1. Biology & The Characteristics of Life

2. What is Biology?
Biology – the study of life
Bio- means life, and
-logy means the study of

3. Characteristics of Life

4. All living things share several unifying characteristics.

5. 1. Living things are based on a universal genetic code.
All living things store the complex information to live grow and reproduce in a molecule called DNA.

6. 2. Living things are made of cells
cells—the smallest working unit of living things

7. Unicellular and Multicellular organisms
Unicellular Organism- a single cell carries out all of life’s functions Ex> bacteria
Multicellular Organism- trillions of cells can be working together to carry out life functions, having specialized functions within the organism

9. 3. Living things grow & develop
organisms absorb raw materials and process them into new tissues and structures

10. Single celled organisms grow larger, while multicellular organisms grow by their cells dividing over and over.

11. 4. Living things obtain & use energy

12. Our ultimate energy source

13. Obtaining and using energy
For example, leaves obtain energy from the sun and gases from the air. These materials then take part in various chemical reactions within the leaves.
Animals ingest organisms like plants or other animals who have already consumed plants themselves.

14. Metabolism - A set of chemical reactions that occur in living organisms in order to maintain life.

15. 5. Living things respond to their environment
stimulus—anything detected in an organism’s environment that causes it to react
Ex. light, odor, sound, heat

16. Responses to stimuli
Some responses are behavioral, such as a rabbit running from a predator or a plant moving its leaves to face incoming sunlight. Other examples can include a plant producing a poisonous chemical to ward off insects from eating its leaves. Plants and animals can detect changes such as light, temperature, and even gravity.

18. Maintaining a balance
Organisms and their cells function best at certain temperatures, pH levels, solute concentrations, etc. They must maintain these levels from becoming too high or low.
Ex>Your body regulates the amount of glucose and water, as well as the temperature and pH level in your blood

19. Homeostasis The body’s ability to regulate its internal physiology to maintain stability in response to fluctuations in the outside environment

20. Homeostasis
Our bodies rely on a cycle of monitoring and responding to internal conditions called a negative feedback loop, similar to the way a thermostat operates in a home. It is called a negative feedback loop because any change to the system seen as a negative causes the system to return to its original state.

21. Homeostasis in your body
In low light environments, your pupils dilate and allow more light to pass into the eye. This is the body’s response to a stimulus, low light, to maintain constant light levels in the eye.

22. Thermoregulation – maintaining a stable body temperature.
The hypothalamus is part of the brain that regulates many of the body’s internal states, such as temperature. It senses temperature of blood passing through it and can cause:
Shivering and/or constriction of capillaries to conserve heat (warming)
Perspiration (sweat evaporating and carrying heat away from the body) and /or dilation of capillaries to release heat (cooling)

23. Thermoregulation
Warm blooded animals have a body temperature is independent of the external environment.
Other organisms, such as reptiles and amphibians, are cold blooded, meaning they rely on the environment to regulate their body temperature.

24. Warm vs. cold blooded

25. Warm blooded animals
-to generate heat, they convert food into energy; they have to eat a lot of food to maintain a constant temperature
-only a small amount of the food they eat is converted to body mass; it is used to fuel the constant body temperature.

26. Warm vs. cold blooded

27. Cold blooded animals
-are much more active in warm environments and are sluggish in cold environments because muscle activity depends on chemical reactions that are temperature dependent
-convert much more of their food into body mass compared with a warm- blooded animal

28. Osmoregulation – maintaining the balance of water and solutes (dissolved molecules and ions) in an organism.

29. 6. Living things have the ability to reproduce

31. Reproduction - Biological process by which new individual organisms are produced. A fundamental feature of all known life—each individual exists as a result of reproduction

32. Sexual Reproduction In sexual reproduction, offspring
are produced by the fusion of two sex
cells – one from each of two parents.
These fuse into a single cell before the offspring can grow.
The offspring produced inherit some genetic information from both parents.
Most animals and plants and many single-celled organisms reproduce sexually.

33. Asexual Reproduction
Asexual reproduction - reproduction that involves a single parent producing an offspring. The offspring produced are, in most cases, identical to the single cell that produced them.
Asexual reproduction is a simple, efficient, and effective way for an organism to produce a large number of offspring.
Many simple cells, such as a blood cell, single-celled organisms, such as a bacteria, and many multicellular organisms can reproduce asexually.

34. Asexual Reproduction
In multicellular organisms, cell division is an example of asexual reproduction that leads to growth and also enables repair and maintaining of its body.

35. Examples of Asexual Reproduction
Bacteria reproduce by binary fission
Kalanchoe plants form plantlets.
Hydras reproduce by budding.

36. Asexual reproduction

37. Comparing Sexual and Asexual Reproduction

38. An individual living thing Ex. tree, frog, human
Organism
An individual living thing Ex. tree, frog, human

39. 7. Living things evolve

40. Evolution
Over generations, groups of organisms evolve, or change over time.
Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago.

41. Evolution
Evidence of this shared history is found in all aspects of living and fossil organisms, from physical features to structures of proteins to sequences of information in DNA.
For example, signs of one of the first land plants, Cooksonia, are preserved in rock over 400 million years old.