Honors Biology

1. Characteristics of living things1. Composed of cells2. obtain and use food for energy3. reproduce4. respond to stimuli5. adapt to the environment6. require water to survive7. maintain homeostasis8. have a metabolism9. produce waste Honors Biology

2. Living things Obtain and Use Food for Energy

3. Living Things are based on a Universal Genetic Code • There is a specific molecule used within the cells of ALL living things to store the complex information they need to • Live • Grow • Reproduce • What is this molecule called?? • DNA (Deoxyribonucleic Acid) • DNA is the genetic material of the cell which contains codes for the building of proteins.

4. Living Things are taken as a group, living things Evolve • Pass on traits (characteristics) from one generation to the next by their DNA • Cannot generally choose or change their characteristics • An organisms traits are largely predetermined by their DNA • Though it may be influenced by their environment

5. Living Things are taken as a group, living things Evolve • Examples of Types of Traits: • Physical • Physiological • Behavioral

6. Living Things are taken as a group, living things Evolve

7. What kind of traits are shown? Physical Physiological

8. How do these new traits arise?? • How are traits controlled ?? • Individual’s genes • In sexually reproducing species, variations arise from unique combinations of the mother and father’s genetic material • Variations are differences in organisms • In sexually and asexually reproducing species, variations can also arise from random/chance mutations • Change the genetic material of a cell • Mutations can be helpful, harmful, or have no impact!

9. What’s a Mutation anyway?? • Mutation • Change in the genetic material of a cell

10. As a group, living things adapt to their environment over time • Variations may enhance an organism’s ability to survive & reproduce • These traits are referred to as adaptations • What’s an adaptation? • Heritable characteristic that increases an organism’s ability to survive and reproduce in an environment

11. As a group, living things adapt to their environment over time • Environment largely dictates what is an adaptation and what is not. • A trait may benefit survival in one environment and hinder survival in another • Ex – think of a snowshoe hare trying to hide in a NJ Forest!

12. As a group, living things adapt to their environment over time • How do populations change/evolve over time??? • Natural Selection • The process by which organisms that are best suited to their environment survive and reproduce most successfully (=survival of the fittest) • Individuals are selected, a species adapts and evolves

13. Example of evolution • Two shades of peppered moths (light/dark) lived simultaneously in England before the industrial age.

14. The trees were light at the time since they were covered in “lichens” (a fungus/algae) • Which moths were harder to spot “before” the Industrial revolution???

15. Birds spotted the darker moths and the population of darker moths decreased • In other words, the “lighter” ones were “selected for” • During the IR, there was so much pollution that the darker lighter colored lichen on the trees were killed, thus making the trees appear darker… • Which moths were harder to spot “after” the IR?

16. Birds spotted the lighter moths now and the population of lighter moths decreased. • In other words, the “darker” ones were “selected for” • This shows how the environment drives natural selection (influences the selection of traits)

17. Each time an organism reproduces, there is a chance that the DNA of the offspring will lead to new and different traits which may enhance their survival. • If the trait benefits the organism, the organism is more ‘fit’ for survival and reproduction of another generation of offspring (their genes are getting passed on)

18. The new trait may be passed on to the next generation of offspring • Eventually, if successful then this trait will be present in a greater % of the population • The group of organisms can be said to have adapted to their environment

19. As one adaptation follows another, eventually the species may undergo subtle or even drastic changes. Over time groups of organisms can become different enough from one another that they are considered a new species.

20. Evolution • Change over time • The process by which modern organisms have descended from ancient organisms • Evidence points to a common ancestor of all life forms which dates back over 3.5 billion years.

21. We can’t live forever! • Over time there is damage to DNA and cells • Wear out, despite constant maintenance and repair throughout the organism’s life time • Cannot always maintain homeostasis in all environmental conditions • Cannot continue its metabolism and maintain homeostasis, its life will cease. • Earth has a limited supply of resources • Death – materials in cells are recycled back into the environment for use by new generations of living things

23. Decomposers are essential to the recycling of materials between the living and non-living portions of every ecosystem • All this dead ‘stuff’ has run out of energy. It can’t grow any more. • But it is still vital to life, because it contains atoms that are the basic building blocks of all living things. • These atoms get recycled into the food web with the help of organisms called decomposers. 

24. Viruses • There is some debate over whether viruses are living or nonliving. Most agree that they are nonliving. Why? • They are unable to INDEPENDENTLY carry out all life processes. They are known as “obligate intracellular parasites”. • They are particles made of nucleic acid and protein that can replicate only by infecting living cells. • Do not belong to any kingdom and don't contain any cells. Therefore, they are considered nonliving.