Exploring Life copyright cmassengale 1 Themes Help to

Exploring Life copyright cmassengale 1

Themes Help to Organize Biological information copyright cmassengale 2

Unifying Themes in Biology z Evolution~ biology’s core theme; differential reproductive success z Emergent Properties~ hierarchy of life (new properties at each level) z The Cell~ all organism’s basic structure z Heritable Information~ DNA z Structure & Function~ form and function (Form determines function) z Environmental Interaction~ organisms are open systems z Regulation~ feedback mechanisms z Unity & Diversity~ universal genetic code z Scientific Inquiry~ observation; testing; repeatability copyright cmassengale 3

Prokaryotic cell Eukaryotic cell Membrane DNA (no nucleus) Membrane Cytoplasm Organelles Nucleus (contains DNA) copyright cmassengale 1 µm 4

Life can be divided into different levels of biological organization copyright cmassengale 5

The biosphere Organs and organ systems Cells 10 µm Cell Ecosystems Organelles Communities 1 µm Tissues Populations Atoms 50 µm Molecules Organisms copyright cmassengale 6

The biosphere Ecosystems Communities Populations copyright cmassengale Organisms 7

Organs and organ systems 10 µm Cells Cell Organelles 1 µm Tissues Atoms 50 µm Molecules copyright cmassengale 8

Hierarchy of Organization z Molecule z Organelle z Cells z Tissues z Organ z Systems z Organism copyright cmassengale 9

Macromolecules z. Carbohydrates (CHO) - energy z. Lipids (CHO) – long term energy z. Proteins (CHON) – building & work z. Nucleic acids (CHONP) – genetic information copyright cmassengale 10

Feedback Regulation: Negative z Accumulation of an end product of a process slows that process z Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway copyright cmassengale 11

Feedback Regulation: Positive z. An end product speeds up its production z. Example: blood clotting in response to injury copyright cmassengale 12

The Process of Science z. Scientific Method z. Deductive reasoning z“If…. then” Logic z. Hypothesis (testable) z. Theory (widely tested & accepted) z. Law (proven) copyright cmassengale 13

Properties of Living Things Which is considered living? Why? Paramecium copyright cmassengale Bacteriophage 14

Early Views of Life z. Vitalism: The insistence that there is some big, mysterious extra ingredient in all living things z Led to idea of spontaneous generation (life can come from nonliving material) y. Flies came from dead animals y. Mice came from Hay copyright cmassengale 15

The Redi Experiment z. Idea was challenged by scientist Francesco Redi in 1698. z. Designed an experiment where 3 jars contained meat. copyright cmassengale 16

Setup 1 z. One Jar contained meat and had an open top which would allow the passage of flies. y(maggots would appear on the meat) copyright cmassengale 17

Setup 2 z. The second jar was covered with an airtight lid not allowing the passage of flies. y(no maggots would appear on the meat) copyright cmassengale 18

Setup 3 z. The third was covered by a screen allowing passage of eggs, but not flies. y(few maggots would appear on meat) copyright cmassengale 19

Conclusion z. Since third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots. (Deductive Reasoning) y. Led to theory of Biogenesis x. All life comes from preexisting life copyright cmassengale 20

Life is Recognized by What Living Things Do copyright cmassengale 21

Order Response to the environment Evolutionary adaptation Regulation Energy processing copyright cmassengale Reproduction Growth and development 22

PROPERTIES of LIFE z. Be made of Cells. z. The Cell is the basic unit of life y. Is self contained and possesses a barrier (membrane) which separates itself from the environment. z. Two types of organisms. y. Unicellular - One celled organism (Uni=1) y. Multicellular - Many cells (Multi=”many”) copyright cmassengale 23

Cells z. The cell is the lowest level of organization that can perform all activities required for life z. All cells: y. Are enclosed by a membrane y. Use DNA as their genetic information z. The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms copyright cmassengale 24

PROPERTIES of LIFE z Living Things must Reproduce. z Must be able to create more of it’s own kind z Two types of reproduction: y. Sexual - Two parent organisms combine genetic material to produce the offspring. y. Asexual - When a single organism can divide or “bud” to create it’s offspring without another of it’s species. copyright cmassengale 25

PROPERTIES of LIFE z. Living things ALL Have DNA. z. Universal Genetic Code z. Instructions for making all the bodies proteins z. Located in the nucleus (eukaryotes) or nucleiod region (prokaryotes) copyright cmassengale 26

DNA z. Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid) z. DNA is the substance of genes z. Genes are the units of inheritance that transmit information from parents to offspring copyright cmassengale 27

z. Each chromosome has one long DNA molecule with hundreds or thousands of genes z. DNA is inherited by offspring from their parents z. DNA controls the development and maintenance of organisms copyright cmassengale 28

Sperm cell Nuclei containing DNA Egg cell Fertilized egg Embryo’s cells with DNA from copies of inherited DNA both parents Offspring with traits inherited from both parents copyright cmassengale 29

z. Each DNA molecule is made up of two long chains arranged in a double helix z. Each link of a chain is one of four kinds of chemical building blocks called nucleotides (A, T, C, G) copyright cmassengale 30

Nucleus DNA Nucleotide Cell (a) DNA double helix (b) Single strand of DNA copyright cmassengale 31

z. Genes control protein production indirectly z. DNA is transcribed into RNA then translated into a protein z. An organism’s genome is its entire set of genetic instructions copyright cmassengale 32

PROPERTIES of LIFE z Living things must Grow & Develop. z Growth refers to two processes. y. Increase in the number of cells. y. Increase in the size of cells. z Development refers to changes in the organism which occur through it’s lifespan. y. Includes cell differentiation. y. Includes organ development y. Includes aging & death. copyright cmassengale 33

PROPERTIES of LIFE z Living things obtain & use energy. z Energy is used by all living things for growth, development & reproduction. y. Life processes which result in “building” the organism ia known as Anabolism. (endergonic-store energy) y. Life process where energy is extracted by “breaking-down” substances is called Catabolism. (exergonic-release energy) z ATP – cellular energy copyright cmassengale 34

PROPERTIES of LIFE z Living things must Respond (or react) to their environment in some way. z Something which causes an organism to react is known as a Stimulus (stimuli). z The ability of an organism to react is called Irritability. z Most responses are geared for maintaining Homeostasis. y. Homeostasis is a process where an organism maintains a stable internal environment so life can continue. y. Some examples include temperature, p. H, and water content of the cell. copyright cmassengale 35

Organisms Interact with Their Environments z Every organism interacts with its environment, including nonliving factors and other organisms z Both organisms and their environments are affected by the interactions between them y. For example, a tree takes up water and minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil copyright cmassengale 36

Ecosystem Dynamics z. The dynamics of an ecosystem include two major processes: y. Cycling of nutrients, in which materials acquired by plants eventually return to the soil (Carbon, Phosphorus, Water, Nitrogen) y. The flow of energy from sunlight to producers to consumers copyright cmassengale 37

Sunlight Ecosystem Cycling of chemical nutrients Producers (plants and other photosynthetic organisms) Heat Chemical energy Consumers (such as animals) Heat copyright cmassengale 38

Evolution unifies biology at different scales of size throughout the history of life on Earth copyright cmassengale 39

Diversity of Life z. Approximately 1. 8 million species have been identified and named to date, and thousands more are identified each year z. Estimates of the total number of species that actually exist range from 10 million to over 100 million copyright cmassengale 40

Grouping Species z. Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth z. Domains, followed by kingdoms, are the broadest units of classification copyright cmassengale 41

Species Genus Family Order Class Phylum Kingdom Domain Ursus americanus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Animalia Eukarya copyright cmassengale 42

The Three Domains of Life z. The three-domain system is currently used, and replaces the old five-kingdom system z. Domain Bacteria and domain Archaea comprise the prokaryotes z. Domain Eukarya includes all eukaryotic organisms copyright cmassengale 43

(a) DOMAIN BACTERIA (b) DOMAIN ARCHAEA (c) DOMAIN EUKARYA Protists Kingdom Plantae Kingdom Fungi copyright cmassengale Kingdom Animalia 44

DOMAIN BACTERIA copyright cmassengale 45

DOMAIN ARCHAEA copyright cmassengale 46

Eukarya z. The domain Eukarya includes four kingdoms: y. Protista (unicellular) y. Fungi (mostly multicellular) y. Plantae (multicellular) y. Animalia (multicellular) copyright cmassengale 47

Protists Kingdom Plantae Kingdom Fungi (c) DOMAIN EUKARYA Kingdom Animalia copyright cmassengale 48

Protists copyright cmassengale 49

Kingdom Fungi copyright cmassengale 50

Kingdom Plantae copyright cmassengale 51

Kingdom Animalia copyright cmassengale 52

Fossils and other evidence document the evolution of life on Earth over billions of years copyright cmassengale 53

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Natural Selection z Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 z Darwin made two main points: y. Species showed evidence of “descent with modification” from common ancestors y. Natural selection is the mechanism behind “descent with modification” z Darwin’s theory explained the duality of unity and diversity copyright cmassengale 55

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Descent with Modifications copyright cmassengale 57

z. Darwin observed that: y. Individuals in a population have traits that vary y. Many of these traits are heritable (passed from parents to offspring) y. More offspring are produced than survive y. Competition is inevitable y. Species generally suit their environment copyright cmassengale 58

z. Darwin inferred that: y. Individuals that are best suited to their environment are more likely to survive and reproduce y. Over time, more individuals in a population will have the advantageous traits z. In other words, the natural environment “selects” for beneficial traits copyright cmassengale 59

1 Population with varied inherited traits. 2 Elimination of individuals with certain traits. 3 Reproduction of survivors. copyright cmassengale 4 Increasing frequency of traits that enhance survival and reproductive success. 60

z. Natural selection is often evident in adaptations of organisms to their way of life and environment z. Bat wings are an example of adaptation copyright cmassengale 61

The Tree of Life z“Unity in diversity” arises from “descent with modification” y. For example, the forelimb of the bat, human, horse and the whale flipper all share a common skeletal architecture z. Fossils provide additional evidence of anatomical unity from descent with modification copyright cmassengale 62

z. Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species y. For example, the finch species of the Galápagos Islands z. Evolutionary relationships are often illustrated with tree-like diagrams that show ancestors and their descendents copyright cmassengale 63

Gray warbler finch Certhidea fusca Bud-eater Seed-eater Insect-eaters Warbler finches COMMON ANCESTOR Green warbler finch Certhidea olivacea Sharp-beaked ground finch Geospiza difficilis Vegetarian finch Platyspiza crassirostris Mangrove finch Cactospiza heliobates Insect-eaters Tree finches Woodpecker finch Cactospiza pallida Medium tree finch Camarhynchus pauper Large tree finch Camarhynchus psittacula Cactus-flower -eaters Seed-eaters Ground finches copyright cmassengale Small tree finch Camarhynchus parvulus Large cactus ground finch Geospiza conirostris Cactus ground finch Geospiza scandens Small ground finch Geospiza fuliginosa Medium ground finch Geospiza fortis Large ground finch Geospiza magnirostris 64

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