Summer work Chapters 1, 6 and 25

History of Life on Earth

Fig 25-UN8 Millions of years ago (mya) 1.2 bya: First multicellular eukaryotes 2.1 bya: First eukaryotes (single-celled) 3.5 billion years ago (bya): First prokaryotes (single-celled) 535–525 mya: Cambrian explosion (great increase in diversity of animal forms) 500 mya: Colonization of land by fungi, plants and animals Present 500 2,000 1,500 1,000 3,000 2,500 3,500 4,000

Early Earth  Miller/Urey experiment:  Created early earth atmosphere  Produced aa

Early Earth  Protobionts:  Collections abiotic materials  Membrane-like structures  Ribozymes:  RNA catalysts

Fig Ancestral photosynthetic eukaryote Photosynthetic prokaryote Mitochondrion Plastid Nucleus Cytoplasm DNA Plasma membrane Endoplasmic reticulum Nuclear envelope Ancestral prokaryote Aerobic heterotrophic prokaryote Mitochondrion Ancestral heterotrophic eukaryote

Prokaryotes  Stromatolites:  Layers of rock  Prokaryotes  3.5 billion years ago

Oxygen  Photosynthetic bacteria  Cynobacteria  2.7 billion years ago

Macroevolution  Evolutionary change above a species  Evolution over a large time

Change in dominant groups  1. land movement  2. mass extinctions  3. adaptive radiation

Fig South America Pangaea Millions of years ago Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present

Mass extinctions  5 over past 500 mya  Permian (251 mya)  Eliminated 75% marine life  Massive volcano eruptions  Cretaceous (65.5 mya)  Dinosaurs  ?? asteroid

Mass extinction  Decrease diversity  Change ecological communities  Allows some species to thrive  Humans evolved

Adaptive radiation  Organisms form new species  Evolve to fill new communities  Occurred after extinctions  Now vacant niches  Mammals  Hawaii

Biology: science of life

Properties of living things  Order  Sensitivity  Regulation  Growth, development,and reproduction  Energy utilization  Evolutionary adaptation

Themes Unite Biology  The cell theory  Continuity of Life  Diversity of Life  Unity of Life

Cell theory  All living things consist of cells  All cells come from cells  Prokaryotic  Eukaryotic

Continuity of life  Inheritance of information  DNA

Evolution  Big Idea #1  Organisms have changed over time  Diversity of new forms  Natural selection

Diversity of Life  Domains Bacteria Archaea Eukarya  Kingdom Protista  Kingdom Plantae  Kingdom Fungi  Kingdom Animalia

Unity of Life  Unifying themes among all living things  DNA  Flagella

The cell

Membrane  Separates living cell from its surroundings  Two layers  Phospholipids & proteins

Nucleus  DNA, chromosomes  Nucleolus: synthesis of rRNA  Nuclear envelope: double membrane  Nuclear pores: surface of the nucleus function like channels.

Endoplasmic Reticulum  Endomembrane system  Protein & lipid synthesis  Rough ER Ribosomes: site of protein synthesis  Smooth ER Synthesis of carbohydrates and lipids

Golgi bodies  Flattened stack of membranes  Collection, packaging & distribution of molecules  Proteins & lipids enter the apparatus  Modified  Distributed to new location

Lysosomes  Digestive vesicles  Breakdown proteins, carbohydrates, nucleic acids and lipids  Break down old organelles Ex: mitochondria are replaced in some tissues every 10 days

Mitochondria  Tubular or sausage shaped organelles  Power house of the cell  DNA to make proteins needed for metabolism

Chloroplasts  Light energy to manufacture organic molecules  Chlorophyll give plants green color  Contain DNA

Centrioles  Barrel shaped organelles  Right angles near the nucleus  Help assemble the cells microtubules

Cytoskeleton  Supports the shape of the cell  Contain 3 types of fibers Microfilaments (actin fibers) Microtubules Intermediate filaments