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1.2 Unifying Themes of Biology Bell ringer: • 1- How does biodiversity depend on a species ability to reproduce???? • 2- You respond automatically to many different stimuli, such as loud noises. Why might a quick response to a sound be important?? 1.2 Unifying Themes of Biology www.classzone.com -vocab flash cards 1.2 Unifying Themes of Biology KEY CONCEPT Unifying themes connect concepts from many fields of biology. 1.2 Unifying Themes of Biology All levels of life have systems of related parts. • A system is an organized group of interacting parts. – A cell is a system of chemicals and processes. – A body system includes organs that interact. – An ecosystem includes living and nonliving things that interact. 1.2 Unifying Themes of Biology • Biologists study many different systems. – Ex. Geneticist versus ornithologist 1.2 Unifying Themes of Biology “How can this biology class be considered a system?” 1.2 Unifying Themes of Biology Structure and function are related in biology. • Structure determines function. – Ex. Eating: bite with front & chew with molars. – Proteins with different structures perform different functions. – Heart muscle cells have a different structure and function than stomach muscle cells. – Different species have different anatomical structures with different functions. 1.2 Unifying Themes of Biology “Do you think heart muscle has the same structure as arm muscle? Why?” 1.2 Unifying Themes of Biology Why do you shiver when cold? Sweat when hot? Feel thirsty when you need water? 1.2 Unifying Themes of Biology Organisms must maintain homeostasis to survive in diverse environments. 1.2 Unifying Themes of Biology • Homeostasis is the maintenance of constant internal conditions. • Its important because cells function best within a limited range of conditions. 1.2 Unifying Themes of Biology • Homeostasis is the maintenance of constant internal conditions. – Homeostasis is usually maintained through negative feedback. – Negative feedback systems return a condition to its normal (set) point. 1.2 Unifying Themes of Biology • Behaviors and adaptations can help maintain homeostasis. – Ex. Basking reptiles 1.2 Unifying Themes of Biology BELL RINGER • So far we have discussed 3 Unifying Themes in Biology. What are they?................... • When you are finished look over your terms! 1.2 Unifying Themes of Biology “Why is homeostasis important?” 1.2 Unifying Themes of Biology Evolution explains the unity and diversity of life. • Evolution is the change in living things over time. – The genetic makeup of a population of a species changes. - Supported by fossil record & genetic comparisons 1.2 Unifying Themes of Biology – Evolution can occur through natural selection of adaptations. – Adaptations are beneficial inherited traits that are passed to future generations. – Populations can also change due to different environments. 1.2 Unifying Themes of Biology –Ex. Finches 1.2 Unifying Themes of Biology • Evolution accounts for both the diversity and the unity of life. • Shared characteristics result from common evolutionary descent. – Ex. Humans versus bacteria 1.2 Unifying Themes of Biology “How does evolution lead to both diversity & similarities of life?”