or grouping) living things? How might this be accomplished?
Print Page 7
Mini Investigation
Identify the Extremes of Life
Skills: Questioning, Predicting, Communicating
SKILLS HANDBOOK A2.1
A good way to begin a study of the diversity of life on Earth is to consider the great variety of organisms that you are already familiar with. In this activity you will brainstorm examples of living things that fall into given categories and suggest some categories of your own.
1. Brainstorm examples of organisms on Earth that you think best fit the following categories: - largest living animal - most beautiful organism - smallest plant - most valuable food - most unusual animal - most powerful predator - most colourful animal - most dangerous organism - most valuable fungus - fastest flyer - fastest swimmer - three more categories of your own choosing
You may list more than one kind of organism for each category, but you must identify which of these you think is the "best" choice.
2. Record your choices in a table or other suitable format.
3. Have a class discussion in which groups argue in favour of their selections. Be prepared to change your mind if others have a better case for their choice.
A. Which categories are based on opinion, and which are based on an objective characteristic?
B. Did everyone interpret the categories in the same way? Did "valuable" or "dangerous" have the same meaning for everyone?
C. Were there any choices that almost everyone agreed with? Why do you think that was the case?
KEY CONCEPTS
After completing this chapter you will be able to:
- describe the nature of biological diversity and the biological species concept
- outline some of the primary human-caused threats to Earth's biodiversity
- explain the principles of taxonomy and phylogeny and the concepts of taxonomic rank
- describe and compare traditional and modern biological classification systems
- outline some of the key features used to classify all living organisms into six kingdoms
- construct and apply dichotomous keys for the purpose of identifying species
- use appropriate sampling methods to collect specimens from an ecosystem and classify them using scientific criteria
What Connects Life on Earth?
Life can be found almost everywhere. Organisms live at the bottom of the ocean abyss, deep underground, on icy mountaintops, and in boiling hot springs. Even our own bodies are home to countless microscopic organisms—we are their habitat!
Emperor penguins show many of the most dramatic and fascinating qualities of living things, such as the ability to live and flourish in extreme environments. Emperor penguins begin life by hatching from an egg during sunless days on a sheet of ice in the most inhospitable continent on Earth—Antarctica. Surviving temperatures of –60 °C, they are cared for and protected by their parents until they are able to march for tens of kilometres to the water's edge. As they plunge into the icy water, they transform from awkward waddlers into majestic, high-performance swimming machines, faster and more agile than almost any fish!
As unique and marvellous as penguins are, they are just one of the millions of remarkable organisms on Earth. Our planet is also home to elephants with noses that drag on the ground, albatrosses that can stay airborne for more than a year at a time, and deadly poisonous stonefish hiding in coral reefs. Some eastern white cedar trees in Ontario are over 1000 years old!
The diversity of life is truly extraordinary. It is also immeasurably valuable. All organisms depend on other organisms for survival. Organisms provide us with oxygen, clean air and water, food, medicines, and building materials.
Some organisms are extremely numerous, and others are quite rare. In Ontario, mosquito and black fly populations naturally number in the billions. In contrast, populations of the eastern mountain lion and prickly pear cactus have probably always been relatively low. But throughout the world, native plant and animal populations are declining due to habitat loss, pollution, over-harvesting, and competition with invasive species. Many species are threatened with extinction.
In this chapter you will examine the grandeur of life, beginning with an exploration of the diversity of life and our dependence on it. You will learn how organisms are identified and classified, and gain insights into why scientists are so concerned about the threats to the diversity of life.
STARTING POINTS
Answer the following questions using your current knowledge. You will have a chance to revisit these questions later, applying concepts and skills from the chapter.
1. How many different kinds of living things do you think there are on Earth? How might this diversity be important or valuable?
2. How do you think organisms can be distinguished from one another?
3. What do you think are the benefits of naming and classifying (or grouping) living things? How might this be accomplished?
Print Page 7
Mini Investigation
Identify the Extremes of Life
Skills: Questioning, Predicting, Communicating
SKILLS HANDBOOK A2.1
A good way to begin a study of the diversity of life on Earth is to consider the great variety of organisms that you are already familiar with. In this activity you will brainstorm examples of living things that fall into given categories and suggest some categories of your own.
1. Brainstorm examples of organisms on Earth that you think best fit the following categories:
- largest living animal
- most beautiful organism
- smallest plant
- most valuable food
- most unusual animal
- most powerful predator
- most colourful animal
- most dangerous organism
- most valuable fungus
- fastest flyer
- fastest swimmer
- three more categories of your own choosing
You may list more than one kind of organism for each category, but you must identify which of these you think is the "best" choice.
2. Record your choices in a table or other suitable format.
3. Have a class discussion in which groups argue in favour of their selections. Be prepared to change your mind if others have a better case for their choice.
A. Which categories are based on opinion, and which are based on an objective characteristic?
B. Did everyone interpret the categories in the same way? Did "valuable" or "dangerous" have the same meaning for everyone?
C. Were there any choices that almost everyone agreed with? Why do you think that was the case?