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Lecture Presentations by Carol R. AndersonWestwood College, River Oaks Campus

© 2014 Pearson Education, Inc.

BIOLOGY Life on Earth WITH PHYSIOLOGY Tenth Edition

Audesirk Audesirk Byers

1An Introduction to Life on Earth

*modified by Misty Lawrence

http://www.mediaresource.org/instruct.htm


Chapter 1 At a Glance

1.1 What Is Life?

1.2 What Is Evolution?

1.3 How Do Scientists Study Life?

1.4 What Is Science?


1.1 What Is Life?

Biology comes from the Greek words “bio” meaning “life” and “logy” meaning “the study of.” Organisms share common characteristics that, taken together, define life. Organisms:


1.1 What Is Life?

The ________ is the basic unit of life

– It is separated from its surroundings by a membrane

– It encloses a variety of structures and chemicals in a fluid environment


• Figure 1-1 The cell is the smallest unit of life

organelles

nucleus

cell wall

plasmamembrane


1.1 What Is Life?

Organisms acquire and use materials and energy

– Materials and energy are required for organisms to maintain organization, to grow, and to reproduce

– Important materials (minerals, water, & other simple chemical building blocks) are acquired from the air, water, soil, and bodies of other living things

– Organisms use energy continuously to sustain themselves


• Figure 1-2 Properties of life

Eggs: livingthingsreproduce

Gut: livingthings acquirenutrients

Antennae andeyes: livingthings respondto stimuli


1.1 What Is Life?

Organisms acquire and use materials and energy (continued)

– Organisms obtain energy in two ways, coming directly or indirectly from the sun

– ________________ is the process by which plants and some single-celled organisms capture sunlight

– Other organisms consume energy-rich molecules in the bodies of other organisms


• Figure 1-3 The flow of energy and the recycling of nutrients


1.1 What Is Life?

Organisms actively maintain organized complexity

– Living things use energy on a continuous basis to self-sustain

– Cells pump chemicals in and out for appropriate chemical reactions to occur

– Organisms maintain relatively constant internal conditions or _______________-


• Figure 1-4 Organisms maintain relatively constant internal conditions

What does your body do to try to maintain

homeostasis when you are physically active?


1.1 What Is Life?

Organisms perceive and respond to stimuli

– Organisms sense and respond to internal and external environmental stimuli

– Sensory organs in animals can detect and respond to external stimuli such as light, sound, chemicals, etc.

– Internal stimuli in animals are perceived by stretch, temperature, pain, and chemical receptors

– Plants and bacteria respond to stimuli as well (e.g., plants grow toward the light, and bacteria move toward available nutrients in a medium)


1.1 What Is Life?

Organisms grow

– Every organism becomes larger over time

– Plants, birds, and mammals grow by producing more cells to increase their mass

– Bacteria grow by enlarging their cells; they divide in half to reproduce after genetic material is copied

– Growth involves the conversion of acquired materials to molecules of the organism’s body


1.1 What Is Life?

Organisms reproduce

– Organisms reproduce by:

–

–

–

–

– Organisms give rise to offspring of the same type

– The parent’s genetic material (___) is passed on to the offspring, creating continuity of life


• Figure 1-6 Organisms reproduce

Dividing Streptococcusbacterium

Panda with its babyDandelion producingseeds


1.1 What Is Life?

Organisms, collectively, have the capacity to evolve

– Evolution is the process by which modern organisms descended, with modifications, from preexisting forms of life

– Changes in DNA within populations occur over the course of generations, which results in evolution

– Populations are



Evolution explains the diversity of life on Earth

Evolution provides an explanation for the similarities found among different types of organisms

– Chimpanzees and people have various physical features in common

– DNA of humans differs from that of chimpanzees by less than 5%


• Figure 1-8 Chimps and people are closely related



Three natural processes underlie evolution

–

–

–



Mutations are the original source of differences in DNA

– Variations are due to the differences in genes, which are components of DNA and the basic units of heredity

– ___________ occur when changes in genes are mistakenly copied

– Mutations can also result from DNA damaged by

– UV rays from sunlight and toxic chemicals



Some mutations are inherited

– Occur in sperm or egg cells

– Effects of mutation

– No effect (harmless)

– A decrease in the organism’s ability to function

– Death of the organism

– An increase in an organism’s ability to survive and reproduce (rare)



Some inherited mutations help individuals survive and reproduce

– ________ ________is the process by which organisms with certain inherited traits survive and reproduce better than others in a particular environment

– Organisms that best meet environmental challenges leave the most offspring

– Natural selection preserves genes that help organisms flourish



Some inherited mutations help individuals survive and reproduce (continued)

– Adaptations are structures, physiological processes, or behaviors that aid in survival and reproduction

– Adaptations that are good for one environment may be poor in another (Can you give an example?)

– Species that cannot adapt to environmental change become extinct, as for example, the dinosaurs

– Extinction is the


Levels of biological organization

Fig. 1-10



Life can be studied at different levels

– All matter is formed of elements

– An atom is the smallest _____ _____ _____ retaining the properties of an element

– Atoms combine to form molecules

– Molecules provide the building blocks for cells, the smallest _______ ___ ______



Life can be studied at different levels (continued)

– Some forms of life consist of single cells

– In multicellular forms, cells combine to form tissues

– Tissues combine to form organs, which can be united as organ systems

– Multicellular organisms are composed of multiple organ systems



Life can be studied at different levels (continued)

– Organisms of the same type that are capable of interacting and interbreeding are called a species

– A group of organisms of the same species living in a given area is a population

– Interacting populations make up a community

– A community and its nonliving environment is an ecosystem

– The entire surface of Earth, including living and nonliving components, is the biosphere



Biologists classify organisms based on their evolutionary relationships

– Scientists generally categorize organisms into three major groups, or domains

–

–

–

– The fundamental differences among cell types in organisms are reflected in classifications


• Figure 1-11 The domains and kingdoms of life

FIRST CELLS

DO

MA

IN B

AC

TE

RIA

Protists

DO

MA

IN E

UK

AR

YA

DO

MA

IN A

RC

HA

EA

Plants

Fungi

Animals



Biologists classify organisms based on their evolutionary relationships (continued)

– Bacteria and Archaea are single, simple cells

– Eukaryotic organisms have one or more extremely complex cells

– The domain Eukarya contains four subdivisions or kingdoms

–

–

–

–



Biologists classify organisms based on their evolutionary relationships (continued)

– There are exceptions to any simple set of rules used to distinguish the domains and kingdoms, but three characteristics are particularly useful

– Cell type—simple or complex

– The number of cells in each organism—unicellular or multicellular

– Energy acquisition


• Table 1-1



Cell type distinguishes the Bacteria and Archaea from the Eukarya

–All cells share common features

– Plasma membrane is a thin sheet of molecules surrounding the cell

– Organelles are specialized structures that carry out specific functions

– All cells contain DNA, the hereditary material



Cell type distinguishes the Bacteria and Archaea from the Eukarya (continued)

– The domains Bacteria and Archaea consist of _______________ cells

– The domain Eukarya is composed of ____________ cells




– Two cell types are seen among all living things: prokaryotic and eukaryotic cells

– Cell types are named after presence or absence of a nucleus

– The nucleus is a membrane-enclosed sac containing the cell’s genetic material




– Eukaryotic (“true nucleus” in Greek)

– They are larger than prokaryotic cells

– They contain a variety of organelles, including a nucleus

– This cell type is found only among members of the domain Eukarya

– They are extremely complex




– Prokaryotic (“before nucleus” in Greek)

– They are only 1–2 micrometers in diameter

– They lack organelles enclosed by membranes

– They lack a nucleus

– This cell type is found in the domains Bacteria and Archaea

– They are smaller and much simpler than the eukaryotic cell



Multicellularity occurs only among the Eukarya

– Unicellular (single-celled) organisms are found in

– Bacteria

– Archaea

– Multicellular (many-celled) organisms are found in Eukarya, within the kingdoms

– Fungi

– Plantae

– Animalia



The Eukarya acquire energy in different ways

– Autotrophs (“self-feeding”)

– Photosynthetic organisms that capture sunlight and store it in sugar and fats

– Includes plants, some bacteria, and some protists

– Heterotrophs (“other-feeding”)

– Organisms that acquire energy through ingesting molecules in the bodies of other organisms

– Includes many archaeans, bacteria, protists, fungi, and animals

– The size of the food eaten varies from individual food molecules to ingestion and digestion of whole chunks



Biologists use the binomial system to name organisms

– Organisms are placed in a hierarchy of categories

– Genus and species are the two smallest categories

– Genus includes many different species with similar characteristics

– Species includes organisms that can interbreed and are nearly identical



Biologists use the binomial system to name organisms (continued)

– Binomial system based on Latin words two (bi) and names (nomial), and consisting of the genus and species

– Genus name is capitalized

– Both genus and species names are italicized

– People are ______ __________



Science is the systematic inquiry – through observation and experiment – into the origins, structure, and behavior of living and nonliving environments



Science is based on the principle that all events have natural causes

– The belief that some events happen through supernatural forces (e.g., the actions of Greek gods)

– The belief that all events can be traced to natural causes that we can comprehend (natural causality)

– Corollary: Evidence gathered from nature has not been deliberately distorted to fool us



The scientific method is an important tool of scientific inquiry

Scientific inquiry is a rigorous method for making observations

– The scientific method for inquiry follows six steps



The six steps of scientific inquiry

1. Observation of a specific phenomenon

2. The observation, in turn, leads to a question

3. The question leads to formulation of a hypothesis, based on previous observations, which is offered as an answer to the question



The six steps of scientific inquiry (continued)

4. The hypothesis leads to a prediction, which isthe expected outcome of testing if the hypothesis is correct

5. The prediction is tested by carefully designed additional observations or carefully controlled manipulations called experiments

6. The experiments produce results that either support or refute the hypothesis, allowing the development of a conclusion



Biologists test hypotheses using controlled experiments

– Two types of situations are established

– A baseline or control situation in which all possible variables are held at a constant

– An experimental situation in which one factor, variable, is manipulated to test the hypothesis to determine that this variable is the cause of an observation

– Science is useless unless communicated

– The scientific method is illustrated by experiments by Francesco Redi and Malte Andersson



Scientific theories have been thoroughly tested

– A scientific theory is a general and reliable explanation of important natural phenomena that has been developed through extensive and reproducible observations and experiments

– A scientific theory is best described as a natural law, a basic principle derived from the study of nature, which has never been disproven by scientific inquiry



Scientific theories have been thoroughly tested (continued)

– The cell theory (that all living organisms are composed of cells) and the theory of evolution are fundamental to the study of biology

– Natural causality is the principle that all events can be traced to natural causes

– Natural laws apply to every time and place

– Scientific inquiry is based on the assumption that people perceive natural events in similar ways



Scientific theories have been thoroughly tested (continued)

– New scientific evidence may prompt radical revision of existing theory

– For example, the discovery of prions



Scientific theories involve both inductive and deductive reasoning

– Inductive reasoning is used in the development of scientific theories

– A generalization is created from many observations that support it and none that contradict it

– For example, the theory that Earth exerts gravitational forces on objects began from repeated observations of objects falling downward toward Earth and from no observations of objects falling upward away from Earth



Scientific theories involve both inductive and deductive reasoning (continued)

– Deductive reasoning is the process of generating hypotheses based on a well-supported generalization (such as a theory)

– For example, based on the cell theory, any newly discovered organism would be expected to be composed of cells



Scientific theories are formulated in ways that can potentially be disproved

– Basic principles of science are referred to as theories because theories can be disproved or falsified

– Falsifying theories is distinctly different between scientific theories and faith-based beliefs

– “Each creature on Earth was separately created” cannot be subjected to scientific inquiry because it is a belief rooted in faith



Science is a human endeavor

– Human personality traits are part of “real science”

– Scientists, like other people, may be driven by pride, ambition, or fear

– Scientists sometimes make mistakes

– Accidents, lucky guesses, intellectual powers, and controversies with others contribute strongly to scientific advances

C1 study slides

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