Biology and the Characteristics of Life

Aim: How do living things carry out metabolic activities? Do now: Answer the following question: How do you know if an organism is living? Vocabulary: life functions, homeostasis, develop, reproduction

What is Biology? the study of living things.

Living things are diverse. Largest animal is the blue whale. 33 yards in length (about 1/3 football field) weigh up to 130 metric tons (= 30 elephants)

Largest plant is the giant sequoia tree. Over 100 yards tall.

Smallest living things are bacteria. Size – meters 100 times smaller than a dot or period.

What makes a living thing “alive”? Characteristics of living things. All living things are made of cells. Unicellular = 1 celled (ex. Bacteria, yeast)

Multicelled = many cells (Frogs, mice, humans)

2) Living things maintain homeostasis. … a stable internal environment. EX: People sweat when they need to cool their bodies and shiver to warm them.

Living things reproduce and use DNA, the genetic material, to carry heritable information. 3) Reproduce

Asexual reproduction: only one organism, offspring are exactly like parent. (ex: Unicellular organisms divide by binary fission.) Two types of reproduction: asexual and sexual.

Sexual Reproduction: two organisms. Fertilization of egg cell by a sperm cell. Offspring will be a “mixture” of the parents.

4) Living things have organization subatomic particles --> atoms --> molecules --> organic molecules ---> cells --> tissues --> organs

5) Living things grow & develop Growth and development occur through cell division.

6) Living things obtain energy Organisms can obtain energy in 2 main ways: a) Autotrophs – make their own food (ex: plants & algae)

b) Heterotrophs – eat other organisms (ex: lions & tigers & bears)

7. Living things respond to stimuli They may move toward an external stimulus or away from it. Movement is part of the behavior of a living thing.

8. Living Things Evolve Groups Of Organisms (Not Individuals) change over time in order to survive within changing environments. Fossil records show changes in groups of organisms

QUIZ - Living things share 8 characteristics. Which two are missing from this list? Grow and develop Obtain energy Respond to stimuli Maintain homeostasis Reproduce Have organization