Introduction to Human Biology Biological Properties of Humans Scientific Process

Biological Inquiry  Bio = of living things  What Are the Characteristics of Humans as Living Organisms?  How Do Biologists Study Living Things?

Characteristics of Living Things Propose as many differences as you can between a living organism and a non-living thing. fungal mycelia on a corn tortillaGloeocapsa medicinal leech Giardia meerkats cotton

Characteristics of Humans as Living Organisms Humans are highly organizedHumans are highly organized –Composed of many cells = multicellular –cells  tissues  organs  organ systems Organic molecules = carbon-containing building blocks of life Organic molecules = carbon-containing building blocks of life

Organizational Hierarchy of the Human Body Organ System Central Nervous System Organ Brain Tissue Nerve Cell Neuron Smallest Unit of Life

Human Cells are Highly Organized Organelle: region of cell with specialized function

Characteristics of Humans As Living Organisms Human beings acquire and use materials and energyHuman beings acquire and use materials and energy Energy = ability to do work Energy = ability to do work Metabolism = sum of chemical reactions in an organism Metabolism = sum of chemical reactions in an organism

Characteristics of Humans As Living Organisms Human beings reproduce, grow and developHuman beings reproduce, grow and develop Growth = increase in size Development = change in characteristics

Characteristics of Humans As Living Organisms Human beings use DNA reproduce themselves.Human beings use DNA reproduce themselves. The molecule of heredity = The molecule of heredity = DNA = deoxyribonucleic acid DNA = deoxyribonucleic acid

Sub-Cellular Organizational Hierarchy of Life with Examples sub-atomic particles atom molecule protons, neutrons, electrons nitrogen nucleotide gene chromosome genome organellenucleusmacromoleculeDNAcellneuron

A nucleotide molecule contains a phosphate group, sugar and base.

Nucleotides are linked together to form chains.

DNA contains two nucleotide chains wound together in a helical shape.

Each human chromosome is a single, long DNA molecule compacted by proteins.

A gene is a sequence of nucleotides that provides instructions for producing a protein. 6 30,000

Characteristics of Humans As Living Organisms Living things maintain homeostasis = state of internal constancy

Characteristics of Humans As Living Organisms Human beings respond to stimuli from their environmentHuman beings respond to stimuli from their environment

Characteristics of Humans as Living Organisms Human beings adapt and evolveHuman beings adapt and evolve Evolution = change in characteristics over time Adaptation = characteristic that promotes survival and reproduction Evolution = change in characteristics over time Adaptation = characteristic that promotes survival and reproduction

How Do We Categorize Living Things? Three DomainsThree Domains –Eukarya –Archaea –Bacteria Domain Eukarya Domains Archaea and Bacteria prokaryotic eukaryotic Eukaryotes have a membrane-bound nucleus and extensive internal membranes Prokaryotes have no membrane-bound nucleus and few internal membranes

How Do We Categorize Living Things? Eukarya has four kingdomsEukarya has four kingdoms –Protista: mostly single celled –Fungi: multicellular, digest nutrients outside the body –Plantae: multicellular, photosynthetic –Animalia: multicellular, internal digestion Domain Eukarya Kingdom Animalia Kingdom Plantae Kingdom Fungi Kingdom Protista

Increasing Levels of Organizational Hierarchy organ system organism population Members of the same species in the same area community Interacting populations in the same area ecosystem Community + Non-living factors Biosphere All ecosystems on earth: zones of air, land and water that support life

Characteristics of Humans As Living Organisms Human beings are members of the biosphereHuman beings are members of the biosphere

Characteristics of Humans as Living Organisms Human Beings 1.are highly organized with levels from cells  tissues  organs  organ systems 2. acquire and use materials and energy. 3. maintain homeostasis. 4. respond to stimuli from their environment. 5. reproduce, grow and develop. 6. adapt and evolve. 7. are members of the biosphere.

Unique Characteristic of Humans Human beings have a cultural heritageHuman beings have a cultural heritage

How Do Biologists Study Living Things? Observation New observations are made, and previous data are studied. Hypothesis Input from various sources is used to formulate a testable statement. Experiment The hypothesis is tested by experiment or further observations. Conclusion The results are analyzed, and the hypothesis is supported or rejected. Scientific Theory Many experiments and observations support a Theory. Principle A theory supported by evidence over a long period of time, Scientific Method

How Do Biologists Study Living Things? Scientific Method Hypothesis Conclusion Observations Experiment/ Observations Specific nutrients in almonds can reduce LDL cholesterol in people with high blood lipid levels. People who eat almonds as snacks have improved blood lipid profiles.

How Do Biologists Study Living Things? Experimental Design Subjects divided intoSubjects divided into –Experimental (Test) Group –Control Group: treated like test group except for a difference in one variable being tested Avoiding Bias in Human StudiesAvoiding Bias in Human Studies –Blind Study: subject does not know if they are assigned to test or control group –Double-blind Study: neither subject nor investigator know who is assigned to test and control groups

How Do Biologists Study Living Things? Scientific Method Hypothesis Conclusion Observations Experiment/ Observations Specific nutrients in almonds can reduce LDL cholesterol in people with high blood lipid levels. People who eat almonds as snacks have improved blood lipid profiles. Subjects used three equal calorie supplements in separate one month periods: Muffins (low saturated fat) Half Almonds + Half Muffins Almonds

Experimental Results  Do the results show that almonds change the LDL cholesterol levels in these subjects?  What characteristics of almonds would account for the difference from the control supplement?

How Do Biologists Study Living Things? Scientific Method Hypothesis Conclusion Observations Experiment/ Observations Specific nutrients in almonds can reduce LDL cholesterol in people with high blood lipid levels. People who eat almonds as snacks have improved blood lipid profiles. Subjects used three equal calorie supplements in separate one month periods: Muffins (low saturated fat) Half Almonds + Half Muffins Almonds Monounsaturated fats (and possibly protein and fiber) of almonds caused a decrease in LDL cholesterol.