BIO 101 Chapter 1

Introduction: Themes in the Study of Life

Evolution

• is the process of change that has transformed life on Earth

• it is the history of life on earth

Biology

• the scientific study of life

what are some questions biologists ask

• how a single cell develops into an organism

• how the human mind works

• how living things interact in communities

what are some properties of life

• order

• evolutionary adaptation

• response to the environment

• reproduction

• growth and development

• energy processing

• regulation

organims living on earth are ______ of common ancestors

modified descendents

these are the levels of biological organization, describe each component

• the smallest component is the atom, they stick to other atoms which make molecules

• molecules —>organelles

• organelles —> cells

• a collection of cells make up tissues

• the leaf represents an organ on a tree

• the tree represents the organism

• organisms fit together to form a population

• a population consists of all the members of the same species in the same space

• the community is made up of members of different species in the same space

• all plants, animals, and nonliving features are a part of the ecosystem which comes together to form the biosphere

emergent properties

• it is a result from the arrangement and interaction of parts within a system

  • ex. (nonbiological) a functioning bicycle emerges only when all of the necessary parts connect in the correct way

reductionism

• understanding biological systems by breaking them down into their simpler components

• by examing the individual parts we can gain insight into how the whole system functions

  • ex. studying a single gene to understand its role in a larger biological process

• an understanding of biology balances reductionism with the study of emergent properties

  • ex. new understanding comes from studying the interaction of DNA with other molecules

systems biology

• focuses on understanding complex biological systems as integrated wholes rather than just their parts

• aims to study interaction and relationships between different biological components (genes, proteins, cells, tissues) and how they lead to the function and behavior of the entire system

organisms interact with their _____, exchanging matter and energy

environment

the dynamics of an ecosystem include what two major processes

• cycling of nutrients, in which materials acquired by plants eventually return to the soil

• the flow of energy from sunlight to producers to consumers

why is the energy coming from sunlight not a cycle

becuase none of that heat or light is getting put back into the sun

work requires a source of ____

energy

what forms can energy be stored in

• light

• chemical

• kinetic

• thermal

energy flows though an ecosystem, usually entering as ____ and exiting as ___

light, heat

describe the relationship between structure and function

• they are closley related,

• everything in biology has a certain structure because of its function

  • ex. a leaf is thin and flat (structure) which maximizes the ability to capture light by chloroplasts (function)

  • ex. flowers are bright and colorful (structure) so it can attract pollinators and reproduce (function)

the ___ is the lowest leve of organization that can perform all activites required for life

cell

all cells are:

• enclosed by a membrane

• use DNA as their genetic information

what is the basis of all reproduction, growth, and repair of multicelular organisms

the ability of cells to divide

describe a eukaryotic cell

• plant, animal, fungi, protus

• has a membrane around the outside and a series of membrane enclosed organelles on the inside

• contain nucleus (DNA is present here)

• bigger than prokaryotic cell

describe a prokarytoic cell

• bacteria and archae

• does not contain membrane-enclosed organelles

• has no nucleus

• smaller than eukaryotic cells

• DNA is present

the continuity of life is based on heritable information in the form of ___

DNA

what contains most of a cell’s genetic material in the form of DNA

chromosomes

what are genes

the units of inheritance that transmit information from parents to offspring

describe DNA struction and function

• each chromosome has one long DNA molecule with hundreds of thousands of genes

• DNA is inherited by offspring from their parents

• DNA controls the development and maintenance of organisms

  • they tell the cell which proteins to make and how to make them

• each DNA molecule is made up of two long chains arranged in a double helix

• each link of chain is one of 4 kinds of chemical building blocks called nucleotides

what are the 4 bases used in DNA

• A (adenine)

• C (cytosine)

• G (guanine)

• T (thymine)

a type of protein critical to all cells is an organic catalyst called:

enzyme: they increase the rate of biochemical reations occuring in all living cells by lowering the activation energy

genes control proteins production ____

indirectly

• DNA is transcribed into RNA then translated into a protein

what is a genome

the complete set of genetic material in an organism

the human genome and those of many other organism have been sequenced using ____

DNA sequencing machines

high-throughput technology

tests thousands of chemicals interacting a particular type of cell or organism

what is bioinformatics

how computers study our structural information and process a large volume of data

feedback mechanisms allow biological processes to _____

self-regulate

describe negative feedback

as more of a product accumulates, the process that creates it slows and less of that product is produced

• ex. temperature regulation, blood glucose regulation

• happens frequenlty

describe positive feedback

as more of a product accumulates, the process that creates it speeds up and more of the product is produced

• ex. blood clotting, labor contractions during childbirth, lactation

• does not happen as frequently

Theodosius Dobzhansky had stated, “nothing in biology makes sense except in _____

the light of evolution

what is taxonomy

the branch of biology that names and classifies species into groups of increasing breadth

what is the broadest unit of classification

domain

what are the three domains

• all eukaryotic organisms

• bacteria

• archae

the domain eukarya includes three multicellular kingdoms”

• plants

• fungi

• animals

other organisms were formerly grouped into a kingdom called Protista, though these are now often grouped into many separate kingdoms

example of unity found in the diversity of life

• DNA is the universal genetic language common to all organisms

• unity is evident in many features of cell structure

what two main points did Charles Darwin make

• species showed evidence of “descent with modification” from common ancestors

• natural selection is the mechanism behind “descent with modification”

what were some of Darwin’s observations

• individuals in a population have traits that vary

• many of these traits are heritable

• more offspring are produced than survive (natural selection)

• competition in inevitable

• species generally suit their environment

darwin inferred that

• individuals best suited to their environment are more likely to survive and reproduce

• over time more individuals in a population will have the advantageous traits

the natural environment “selects” for beneficial traits

“unity in diversity” arises from _____

“descent with modification”

ex. the forelimb of the bat, human, horse and the whale flipper all share a common skeletal architecture (fossils can help us find evidence of anatomical unity from descent with modification)

true of false

Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species

true

science is derived from latin and means ____

to know

define inquiry

the search for information and explanation

what are the two types of scientific inquiry and define them

• discovery science: describes natural structures and processes (what you observe)

• hypothesis-based science: coming up with potential answers to well-framed questions

data falls into what two categories

• qualitative: descriptive, characteristic like color

• quantitative: recorded measuremnts, numbers

discovery science involves inductive reasoning which means

• it draws conclusions from a series of observations

• ex. the sun always rises in the east

observation can lead us to ask questions and propose hypothetical explainations called _____

hypotheses

how can a hypothesis be tested

by observation or experimentation

what is the “if…then” logic of hypothesis based science

• deductive reasoning which uses general premesis to make specific predictions

• ex. if organisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction)

a hypothesis must be _____ and _____

testable, falsifiable

what happens if you fail to falsify a hypothesis

it does not prove the hypothesis

describe a controlled experiment

• compares an experimental group with a control group

• ideally, only the variable of interest differs between the control and experimental groups

• a controlled experiment means that control groups are used to cancel the effects of unwanted variables

• a controlled experiment does not mean that all unwanted variables are kept constant

in science, observations and experimental results must be _____

repeatable

in the context of science a theory is:

• broader in scope than a hypothesis

• general and can lead to new testable hypotheses

• supported by a large body of evidence in comparison to a hypothesis