Biology Exploring Life Chapter 1 Atom Molecule Macromolecule

Biology: Exploring Life Chapter 1

Atom Molecule Macromolecule Organelle Cell* Tissue Organ System Organisms Population Community Ecosystem Biosphere Hierarchy of Life

Cells are the structural and functional units of life Life emerges at the level of the cell Two main types of cells – Prokaryotic cells – – lack membrane bound organelles simple and small, range in size from 1 -10 µm – ex. bacteria – Eukaryotic cells – Have membrane bound organelles; – Can be a single cell, most are multicellular; 10 -100 µm – ex’s. plants, animals, fungi and protists

Prokaryotic cell DNA (no membrane around nucleus) Eukaryotic cell Membrane Nucleus = nuclear membrane around DNA) Organelles

True or False? 1. Life emerges at the level of the cell. 2. Prokaryotic cells are smaller and simpler than eukaryotic cells.

What is Life? ORDER ENERGY PROCESSING REGULATION GROWTH & DEVELOPMENT RESPONSE TO ENVIRONMENT REPRODUCTION EVOLUTIONARY ADAPTATION

Three Domains of Life

Domain Eukarya Includes Four Kingdoms: K. Protista K. Plantae K. Fungi K. Animalia

Living Organisms Interact with their Environments To be successful, an ecosystem must recycle chemicals necessary for life & move energy through the ecosystem Biotic and Abiotic components must interact to accomplish this

Living Organisms Interact with their Environments Biotic components Producers: Photosynthetic organisms that provide food for a typical ecosystem Abiotic components Chemicals & nutrients required for life Examples: Oxygen, Carbon dioxide, water, visible light, etc. Consumers: Eat plants (or eat animals that profit from/eat plants)

Sunlight Ecosystem Producers Cycling of chemical nutrients Heat Chemical energy Consumers Heat

The unity of life is Based on DNA and a common genetic code All cells have DNA is the chemical substance of genes A gene is a discrete unit of inheritance that transmits information from parents to offspring DNA is composed of two strands, coiled in a

Evolution Explains the Unity and Diversity of Life In 1859, Charles Darwin published On the Origin of Species by Means of Natural Selection Darwin emphasized two points: 1. descent with modification 2. natural selection is the mechanism of evolution

Darwin started with two observations 1. A population has Population 1 with varied inherited traits genetic variation 2. Overproduction of offspring Elimination of individuals with certain traits Reproduction of survivors

Evolution Explains the Unity and Diversity of Life Darwin inferred that unequal reproductive success would lead to the accumulation of favorable traits in a population Pangolin Killer whale

Evolution Explains the Unity and Diversity of Life

THE PROCESS OF SCIENCE

Scientists Use Two Main Approaches to Learn About Nature Two approaches are used to understand natural causes for natural phenomena – Discovery science which uses verifiable observations and measurements to describe science – Hypothesis-based science—uses the data from discovery science to explain science. – This requires proposing and testing of hypotheses

Hypotheses and Theories What is the difference between a theory and a hypothesis? – A hypothesis is a proposed explanation for a set of observations – The hypothesis must be testable and falsifiable – A theory is supported by a large and usually growing body of evidence

Observations Question

Observations Question Hypothesis 1: Dead batteries Hypothesis 2: Burned-out bulb

Observations Hypothesis 1: Dead batteries Question Hypothesis 2: Burned-out bulb Prediction 1: If the batteries are replaced Prediction 2: If the bulb is replaced then it will fix problem

Observations Question Hypothesis 1: Dead batteries Hypothesis 2: Burned-out bulb Prediction 1: If the batteries are replaced Prediction 2: If the bulb is replaced then it will fix problem Test predictions

Observations Question Hypothesis 1: Dead batteries Hypothesis 2: Burned-out bulb Prediction 1: If the batteries are replaced Prediction 2: If the bulb is replaced then it will fix problem Test predictions Test falsifies hypothesis Test does not falsify hypothesis