#1: Organismal Biology and Evolution

Organismal Biology

• Biology: the scientific study of life

• Terms originated from greek (bio)/(logy)

• Survey of the diversity of life on earth

• Analysis of different forms of life

• There’s unifying characteristics 

• Characteristics of all biological living organisms (not all of the 7 all together)

1. Made of a cell: basic unit of life

• Cell theory: Every living organism is made of one or more cells
• unicellular or multicellular: group of cells specialized for certain function
• All cells are enclosed with a membrane and regulates passage of materials

1. Organized structure 

• Example: bicycle has all of components, but must be organized in a particular way

1. Energy usage

• Plants uses photosynthesis for glucose 
• Animals use cellular respiration 

1. Growth and Development: inherited information from genes controls the patterns

• Growth: in dimension
• Development: change of form 

1. Reproduction
2. Respond to Stimuli

• Comes from the environment

• Feedback regulation: the output or product of a process regulates that very process

• Negative: in a loop which response reduces initial stimulus, insulin

• Positive: end products speeds up its own production, blood clots

• Examples: getting overheated

1. Ability to evolve

• Reproductions over time come with changes to adjust to the changing environment

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New properties emerge at the successive levels of biological organization

• Life can be studied at different levels from molecules to the entire living planet

• Enormous range can be divided into different levels of biological organization

• Emergent properties: arrangement and interactions of parts as complexity increases

• Systems biology:  the exploration of biological system by analyzing interactions among its parts

• Reductionism: complex systems to simplers ones

• Smallest to Largest: Molecules → Organelles → Cells → Tissues →Organs/Organs Systems →Organism →Populations → Communities → Ecosystems → Biosphere

Definitions 

• Molecules: chemical structure consisting of two or more units called atoms

• Organelle: various functional components present in cells

• Cell: life’s fundamental unit and structure

• Eukaryotic: membrane-enclosed organelles

• Prokaryotic: lack a nucleus or other membrane enclosed organelles + smaller

• Tissue: group of cells that work together performing a specific function

• Organ: a body part that is made up of different tissues and has specific functions in the body.

• Each tissue has distinct arrangement and contributes particulars properties

• Organisms: individual living things

• Populations: individuals of the same species to be in a particular area and make and reproduce

• Communities: all the living organisms and species that inhabit a certain area (all living, not one group)

• Ecosystem: interactions between living and non-living organisms

• Non-living example: water, soil, sunlight

• Biosphere: our entire planet and the biodiversity of the ecosystems 

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Life’s Processes Involved Expression/ Transmission of Genetic Information

• DNA contains thousands of genes and encode information to build molecules to establish cell identity

• Double helix 

• A,T, C and G sequences to analog

• A-T = 2 hydrogen bonds 

• C-G = 3 hydrogen bonds

• Genetic information encoded DNA for development

• Stores information

• RNA: protein encoding genes controlling protein production and a gene is transcribed for functional processes– the gene expression is through information

• Genome:  genetic instructions, the entire collection of the genes

• Genes: chromosomes of DNA that encode for particular function

• Transcription to Translation to Protein Folding

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Life Requires Transfer and Transformation of Energy and Matter

• Consumers: feeds on other organisms

• Producers: chemical energy

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Classifying the Diversity of LIfe

• 1.8 million species have been identified and named to date and thousands more are identified each year

• Estimates of the total number of species that actually exist range from 10 million to over 100 million

• Taxonomy: branch of biology that names and classifies species into groups of increasing breadth according to their characteristics 

• Domains → Kingdoms → Phylum → Class → Order → Family → Genus → Species 

• Eukarya (all of the eukaryotic cells) → Animalia → Chordata → Mammalia → Carnivora → Ursidae → Ursus 

• The characteristics become more inclusive as you move down the pyramid 

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• Three Domains of Life

1. Bacteria: prokaryotes 

• Unicellular
• Have a cell wall that has lipids and esther-liked 
• Lacks a nucleus
• Single cells growing in colonies
• Common ancestor

1. Archaea: prokaryotes

• Unicellular

• Lacks a nucleus

• Metabolic activities and functions

• Extremophile

• Able to obtain energy 

1. Eukarya: all living things made eukaryotic

• Divided into Kingdoms

• Examples: Plantae, Fungi, Protists and Animalia

• Protists:

• AREN’T a kingdom, 

• all of the other organisms, heterogenous group

• Multicellular

• Plants: photosynthetic, makes the energy through the use of sunlight (H2O +CO 2)

• Animalia: cellular respiration: breaks down the sugar through ingestion

• Fungi: absorbs nutrients through photosynthesis

Ecology: 

• Exploration of the ecological relationships

• Ecology: the study of how organisms interact with each other and their environment 

• Changes of the environments changes their ability to survive

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Evolution: underlying process that accounts for the diversity of life on earth

• Can’t always be adaptable and or change

• Aren’t identical or individual

• Processes of the change that has transformed life on earth from its earliest beginnings to the diversity of organisms living today

• Explains the unity and diversity: how one can be generated by billions of years

• Having the similar components of the characteristics of living organisms

• Adaptation: inherited characteristic of an organism that enhances its survival and reproduction in a specific environment 

• Enables us to understand how organisms vary with their environment 

• Variation within a species

• Can increase survival and rate of reproduction through genetic mutations

• Same species can have variation

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Natural Selection

1. Species adapt to different environments over time and accumulate differences from ancestors – descent with modification
2. “Natural selection” caused the differences 

• They varied in traits that were heritable

• Produced more offspring for survival

• Generally were suited in their environments (adapted)

• Natural environment “selected” propagation of certain traits

• Organisms vary– some of this variation is heritable 

• Genetic material, sexual production (gametes) which will influence evolution