Chapter 1 - Defining and Classifying Life

Prokaryotic cells

oldest, most primitive cells. No membrane bound organelles. DNA not housed in nucleus. Often much smaller

Where are prokaryotic cells found

bacteria and archaea

Eukaryotic cells

more complex, many membrane bound organelles, DNA housed in nucleus, larger

Where are Eukaryotic cells found

animals, plants, fungi, protists

How long ago was the probable origin of the earth

~4.6 BYA

How long ago did prokaryotes appear

~3.8 BYA

How long ago did eukaryotes appear

~1.7 BYA

How long ago did the oldest human ancestors live

~6-7 MYA

How long ago did Genus Homo Evolve

~2 MYA

How long ago did modern humans (Homo sapiens) first arrive

200,00 YA

Signs of life

metabolism

composed of cells

homeostasis

respond to stimuli

growth and reproduction

contain RNA and DNA

evolution

Hierarchy of Life: Taxonomy

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Binomial Nomenclature

universal way of naming all living organisms using 2 word latin names. Composed of the genus and species.

ex. Homo sapien

The 3 Domain System

Bacteria: single cell, no nucleus, prokaryotic cells

Archaea: primitive single cells, no nucleus, live in extreme conditions, prokaryotic cells

Eukarya: all have eukaryotic cells

4 kingdoms in Domain Eukarya

protists, fungi, plantae, animalia

Defining traits of Protists

Single-celled, no cell wall, heterotrophs & autotrophs

Defining traits of Fungi

multicellular, cell wall, saprotrophs

Defining traits of Plantae

multicellular, cell wall, autotrophs

Defining traits of Animalia

multicellular, no cell wall, heterotrophs

Defining human traits

bipedalism

opposable thumbs

large brain to body ratio

complex languages

culture, morality, emotions

What would an E.T. notice if they came to our planet

Density of population

large geographical range

control or large flows of energy

global impact

powers of communication and art making

Why can we only support hypothesis, not prove anything?

Our understanding and technology is always changing making it impossible to definitively prove anything in science

Limits of science

Soma data is hard to obtain (non-physical events, not enough subjects)

Limited testing on humans (not all humans react the same)

Independent Variable

the variable under study by the scientist

Dependent variable

the variable that is expected to change as a result of the independent variable

Standardized variables

all other variables in the experiment

Sample size

number of subjects included in the study

Experimental group

the group receiving the variable(s) being tested

Control Group

The standard group to which comparisons are made during an experiment