Mission to Mars Day 4. Defining Life

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Amber Nelson
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1 Mission to Mars Day 4 Defining Life

2 Remember this quote? Mark Watney: If the oxygenator breaks down, I'll suffocate. If the water reclaimer breaks down, I'll die of thirst. If the hab breaches, I'll just kind of implode. If none of those things happen, I'll eventually run out of food and starve to death. We have some idea of what we need to do keep us alive but how do we know if something is alive to start with?

3 If you went to Mars the Viking Lander did! The primary mission objectives were to obtain high resolution images of the Martian surface, characterize the structure and composition of the atmosphere and surface, and search for evidence of life. If you went to Mars as an explorer, and your purpose was to find life how would you know what to look for? Make a list of criteria with your group right now of what identifies life you will share these ideas in a few minutes From these shared ideas, we will make a class definition of life.

4 What is life? (the Characteristics of Life) You are about to get a list of 8 characteristics that scientists have found that help to define life (on Earth) Remember to keep an open mind although these define life on earth, do these define life everywhere?

5 1. Made up of one or more cells Unicellular (onecelled) - ex. bacteria multicellular (manycelled) - ex. animals, plants

6 2. Use energy to survive autotroph makes its own food using energy from sun heterotroph gets energy by consuming other organisms

For example: If the plant sense the dragonfly, it will snap close, if the

7 3. Respond to stimuli in their environment Stimuli - factors in the environment that living things react to Response the reaction to something For example: If the plant sense the dragonfly, it will snap close, if the man touches a hot pan, he lets go. More ex: light, hunger, temperature, sound, fear

8 4. All living things reproduce sexual - two parents required (sperm and egg) asexual - only one parent cell is needed

9 5. Grow and Develop Each cell divides to make new cells (cell division) results in growth Some cells become specialized and perform different jobs than others (differentiation)

6. Maintain homeostasis Homeostasis a term that is used to both describe the survival of organisms in an ecosystem and to describe the successful survival of cells inside of an organism.

10 6. Maintain homeostasis Homeostasis a term that is used to both describe the survival of organisms in an ecosystem and to describe the successful survival of cells inside of an organism. a relatively stable internal environment (within a certain range) - (ex. Human body temperature is about 98.6 o F) If you get too cold what happens? What if you are too warm? Homeostasis video

11 7. Have a universal genetic code All living things have DNA (or RNA) DNA Deoxyribonucleic acid RNA RibonucleicAcid (left) Both of these are ways to carry genetic information DNA passes on genetic information from one generation to the next

12 8. Adapt and change over time to better survive Evolution - gradual change in a population of organisms over time Individuals DO NOT evolve

13 Brain Break! How Life Began Theory video Now, let s go back to the idea of what is life the very basic form of life is what?

14 All living things are made of cells A cell is the simplest structure of living things If an organism is unicellular, all functions of life happen within that one cell. If an organism is multicellular, the different cells have different jobs and they all work together

15 Simple Organisms Some organisms are simple: they are not particularly specialized and complicated in structure (think microscopic) These cells are organisms that function independently For example: Bacteria, Archaea, most protists (unicellular)

16 Complex Organisms Some organisms are more complex: Complex means that different parts of the organism performs different functions. Examples: humans, dogs, fish, mushrooms, oak trees, etc.

17 Organization in a complex organism: Structure and function work together Structure is the way something is made, function is the job it performs Structures join together to form systems Systems have specific functions due to the interactions between the parts At each level of structure, the interaction among the systems become more complex and more functions become possible

18 Complex organization order Cells form tissue Tissue made of similar cells doing a single job Organ different kinds of tissues that work together Organ system a group of organs working together Complex organism Then remember that this single organism is part of a population, community, ecosystem and biome!

19 Growth of an organism How do living things grow? Organisms grow by adding (making) more cells, not by increasing the size of their cells

20 What do cells look like? The word cell is Latin for small room They look as varied as the organisms they build (make up) Red Blood cell Stem Cell Brain cell Plant cell

21 Cells have structure and function Within the cell, there are parts that each have jobs or functions These parts or structures are called organelles Examples of organelles:

He looked at cork (a plant) under the microscope (30x) 2.

22 The microscope led to the discovery of cells A Robert Hooke published a book that described the cell 1. He looked at cork (a plant) under the microscope (30x) 2. He noticed little compartments, which he named cells because they resembled the little rooms that monks lived in

B. 1675 Anton Van Leeuwenhoek is considered the father of microscopy because of the advances he made in microscope design and use. 1. He looked at pond water under the microscope (300x) and noticed that the water was full of moving living things 2.

23 B Anton Van Leeuwenhoek is considered the father of microscopy because of the advances he made in microscope design and use. 1. He looked at pond water under the microscope (300x) and noticed that the water was full of moving living things 2. He made the most advanced microscope of his time

24 The Cell Theory was created! With the invention of the microscope and the contributions of many scientists, a very important question was answered in the 1850 s. The question was: Where do cells come from? the answer? Cell Theory

Forward Thinkers The Cell Theory was developed from three German scientist's discoveries.

In 1838 the German Botanist Matthias Schleiden discovered that all plants were composed of

Then only a year later a German zoologist, Theodor Schwann, discovered that all animals

25 Forward Thinkers The Cell Theory was developed from three German scientist's discoveries. They are Matthias Schleiden, Theodor Schwann, and Rudolph Virchow. In 1838 the German Botanist Matthias Schleiden discovered that all plants were composed of cells. Then only a year later a German zoologist, Theodor Schwann, discovered that all animals were composed of cells. Later in 1855 a German physician named Rudolph Virchow was doing experiments with diseases when he found that all cells come from other existing cells. Schleiden Schwann Virchow

26 Cell Theory There are 3 main concepts: 1. All living things are composed of cells 2. Cells come from other (pre-existing) cells 3. Cells are the basic structure of living things

27 More has been added: The modern version of the Cell Theory includes the ideas that: Energy flow occurs within cells. Heredity information (DNA) is passed on from cell to cell. All cells have the same basic chemical composition.

6.12A: You will understand that all organisms are composed of one or more cells.

TEKS: 6.12A, B 6.12A: You will understand that all organisms are composed of one or more cells. Purpose: You will get to see and identify the smallest unit of life! As well as learn about who discovered