Chapter 1 Flashcards
The Scientific Study of Life
Biology
The scientific study of life
-all forms of life, bacteria to fungi to humans
-also includes interactions between different organisms
-new discoveries every day
Cells
The fundamental unit of life
-all organisms are made of 1 or more cells
-cells are organized into tissues
Prokaryotic cell types
Domain Bacteria and domain archaea
-cells lack nuclei
-most are unicellular
DNA
Deoxyribonucleic acid
-the molecule that carries genetic information
-also passed onto next generation
Protista
multiple lineages
-can be unicellular or multicellular
-can be autotrophs or heterotrophs
Ecosystem
The living and nonliving components of an area (ex. the Savanna)
-ecosystems are organized into a biosphere
Matter
All matter, living and nonliving, is composed of atoms
Atom
The smallest chemical unit of a type of pure substance (element) (ex. a carbon atom)
-atoms are organized into molecules
Molecule
A group of joined atoms (ex. DNA)
-molecules are organized into organelles
Organelle
A membrane-bounded structure that has a specific function within a cell (ex. chloroplast)
-organelles are organized into cells
-all life is composed of cells, although some cells don’t have organelles
Tissue
A collection of specialized cells that function in a coordinated fashion (ex. epidermis of a leaf)
-tissues are organized into organs
Organ
A structure consisting of tissues organized to interact and carry out specific functions (ex. leaf)
-organs are organized into organ systems
Organ system
Organs connected physically and chemically that function together (ex. the above ground part of a plant)
-organ systems are organized into individual organisms
Organism
A single living individual (ex. one acacia tree)
-some organisms are single-celled, like bacteria and amoebas. This means they are composed of just one cell
-other organisms are multicellular (composed of many cells) (ex. sea sponges, moss, mushroom)
-other organisms are composed of tissues (ex. jellyfish and certain worms)
-more complex organisms are composed of tissues, organs, and organ systems (ex. a fish and a tree)
-individual organisms are organized into populations
Population
A group of the same species or organism living in the same place and time (ex. multiple acacia trees)
-populations are organized into communities
Community
All populations that occupy the same region (ex. all populations in the Savanna)
-communities are organized into ecosystems
Biosphere
The global ecosystem
-parts of the planet and its atmosphere where life is possible
Emergent properties
Produces life’s complexities, interaction brain cells have the properties that brain cells itself lack (produces memory). The brain can only do those things when the cells interact with each other
-it arises at every level of biological organization
Primary producers
Also called Autotrophs
-extract energy and nutrients from the nonliving environment (ex. energy from sunlight)
mutation
Changes in an organisms DNA structure
Consumers
Also called heterotrophs
-obtain energy by eating other organisms (ex. eating a plant)
Decomposers
Also called heterotrophs
-consumers that obtain nutrients from dead organisms and organic waste (ex. mushroom obtains nutrients from a dead leaf)
-multicellular (mushrooms)
-unicellular (yeast)
Adaptation
An inherited characteristic or behavior that enables an organism to survive and reproduce successfully in its environment
Energy transfers
They are never 100% efficient, some energy is always lost in the form of heat to the surroundings
-no organism can use heat as an energy source, it represents a permanent loss from the cycle of life
Homeostasis
The process by which a cell or organism maintains internal equilibrium (ex. thermostat: senses temperature change in the environment and adjusts heat to a consistent temperature)
-Many organisms control their body temperature (ex. sweating)
Asexual reproduction
Only one parent is involves and the offspring are genetically identical to the parent
-A successful strategy in unchanging environment (ex. strawberry plant: plantlets are identical to the parent plant)
Sexual reproduction
Two parents involved and offspring are genetically different from both parents
-a successful strategy in changing environments, since offspring are unlike either parent
-most plants and animals reproduce sexually (ex. baby swan received genetic material from both parents)
Growth
An increase in an organism’s size, usually by way of cell division
Development
Changes that occur as an organism matures, including growth, cell specialization, and other procedures
Evolution
Genetic changes over time in a population
-Pigmy seahorse blends into its coral habitat. It’s well hidden from predators so it survives and them passes its genes onto the next generation
Environment “selects” beneficial adaptations- Bacteria example
Bacteria reproduce and evolve quickly example
-this population has a randomly occurring genetic variation
-the red cells have a different gene than the green cells, making them resistant to the effects of the antibiotics
-antibiotics kill of most of the green bacteria, the resistant bacteria survives (red ones)
-antibiotic resistant bacteria are most successful when antibiotics are present
All life share 5 characteristics
-organization
-energy use
-internal consistency (homeostasis)
-reproduction, growth, and development
-evolution
Taxonomy
The science of classification
-scientists use it to name and classify organisms
-broad levels: domain and kingdom
The tree of life includes 3 main branches (domains)
-domain bacteria
-domain archaea
-domain eukarya
Domains are divided into kingdoms
All 3 domains include 1 or more kingdoms, or lineages, representing thousands to millions of different species
Domain Eukarya
Organisms that have larger, more complex cells with nuclei
-animals are a familiar group of eukaryotes, including vertebrates like fish, frogs and mammals, as well as invertebrates such as bees
Protists
Most diverse group of eukaryotes, with multiple lineages, including amoebas, slime molds, algae, and other species
Kingdom animalia
Multicellular and heterotrophs (by ingestion)
Kingdom fungi
Most are multicellular and heterotrophs (by external digestion)
Kingdom plantae
Multicellular and autotrophs
Steps of the Scientific Method
-make observations
-ask a question
-consult prior knowledge
-formulate hypothesis
-design experiment
-collect and interpret data
-consult prior knowledge
-draw conclusions
-peer review
-publish
Observations and questions (scientific theory)
What we see, hear, smell, read, etc. Questions to build on existing knowledge. Finding connections between unrelated observation advances tremendously
Hypothesis and prediction (scientific theory)
A tentative explanation for an observation. A testable idea of how to answer a question
-prediction allows you to test the hypothesis in a controlled environment
Data and conclusion (scientific theory)
Scientists use the data from the experiments to draw conclusions about the hypothesis
-data can either support of falsify a hypothesis
Review and publish (scientific theory)
When there’s enough data to convincingly support or falsify a hypothesis, scientists submit a manuscript. Each submission is reviewed by experts in that field. I fit is accepted, it is published in a peer-reviewed journal
Three types of variables (scientific theory)
-independent variable
-dependent variable
-standardized variable
Independent variable (scientific theory)
What is manipulated
Dependent variable (scientific theory)
What is measured
Standardized variable (scientific theory)
What is held constant for all subjects
Control group (scientific theory)
Baseline used of comparison
Experimental group (scientific theory)
Group that may or may not show different results from the control group
Theory definition (scientific theory)
A broad explanation for a natural phenomenon (based on years and years of data, collected in hundreds of different experiments
Species
The basic unit of classification
-closely related species are grouped into the same genus
How do scientists chose names of species with taxonomy?
Genus and a specific descriptor denote the 2-word scientific name of each species
-human: Homo sapiens (Genus name is capitalized and scientific description name is italicized)
Experiment (scientific theory)
An investigation carried out in controlled conditions
Variable (scientific theory)
A changeable element of an experiment
Placebo (scientific theory)
An inert substance that resembles a treatment given to the experimental groups
Sample size (scientific theory)
The number of individuals assigned to each treatment (or to a control group)
-The bigger the sample size, the more accurate the data will be
Fact (scientific theory)
A repeatable observation that everyone can agree on
Nonliving things that have 2/5 life characteristics
-House: structurally organized and maintains a consistent temperature
-Car: organized and requires energy
