Unit 1

1. Unit 1 Chapter 1 – Biologists in the 21st Century

2. Biologists Study Living Things. • Biology is the field of science that studies living things and how they interact with each other and their environment..

3. Specialized Areas of Biology Include: Anatomy- the physical structure of humans and animals Botany- the structure and function of plants Cytology-the structure and function of cells Ecology- the relationship among organisms and their environment. Genetics- study of heredity Microbiology-study of microscopic organisms. Physiology- study of the function of organs and organ systems. Taxonomy- the scientific classification of organisms. Zoology- the structure and function of animals

4. Earth is home to an incredible diversity of life. • Living things are found about everywhere on Earth. • Living things come in a fantastic range of sizes and adaptations to help them survive. • They range from submicroscopic viruses and bacteria to giant redwoods and blue whales.

5. BIOSPHERE • Consists of all the livings things and all the places they are found on Earth. • Thus, the biosphere consists of all the places where life is possible on the planet.

6. BIODIVERSITY • The variety of life in a particular area • Tends to . . . • increase as you move towards the equator and • decrease as you move towards the poles. • The more stable an environment is the more diverse it tends to become over time.

7. BIODIVERSITY • Bacteria are the oldest type of living organism on earth. Evidence of bacteria extends back at least 3.5 billion years. These early microbes filled Earth's atmosphere with oxygen over millions of years, allowing oxygen-breathing life to exist. • Even though each bacterium weighs less than a quadrillionth of a gram, the weight of all bacteria in the world is roughly one billion tons (a gigaton). This is about equal to the weight of all plants on Earth.  In other words, the biomass, or mass of living organisms, of bacteria roughly equals the weight of 50 million blue whales (200 tons or 400,000 lbs/whale).

8. Levels of Organization for Living Things So how are living things organized as compared to each other and the environment?

9. Like a set of nesting dolls… Levels of Organization for Living Things • We can think of organisms and how they interact with each other and their environment by arranging them into ever larger groups. This is called the . . . Organism(smallest) Species Population Community Ecosystem Biome Biosphere(largest)

10. Levels of Organization for Living Things • An organism consists of one single individual, a single living thing. • Example: A single pigeon • A speciesis an interbreeding population of organisms that can produce healthy, fertile off-spring. • includes only one type of organism. • Example: the Rock Pigeon • A population includes all members of one species that live in the same area. • Example: all the Rock Pigeons in Kansas City

11. So what characterizes a living thing? How do you know when something is living or not?

12. All Organisms Share Certain Characteristics • All living things are made of one or more cells. • A cell is the basic unit of life.

13. Cells cont. . . • Microscopic single-celled organisms are the most common forms of life on Earth.

14. Cells cont. . . • Larger organisms that you can see with your eyes are made of more than one cell, and are called multicellular.

15. All Organisms Share Certain Characteristics • A living things need energy. • Energy is the ability to cause change or do work. • Living things use chemical energy to power their cells. • Energy powers the processes of metabolism • All the chemical processes that build up or break down materials.

16. All Organisms Share Certain Characteristics • A living things respond to the environment. • All organisms must be able to react to their environment in order to survive.

17. This could be a quick individual response: Stimulus and Response Living things respond to changes in their environment when they . . . • seek food, • avoid danger, • seek favorable, environment, • seek like individuals, etc.

18. Or this could be a long term multigenerational response in a population due to Natural Selection and Evolution. • Evolutionis the change that populations of organisms display over many generations (long periods of time). • Explains how many different kinds of organisms have come into existence. • Explains how modern • organisms are related to • those that lived in the past.

19. Respond cont. . . • Natural Selection Organisms that have certain favorable traits are better suited to survive and reproduce than those organisms that don’t have favorable traits • Natural selection is the driving force for evolutionary changes in a population

20. All Organisms Share Certain Characteristics • All living things reproduce and develop. • Produce new individuals • Pass on their genetic information to their offspring. • Genetic material = DNA (deoxyribonucleic acid) RNA (ribonucleic acid) rarely • The process of development allows organisms to mature and gain the ability to reproduce.

21. Several themes connect concepts from many fields of biology Systems Structures & Functions Maintain Homeostasis Evolution Explains Diversity & Unity.

22. 1. All levels of life have systems of related parts. • A system is an organized group of related parts that interact to form a whole. • Can exist at the very small (molecular) scale to as large as the entire biosphere. • An ecosystem is a biological system comprising of living and nonliving parts. • the community of living things in an environment and the non-living things that support them.

23. 2. Structure and function are related in biology Living things are very complex compared to non-living things. The design of the structures that organisms have helps them survive in their environment. The eagle has structures (wings) that allow it to fly through the air. Penguins use their “wings” to swim or fly under water.

24. 3. Organisms maintain homeostasis to survive in diverse environments. • All organisms must maintain stable internal conditions in order to survive (temperature, water content, chemical content etc.) • HOMEOSTASIS- is the state that cells (organisms) maintain by self-regulating activities (like sweating when you are hot).

25. 4. Evolution explains the unity and diversity of life. • Evolution is the change in living things over time. • The change in the genetic makeup of a population or species. • A long term process, multigenerational. • An inherited trait that gives an advantage to an individual and passed to future generations is an adaptation.

26. An inherited trait that gives an advantage to an individual and passed to future generations is an adaptation. • Natural Selection predicts those with the adaptations which give advantages will tend to survive and reproduce more. • Over time the makeup of the population changes • Different populations may develop, those with and those without the new adaptations • This can lead to diversification and speciation. • Speciation requires reproductive isolation • Speciation is the when one species changes over time into two or more species.