The Scientific Study of LifeIntroductionChapter 1

Biosphere

EcosystemFlorida coast

CommunityAll organisms onthe Florida coast

PopulationGroup of brown

pelicans

Nucleus

Nerve

Spinal cord

CellNerve cell

TissueNervous tissue

OrganBrain

Organelle

NucleusMolecul

eDNA

Atom

Organism Brown pelican

Organ systemNervous system

Brain

Life’s Levels of

Organization

How do we study life?

Discovery Science & Hypothesis-driven

Controlled Experiment

Observations

Questions

Hypothesis

Prediction

Experiment

Evaluate

Peer Review

Control GroupExperimental

Group

Independent Variable

Dependent Variable

Placebos

refers to a treatment known to be without effect; usually used to

compare against a potential effective

medicine

To study life, one must define life……

What do all living things

have in common

?

• Order– Structure/Function– Basic building

block: the CELL

To study life, one must define life……

What do all living things

have in common?

To study life, one must define life……

What do all living things

have in common?

• Regulation– Maintain

homeostasis(stability during

changing external conditions)

To study life, one must define life……

What do all living things

have in common?

• Growth & Development• Unique to

every species

To study life, one must define life……

What do all living things

have in common?

• Energy UtilizationTake in energy &

transform it to perform all life function

To study life, one must define life……

What do all living things

have in common

?

• Respond– react to

environmental stimuli

To study life, one must define life……

What do all living things

have in common

?

• Reproduction– Continues the

species as a whole (otherwise

→extinction)

– Is it necessary for the individual organism?

To study life, one must define life……

What do all living things

have in common

?

• Evolution– Species’ capacity

to change over time

This is not an individual

characteristic!

• NUTRITION• TRANSPORT• RESPIRATION• EXCRETION• SYNTHESIS• GROWTH & REPAIR• REGULATION• REPRODUCTION

What are the life processes?

Every living thing must carry out these

functions,

but

do they complete them in the same

way?

Can you define these terms scientifically?

If something is living, it will perform all of the Life Activities

Do all organisms carry these activities out in the same way? Use your textbook or internet to help you define

these activities in your own words.

The source of life’s connections?

What was the first living thing and how did we get

tother

e

Here

Evolution by means of Natural

SelectionTwo points: 1. Species arise through a

process of descent with modification

2. Natural Selection

Darwin Published his book:

Population with varied inherited traits

1

Elimination of individuals with certain traits

2

Reproduction of survivors3

Heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others

The best adapted

survive to reproduce and pass on their

“fit” genes.

Each adaptation creates a web of interactions that

support one another on a larger scale….

Ecosystem

Producers(such as plants)

Sunlight

Cyclingof

chemical

nutrients

Chemical energy

Consumers(such as animals)

Heat

Heat

Flow of

Energy

Classifying life further...

Delightful King Philip Came Over For Good Soup

Ursus arctos

Ursus maritimus

Ursus americanus

Cryphia muralis

Cryphia algae

Cryphia domestica

Cryphia cuerva

SPECIESa group of organisms capable of

interbreeding and producing fertile, viable offspring in

nature.

Canis familiaris

More than 800 dog breeds exist. All part of the same species.

DELIGHTFUL KING PHILIP CAME OVER FOR GOOD SOUP

HOW TO REMEMBER ALL THE GROUPS:

3 domains

Three Domains

• “Super Kingdoms”• Highest level of classification• Least specific

Domains

Eubacteria Archaeabacter

iaEukarya

Three Domains

Bacteria = Prokaryotes

●LIVE IN UNUSUALLY HARSH ENVIRONMENTS

●Extremophiles, Prokaryotes●This is the Proposed 6th

KINGDOM◦There are 3 types:

⚫Salt-loving, heat/cold-loving

& methane-loving

Archaea (pronounced: R-Key-uh)

Methanogens Halophiles Thermophiles

Archaebacteria

Domain Eubacteria • “common”

bacteria• Least like us• Prokaryotes• Peptidoglycan Cell

Wall• Some may have:

– Slime Layers– Flagella– Pilli

Magnetosomes• Chains of

membranous prokaryotic organelles in magnetotatic bacteria

• Acts like a compass needle

• Orients bacteria based on magnetic field!

Eukaryotes

Domain Eukarya

KINGDOMSwithin Eukarya

Thanks Terri Lester for the awesome slides!

●NOT a plant & CANNOT make their own food. NOT a scavenger●examples include yeasts, molds, and

mushrooms

●absorb decaying, digested food from the external environment

KINGDOM FUNGI

• multicellular - possess chloroplasts and cell walls

• make their own food – PHOTOSYNTHESIS • Reproduce sexually – can be asexual

Kingdom Plantae

The two main plant divisions are the bryophytes and the tracheophytes.

moss

sunflower

BRYOPHYTESthe non-vascular plants

low growingno “true” stems or leaves

liverwort hornwortmoss

TRACHEOPHYTESthe vascular plants

tall growing plants

contain xylem for transport of water

contain phloem for transport of sugar

●multi-cellular organisms which ingest their food – HETEROTROPHS

●Most (not all) reproduce sexually

Kingdom Animalia

• not classified• contain genetic

material (DNA) but lack cell structures

• only carry on the life function of

reproduction BUT must have a host to be able to reproduce

• Debatable!!

Viruses

Papillomavirus

BacteriophagesPOLIO VIRUS

Bacteriophages

Category Human Chimpanzee Dandelion Housefly

KINGDOM Animalia Animalia Plantae Animalia

PHYLUM Chordata Chordata Tracheophyta

Arthropoda

CLASS Mamalia Mamalia Angiospermae

Insecta

ORDER Primate Primate Asterales Diptera

FAMILY Hominidae

Pongidae Compositae Muscidae

GENUS Homo Pan Taraxacum Musca

SPECIES Homo sapien

Pan troglodytes

Taraxacum officinale

Musca domestica

●Predominately unicellular organisms (with exceptions – colonial without tissue)

●Either plant-like, fungus-like or animal-like characteristics

●Ex: protozoans and some algae– true nucleus and nuclear membrane

●Classification of Protists: – Motile – Divided based on their means of

LOCOMOTION Mode of Nutrition, or Life Cycle

Kingdom Protista

Protists move about using flagella, cilia or pseudopods.

Trypanosomes are human parasites that cause African sleeping sickness

(transmitted by tsetse flies)

Euglena are photosynthetic protists.

Paramecia and Stentorare common pond water organisms.

These protists are food for many other organisms.

brain eating pond organism

causes dysentery

Amoeba proteus

DIATOMS are ocean dwelling protists that make up PLANKTON.

PLANKTON is food for ocean dwelling organisms!

Animal-like Protists • Often animal-like Protists are called PROTOZOA• Live in fresh or salt water, in the soil, or in the

bodies of other organisms• No Cell Wall!Fungus-like Protist• Heterotrophs with Cell Wall• Reproduce through spores• Mold & MildewPlant-like Protists:• Plant-like protists include algae, diatoms and

many others• They contain chloroplasts and are therefore

AUTOTROPHIC• Cell Wall present• Important to the aquatic food chain

The Euglena: clip●exhibits both animal-like and Plant-

like characteristics●contains chloroplasts, which are

involved in PHOTOSYNTHESIS●contains a flagellum, which is used

for LOCOMOTION●autotrophic or heterotrophic

depending on the availability of light

Plant and Animal-like Protist

Kingdom Animalia

Animal Evolution

• Heterotrophs– must ingest others for

nutrients• Multicellular

– complex bodies• No cell walls

– allows active movement• Sexual Reproduction

– Most, not all…• Evolved from colonial

protists

Animal Characteristics

Porifera

Cnidaria Platyhelmint

hessponges

jellyfish

flatworms

roundworms

Nematoda Mollusc

aArthropoda

Chordata

Annelida

Echinodermata

mollusks

multicellularity

Ancestral Protist

tissues

bilateral symmetry

body cavity

segmentation

Animal Evolution

coelom

starfish

vertebrates

endoskeleton

segmentedworms

insectsspiders

specialization & ↑ body complexity

specialized structure & function,muscle & nerve tissue

distinct body plan; cephalization

↑ body complexity↑ digestive & repro sys

↑ digestive sys

↑ body size

redundancy,specialization, ↑

mobility

↑ body & brain

size, ↑ mobility

radial

bilateral

Yellow boxes = examples

© explore bio co.

• Space for organ system development– increase digestive &

reproductive systems• increase food capacity &

digestion• increase gamete production

• Coelem– allows complex structures

to develop in digestive system• ex. stomach

Body Cavity

protostome vs. deuterostome

• Examples:– Sponges

• Body Plan: • no distinct tissues or organs [acoelomate]• do have specialized cells

• Symmetry:• Some are radial symmetric, some asymmetric

• Misc.• sessile (as adults)

Invertebrate: PoriferaVideo

• Examples:– Jellyfish, hydra, sea

anemone, coral• Body Plan:

• tissues, but no organs [acoelomate]

• two cell layers• Symm:

• radial symmetry• Misc.

• Predators• extracellular

digestion– release enzymes

into gut cavity– absorption by cells

lining gut

Invertebrate: CnidariaVideo

Polyp v. Medusa

Body Symmetry

Name that symmetry…

• “Flatworms”– Examples:

• tapeworm, planaria– Misc.

• mostly parasitic– Body Plan

• bilaterally symmetrical• have right & left & then have

head (anterior) end & posterior end – cephalization = development of brain– concentration of sense organs in head– Incomplete digestive tract

• increase specialization in body plan

Invertebrate: Platyhelminthes

acoelomate

Video

• “Roundworms”– Symm.

• bilaterally symmetrical– Body Plan

• pseudocoelom = simple body cavity• digestive system

– tube running through length of body (mouth to anus)– Misc.

• many are parasitic– hookworm

Invertebrate: Nematoda

C. elegans

Video

• Mollusks– Examples

• slugs, snails, clams, squid– Symm.

• bilaterally symmetrical (with exceptions)

– Body Plan• soft bodies, mostly protected by hard shells• true coelem• increases complexity & specialization of internal organs

Invertebrate: MolluscaVideo

• Segmented worms– Examples:

• earthworms, leeches– Body Plan:

• segments• increase mobility• redundancy in body sections• true coelem

– Symm:• bilaterally symmetrical

Invertebrate: Annelida

Video

• Example– Spiders, insects, crustaceans

• Misc.– most successful animal phylum

• Body Plan– bilaterally symmetrical– True Coelom– segmented

• specialized segments• allows jointed appendages

– exoskeleton• chitin (carbohydrate)

+ protein

Invertebrate: ArthropodaVideo

Spider

I wonder why they are so successful….

Arthropod groups

insects6 legs, 3 body parts

crustaceansgills, 2 pairs antennaecrab, lobster, barnacles, shrimp

arachnids8 legs, 2 body partsspiders, ticks, scorpions

Spider

© Ex. Bio Co.

• Starfish, sea urchins, sea cucumber– radially symmetrical as adults– spiny endoskeleton– deuterostome

Invertebrate: Echinodermata

Video

• Which group includes snails, clams, and squid?• Which group is the sponges?• Which are the flatworms?

…segmented worms?…roundworms?

• Which group has jointed appendages & an exoskeleton?

• Which two groups have radial symmetry?• What is the adaptive advantage of bilateral

symmetry?• Which group has no symmetry?

Invertebrate quick check…Invertebrates: Porifera, Cnidaria, Platyhelminthes,

Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata

© Explore Bio Co.

• Features– Dorsal, hollow nerve cord– Notochord– Pharyngeal slits – Post-anal tail

• Most (not all) are VERTEBRATES– Ex. of invertebrates

chordates: tunicates and lancelets

Chordata

Segmented backbone

Cartilaginous rod for support for the body

tunicate video

Chordata: invertebrates

• Examles– fish, amphibians, reptiles, birds,

mammals• Body Plan:

– internal bony skeleton [endoskeleton]– backbone encasing

spinal column– skull-encased brain

• Development– deuterostome

Chordata Vertebrates

© Explore Bio Co. and Pearson Education

• Characteristics – body structure

• bony & cartilaginous skeleton• jaws & paired appendages (fins)• scales

– body function• gills for gas exchange• two-chambered heart;

single loop blood circulation• Ectotherms: control body heat externally

– reproduction• external fertilization• external development in

aquatic egg

Vertebrates: Fish

salmon, trout, sharks450

mya

gills

body

Flying Fish Video © Explore Bio Co. and Pearson Education

Evolution of tetrapodsfour limb vertebrates

Transition to Land

Tibia

Femur

Fibula

Humerus

Shoulder

RadiusUln

a

Tibia

Femur Pelv

is

Fibula

Lobe-finned fish

Humerus

Shoulder

Radius

Ulna

Pelvis

Early amphibian © Explore Bio Co. and Pearson Education

lung

buccalcavity

glottisclosed

• Characteristics – body structure

• legs (tetrapods)• moist skin

– gas exchange

– body function• lungs (positive pressure) &

diffusion through skin for gas exchange• three-chambered heart;

veins from lungs back to heart• ectotherms

– reproduction• external fertilization• external development in aquatic egg• metamorphosis (tadpole to adult)

Vertebrates: Amphibian

frogssalamander

s toads350 mya

lungs

body

heartBull frog vide

o

© Explore Bio Co. and Pearson Education

• Characteristics – body structure

• dry skin, scales, armor– body function

• lungs for gas exchange• thoracic breathing; negative pressure• three-chambered heart• ectotherms

– reproduction• internal fertilization• external development in

amniotic egg

Vertebrates: Reptiles

250 mya

dinosaurs, turtles lizards, snakes

alligators, crocodile

embryo

leatheryshell

chorion

allantois yolk

sac

amnion

lungs

body

heart

Crocodile Video

© Explore Bio Co. and Pearson Education

• Characteristics – body structure

• feathers & wings• thin, hollow bone;

flight skeleton– body function

• very efficient lungs & air sacs• four-chambered heart• endotherms

– reproduction• internal fertilization• external development in

amniotic egg

Vertebrates: Birds (Aves)

150 mya

finches, hawk

ostrich, turkey

trachea

anteriorair sacs

lung

posteriorair sacs

lungs

body

heart

heart

Bald Eagle

musclescontract

diaphragmcontracts

• Characteristics – body structure

• hair• specialized teeth

– body function• lungs, diaphragm; negative pressure• four-chambered heart• Endotherms

– [internal control over body temperature]

– reproduction• internal fertilization• internal development in uterus

– nourishment through placenta• birth live young• mammary glands make milk

Vertebrates: Mammals

220 mya / 65 mya mice, ferret elephants,

batswhales, humans

lungs

body

heart

heart

Elephant Video © Explore Bio Co. and Pearson Education

• Sub-groups – monotremes

• egg-laying mammals• lack placenta & true nipples• duckbilled platypus, echidna

– Marsupials video• pouched mammals

– offspring feed from nipples in pouch• short-lived placenta• koala, kangaroo, opossum

– placental• true placenta

– nutrient & waste filter• shrews, bats, whales, humans

Vertebrates: Mammals

© Explore Bio Co. and Pearson Education

Genus species

Genus species

Binomial nomenclature

italics - typed

Underline - handwritten

© Explore Bio Co. and Pearson Education

• Which vertebrates lay eggs with shells?• Which vertebrates are covered with scales?• What adaptations do birds have for flying?• What kind of symmetry do all vertebrates

have?• Which vertebrates are ectothermic and which

are endothermic• Why must amphibians live near water?• What reproductive adaptations made

mammals very successful?• What characteristics distinguish the 3 sub-

groups of mammals?

Vertebrate quick check…

© Explore Bio Co. and Pearson Education