• Q: Is human evolution a ladder with a series of steps leading directly from an anthropoid ancestor to Homo sapiens?

• A: No. It is like a multibranched bush; many splinter groups have traveled down dead ends. Several different human species coexisted. Our species is the tip of the only twig that still lives.

•Examine the above timeline of human evolution.

• Q: Did human characteristics, such as upright posture and enlarged brain, evolve in unison?

• A: No. Different human features evolved at different rates, with erect posture, or bipedalism, leading the way. Ex: We had ancestors who walked upright, but still had ape-sized brains.

• KINDS OF HOMINIDS:

• I. Australopithecus (came before Homo genus) walked African savanna.

• A. afarensis = early species, was bipedal

• One of most complete fossil skeletons of A. afarensis was found (see left); was nicknamed “Lucy” by her discovers.

• (“Lucy in the Sky with Diamonds” song was playing on radio when she was discovered.)

• Was female, 3’ tall, softball size head, 3.2 million years old in East Africa.

• Australopithecus species extinct by 1.4 million years ago.

Lucy

• Hominid bipedal footprints discovered in Tanzania, East Africa in 1978.

• Are 3.7 million years old. Evidence that bipedalism is a very old human trait.

• A. afarensis skull, 3.9 million years old, with a vertical backbone.

• Evidence that upright posture is at least that old..

• II. Homo habilis - (“handy man”) - enlargement of human brain, stone tools. East Africa.

• III. Homo erectus - extension to other continents, change in diet, larger proportion of meat (hunted), taller, larger brain capacity. Caves, built fires, animal skin clothing, refined tools, social cooperation. African, Asian, European, Australian.

• IV.Neanderthals (descendant of H. erectus /early Homo sapien) - Heavier browridges than us, less pronounced chins, brains slightly larger than ours, skilled toolmakers, burials, rituals, abstract thought. “Caveman.” Europe, Middle East, Asia.

• V. Homo sapiens - regionally diverse.

• A. Archaic Homo sapiens. Oldest is over 300,000 years old, Africa. Can include Neanderthals.

• B. Cro-Magnon - like modern humans, caves of France, 35,000 years old.

• C. Homo sapiens sapiens -modern humans

Cro-Magnon www.mos.org/.../fossils/ fossilview.php?fid=55

• What happened to various Homo erectus descendants? 2 Hypotheses:

• 1. Multiregional hypothesis - Modern humans evolved simultaneously in different parts of the world. Accounts for genetic similarity due to interbreeding among neighboring populations.

• 2. “Out of Africa” hypothesis (or “replacement hypothesis”) - Modern humans arose from a single archaic group in Africa. Neanderthals and others outside Africa were evolutionary dead ends. Spread out of Africa about 100,000 years ago. Genetic evidence mostly supports this, from comparing mitochondrial DNA.

Cultural Evolution -• Erect stance - most radical anatomical change in our evolution. Required major remodeling of foot, pelvis, vertebral column.• Enlargement of brain - secondary alteration - made possible by prolonging growth period of the skull and its contents. Lengthens parental care and child’s ability to benefit from experiences of earlier generations.• Culture - transmission of accumulated knowledge over generations by language, both written and spoken.• 3 major culture stages: Nomads, Agriculture, Industrial “However: we are probably no more intelligent than our cave-dwelling ancestors - we just have cumulative experience of hundreds of generations passed along to us by parents, books, electronic media, and YOUR TEACHERS:)” (Do you agree or disagree with that last statement?)

Creations by Cro-Magnon wildlife artists - 30,000 years ago.

Diversity

Classifying the Diversity of Life

• Systematics– reconstructing evolutionary history by studying biological diversity, both past and present.

• Taxonomy – the identification, naming and classification of species

• Why? To provide order, to communicate internationally about a species; common names are

ambiguous.• Carolus Linnaeus(1707-1778) Swedish

physician and botanist - started a two-part name for each species

• (Binomial nomenclature) *Uses Latin• Genus species• Homo sapien (wise man)• Canis lupis• The Genus is capitalized, the species is

lower case. Both are in italics.• )

• Some scientific names…

.• The system also has a hierarchial classification of species into broader and broader groups of organisms.

• KPCOFGS• This system also

reflects the evolutionary history of a species.

• But, historically, species were grouped by their appearance and physical traits.

But now, there is “The Cladistic Revolution”

• The use of DNA, molecules, and computer technology has helped develop a new approach to classifying species.

• Cladistic analysis is the scientific search for clades,

(“branch”), which consist of an ancestor and all its descendants - - a distinctive branch in the tree of life.

* The items in a clade may be species or classes or phyla - - it focuses on the evolutionary innovations that define the branch points in evolution.

• Identifying clades makes it possible to construct classification schemes that reflect phylogeny - (the evolutionary history of a group or species)

• Cladistic analysis is the most widely used method in systemics, but with some dilemmas… (next slide)

How Cladistic Analysis is Shaking Phylogenetic Trees

• A rigid application of cladistic analysis no longer places birds and reptiles in separate classes.

• The strict application of cladistic analysis sometimes produces phylogenetic trees that conflict with classical taxonomy.

• Based on derived characters, crocodiles are more closely related to birds than they are to lizards and snakes!

Cladistic Analysis: Comparison Between an In-group and Out-group

The old way - -The 5 Kingdom Classification System – 1969 by Robert H. Wittaker

Kingdoms

Eubacteria

Archaebacteria

Protist

Plantae

Fungi

Animalia

DOMAIN EUKARYA

DOMAIN ARCHAEA

DOMAIN BACTERIA

Section 18-3

The new way: 3 Domains (see next slide also)

The Three-Domain Classification Scheme

• A Three-Domain System is an alternative to the Five-Kingdom system.

• The three domains include:

• two domains of prokaryotes, the Bacteria, and Archaea, and

• one domain of eukaryotes, called Eukarya.

• Eukarya consists of Fungi, Protists, Plantae, Animalia.

DOMAIN

KINGDOM

CELL TYPE

CELL STRUCTURES

NUMBER OF CELLS

MODE OF NUTRITION

EXAMPLES

Bacteria

Eubacteria

Prokaryote

Cell walls with peptidoglycan

Unicellular

Autotroph or heterotroph

Streptococcus, Escherichia coli

Archaea

Archaebacteria

Prokaryote

Cell walls without peptidoglycan

Unicellular

Autotroph or heterotroph

Methanogens, halophiles

Protista

Eukaryote

Cell walls of cellulose in some; some have chloroplasts

Most unicellular; some colonial; some multicellular

Autotroph or heterotroph

Amoeba, Paramecium, slime molds, giant kelp

Fungi

Eukaryote

Cell walls of chitin

Most multicellular; some unicellular

Heterotroph

Mushrooms, yeasts

Plantae

Eukaryote

Cell walls of cellulose; chloroplasts

Multicellular

Autotroph

Mosses, ferns, flowering plants

Animalia

Eukaryote

No cell walls or chloroplasts

Multicellular

Heterotroph

Sponges, worms, insects, fishes, mammals

Eukarya

Classification of Living Things

Section 18-3

Figure 18-12 Key Characteristics of Kingdoms and Domains

How do you identify an organism in the field with its scientific name??

• Use a taxonomic key! (or a field guide)

• Dichotomous key = 2 opposing statements at a time.

• Always start at the top of the key.

• Try some! Make some!

Protist Kingdom - Ch. 15 p. 311-316

• Droplets of pond water are filled with Protists!• Protists are the first eukaryotes to evolve from prokaryote

(bacteria) ancestors. They are much more complex than prokaryotes.

• Protists are the ancestors to all other eukaryotes – plants, fungi, and animals.

• The fossil record indicates that eukaryotes evolved from prokaryotes (bacteria) more than 1.7 billion years ago.

• How did eukaryotic cells evolve, and

how did their membrane-enclosed organelles evolve?• A widely accepted theory is that eukaryotic cells evolved through a

combination of two processes:

#1: All organelles (except mitochondria and chloroplasts) evolved from inward folds of the plasma membrane of a prokaryotic cell.

# 2: Endosymbiosis • The Endosymbiosis Theory was largely developed by Lynn Margulis of the University of Massachusetts:

“Chloroplasts and mitochondria evolved from small prokaryotes that established residence within other, larger host prokaryotes.”

• Ex : mitochondria ancestors may have been aerobic bacteria that were able to use oxygen to release large amounts of energy from organic molecules by cellular respiration.

• The host cell may have injested these for food; if they remained alive, they continued to perform respiration within the cell.

• Ex: Similarly, chloroplasts may have come to live inside a larger host cell.

• Because almost all eukaryotes have mitochondria but only some have chloroplasts, it is likely that mitochondria evolved first.

• Endosymbiosis eventually became mutually beneficial. How? ____________________

The Diversity of Protists

- Vary in structure and function more than any other group

or organism.

• Most are unicellular, but some are colonial or multicellular.

• Each cell must carry out all the basic functions of an entire organism.

• Four major categories of protists: (are grouped more by their lifestyle than by their evolutionary relationships)

• 1. Protozoans• 2. Slime molds• 3. Unicellular Algae• 4. Seaweeds

1. Protozoans• Ingest food and thrive in all types of aquatic

environments, including wet soil and the watery environment inside animals.

• Include:

• 1) Flagellates: move by means of one or more flagella. Most free-living, but some are parasitic: cause diarrhea (infected drinking water) or sleeping sickness from the tsetse fly.

• 2) Amoebas: move by means of pseudopodia

• 3) Forams: move with pseudopodia; flexible

• 4) Apicomplexans: are all parasitic and are named for an apparatus at their apex which is specialized for penetrating host cells. Plasmodium -malaria.

• 5) Ciliates: use cilia to move and feed.

Amoeba

Forams

ApicomplexanCiliate: Paramecium Flagellates

2. Slime Molds

• Resemble fungi in appearance and lifestyle, but are not at all closely related.

• Its filamentous body increases exposure to the environment and facilitates their role as decomposers.

• Ex: In leaf litter and other decaying material on a forest floor.

3. Unicellular Algae

• Photosynthetic protists – have chloroplasts • Support food chains in freshwater and

marine ecosystems. • Are components of plankton - the

communities of organisms, mostly microscopic, that drift or swim weakly near the surfaces of ponds, lakes, and oceans.

• Planktonic algae = phytoplankton• Three groups :• A. Dinoflagellates – Whirling – beating of 2

flagella. Blooms cause red tide; toxins cause massive fish kills, and are poisonous to humans.

• B. Diatoms – glassy cell walls with silica, used to make glass. Make diatomaceous earth, used for filtering material and an abrasive.

• C. Green algae – (see next slide)

Dinoflagellates

Diatoms

C. Green Algae• Named for their grass-

green chloroplasts• Flourish in most freshwater

lakes and ponds • Some species are

flagellated.• Of all photosynthetic

protists, green algae are the most closely related to true plants.

• Volvox is a colony of flagellated cells (the smallest green dots.)

• Daughter colonies (the balls within the balls) can form within parent colonies - are released when parent colonies rupture.

Volvox

4. Seaweeds• Large, multicellular marine algae

• Grow on rocky shores & just offshore

• Have slimy rubbery substances that cushion bodies against waves

• Types based on pigments: green algae, red algae, brown algae

• Harvested for food: soups, wrap sushi. Rich in iodine, but have some polysaccharides humans cannot digest

• Used for thickeners in pudding, ice cream, salad dressing. Used for Gel agar in Petri dishes!

Brown Algae

Fungi Kingdom Ch. 16 p. 334-340

• Fungi rot timbers, spoil food, and afflict humans with athletes foot, skin disorders, & even pneumonia!

• Decompose dead organisms, fallen leaves, feces, and other organic materials. Recycling vital chemical elements back to the environment.

• Are eukaryotes, typically multicellular, and probably more closely related to animals than plants.

Fungal Fairy Ring

More Fungi…

• Are heterotrophs that require their nutrients by absorption.

• Digest food outside the body by secreting powerful hydrolytic enzymes into the food and absorb the decomposed nutrients from the surrounding medium.

• Parasitic fungi absorb nutrients from the cells of living hosts.

• Some fungi, such as species infecting human lungs are pathogenic. Orange being Decomposed

By Fungi

Fungi: Structure and Function• Are structurally adapted for their

absorptive nutrition.

• Bodies constructed of structures called hyphae, minute threads composed of tubular walls, surrounding plasma membranes, and cytoplasm.

• Hyphae form an interwoven mat called a mycelium, which is the feeding network of a fungus.

• Fungal mycelium can be huge, but most escape our notice because they are often subterranean.

• The mycelium of one humongous fungus in Oregon is 3.4 miles in diameter and spreads through 2,200 acres of forest. The fungus is at least 2,400 years old and hundreds of tons in weight, qualifying it among Earth’s oldest and largest organisms!

Reproduction in Fungi:

• Reproduce by releasing spores that are produced either sexually or asexually.

• Number of spores can be in the trillions.

• Carried by wind or water, spores germinate to produce mycelia if they land in a moist place where there is food.

• Airborne spores have been found more than 160 km (100 miles) above Earth.

Mushroom Gills containing Basidia

What good is a fungus?• Used by humans in various ways for

centuries: we eat some fungi (mushrooms)

• Add them to dough to make bread rise(yeast)

• Culture them in milk to produce a variety of cheeses (blue cheese)

• Use them to ferment beer and wine (yeast)

• Morals and truffles are a delicacy• Used to produce antibiotics and

other drugs (penicillin, sulfa)• Mycorrhizae – partners with plants. • Fungi play a vital role on earth!• What is a lichen? ___________

Penicillin

Truffles

Blue CheeseQ: What did the female mushroom say to the male mushroom?

A: You’re a fun guy!

Animalia Kingdom• Eukaryotic, multicellular,

heterotrophic organisms that obtain nutrients by ingesting, eating food.

• Digest their food within their bodies after ingesting other organisms, dead or alive, whole or by piece.

• Most reproduce sexually. The zygote develops into a blastula, usually a hollow ball of cells.

• In most animals a gastrula develops next. The gastrula has layer of cells that will form adult body parts and a primitive gut.

• A larva is a sexually immature form of an animal which goes through larval stages

• A change of body form called metamorphosis, eventually remodels the larva into adult form.

The Evolution of Multicellularity:• Animals probably evolved from a colonial, flagellated protist that lived in

Precambrian seas.• By the late Precambrian animals were already diverse.• At the beginning of the Cambrian period, animal diversity exploded. • Over about 10 million years ago, all the major animal body plans

existing today evolved.

Early Animals and the Cambrian Explosion:

• In the last half-billion years, animal evolution has mainly generated new variations of old “Designs” that originated in The Cambrian Seas.

• This “explosion of diversity” in the Cambrian period marked the fossil record as the beginning of the Paleozoic era.

• The “explosion” could be due to increasingly complex predator-prey relationships that led to diverse adaptations for feeding, motility, and protection. (ex: shells or hard outer skeleton evolved vs. earlier soft-bodies)

• Or, the explosion could be due to variation in how and when, and where genes that control the development of animal form are expressed. (ex: placement of body parts in embryos can produce major differences in the phyla)

The Cambrian Seas

Animal Phylogeny -To reconstructthe evolutionary history of animal phyla, researchers must depend mainly on clues from comparative anatomy and embryology.

-This diagram represents one set of hypotheses about the evolutionary relationships among nine major animal phyla. -The circled numbers on the tree highlight four key evolutionary branch points. (see next 3 slides for explanations)

Body Symmetry:

• Radial Symmetry- animals that are arranged around a central axis. A single cut through the middle of the organism in any direction should produce two equal halves.

• Bilateral Symmetry-A single longitudinal cut in only one direction will produce two equal halves

Body Cavities -a fluid-filled space separating the digestive tract from the outer body wall. (body cavity = coelom or gut)• Functions:

• Its fluid cushions the suspended organs to prevent internal injury

• It enables internal organs to grow and move independently of the outer body wall; makes exercise not harmful to internal organs

• In soft-bodied animals (earthworms) it functions as a hydrostatic skeleton against which muscles can work. (ex: for burrowing)

• Ex: Flatworms lack a body cavity = Acoelomate

• Ex: Roundworms have a body cavity partially lined by mesoderm (middle layer of tissue) = Pseudocoelomate

• Ex: Earthworms have a body cavity completely lined by mesoderm = Coelomate

Details of embryonic development:

• Of the animals with a true coelom, there are 2 branches :

• Branch 1: mollusks, annelids, arthropods: mouth develops first in embryo = Protostomes.

• Branch 2: echinoderms and chordates: anus develops first in embryo = Deuterostomes.

Animalia Kingdom -8 Major Invertebrate Phyla:

• Porifera• Cnidaria• Platyhelminthes• Nematoda• Mollusca• Annelida• Arthropoda• Echinodermata

Invertebrates, animals without backbones, represent more than 95% of the animal kingdom!

Sea Anemone: Which Phylum?__________________________

1. Phylum Porifera - Sponges• Sponges are sessile.• Sponges are the simplest

animals, probably evolved very early from colonial protists

• Range in height from about 1 cm to 2 meters.

• Have no nerves or muscles, and consist of about 9,000 species.

• About 100 species lives in fresh water and the rest are marine.

• The body of a sponge resembles a sac perforated with holes.

Sponges Feeding Method:

• Most sponges feed by collecting bacteria from the water which streams through their porous bodies(filter feeding).

• Flagellated cells called choanocytes trap bacteria in mucus and then engulf the food by phagocytosis.

• Cells called amoebocytes pick up food from the choanocytes, digest it, and carry nutrients to other cells.

Cnidocytes, and Purple Striped Jellyfish

Jellyfish

How a Cnidocyst Stinging Cell Works

3. Phylum Platyhelminthes-Flat Worms-Tapeworms, Flukes, & Planaria • Flatworms are the simplest bilateral

animals.• Range from about 1 millimeter (mm) to

about 20 meters in length.• Live in marine, freshwater, and damp

terrestrial habitats• Include many parasitic species

including flukes and tape worms.• Tapeworms have a ribbon like body

which can be up to 20m long in humans.

• Lack a digestive tract, so they absorb partially digested food from the intestines of their hosts.

• Humans can become infected with tapeworms by eating undercooked beef.

• Watch 4 minute tape of fisherman with a parasitic friend.

4. Phylum Nematoda-Round Worms

• Roundworms get their common name from the cylindrical bodies tapered at both ends.

• Roundworms are among the most diverse and widespread animals

• Roundworms consist of about 90.000 known species (perhaps 10 times more actually exist).

• Range in length from 1mm to 1 meter,• Live in most aquatic habitats, in wet soil,

and as parasites in the body fluids and tissues of plants and animals.

• Exhibit a complete digestive tract with a mouth and anus.

• Have a body cavity; pseudocoelom.• Humans host at least 50 parasitic species

including: pinworms, hookworms, and the parasite which causes trichinosis.

A free-living roundworm

Nematode

5. Phylum Annelida-Segmented Worms- Earthworms, Polychaetes, & Leeches

• Annelids are worms with body segmentation, the division of the body along its length into a series of repeated parts.

• Annelids consist of about 15,000 species.• Range in length from 1mm to 3 meters

long.• Live in the sea, most freshwater habitats,

and damp soil.• The three major classes of annelids are

earthworms, polychaetes, and leeches.• Farmers value the earthworm because

they eat their way through the soil, extracting nutrients, tilling the soil, and producing castings which improve the texture of the soil.

Giant Earthworm

Darwin estimated that an acre of British farmland has about 50,000 earthworms which produce about 18 tons of castings per year.

Polychaetes and Leeches• Polychaetes are marine; crawl or

burrow in the seafloor.• Polychaetes have segmented

appendages and hard bristles that help the worm move. The appendages also increase the animal’s surface area for gas exchange and elimination of metabolic wastes.

• Leeches include blood-sucking forms, and are mainly free-living carnivores found typically in freshwater.

• Leeches have been used in medicine, until the twentieth century, for blood-letting.

• Leeches are currently used as a source of anticoagulant and to help relieve swelling in reattached fingers and toes.

6. Phylum Mollusca-Snails, Slugs, Clams, Octopuses, & Squid

• Mollusks are soft-bodied animals.• Are usually protected by a hard shell (although slugs, squids, and

octopuses have either reduced shells, most of which are internal or none at all).

• Often feed by using a straplike rasping organ called a radula to scrap up food.

• Consist of about 150,000 species that are primarily marine, although some inhabit freshwater (snails, clams) and some live on land (snails, slugs).

• All mollusks have a similar body plan with three main parts: a muscular foot, usually used for movement, a visceral mass containing most of the internal organs, and a fold of tissue called the mantle that drapes over the visceral mass, and secretes the shell if one is present.

• There are three major classes of mollusks: • Gastropods which include snails and slugs.• Bivalves include clams, oysters, and mussels.• Cephalopods which include squids and octopuses.

Mollusk Examples:

Mollusk Shells

Octopus-Cephalopod

Scallop-Bivalve

7. Phylum Arthropoda-Crustaceans, Millipedes, Centipedes, and Insects

• Arthropods are named for their jointed appendages.• Number more than a billion billion (1018)living individuals.• Include more than 1 million identified species (two out of three)

and are represented in nearly all habitats of the biosphere.• Arthropods are the most successful of all animal phyla as far as

species diversity, distribution, and sheer numbers.• Arthropods are segmented animals with appendages that have

become specialized for a great variety of functions.• Walking• Feeding• Sensory reception• Copulation• Defense• The body of an arthropod is covered by an exoskeleton.• Must occasionally shed it and secrete a larger one =

________________.• Temporarily vulnerable to predators.

4 Main Classes of Arthropods:

• Arachnids: include scorpions, spiders, ticks, and mites

• Crustaceans: include crabs, lobsters, crayfish, shrimps, and barnacles.

• Millipedes: eat decaying plant matter, have 2 pairs of short legs per body segment, and

Centipedes: paralyze prey (cockroaches & flies), have 1 pair of long legs per body segment

• Insects: including bees, grasshoppers, ants, termites, and cockroaches. Outnumber all other forms of life combined.

Crustacean-Lobster

Millipede Arachnid-Spider Insect-Beetle

8. Phylum Echinodermata-Spiny Skin - Seastar, Sand Dollars, & Sea Cucumbers • Echinoderms are named for their

spiny skin.• All echinodems are marine.• Most are sessile or slow moving.

• Lack body segments.• Have an endoskeleton constructed

from hard plates just beneath the skin.

• Have a water-vascular system, a network of water filled canals that circulates water throughout the echinoderm’s body, facilitating gas exchange and waste disposal.

• Have tube feet connected to the water-vascular system for movement.

• Larvae form = bilateral symmetry. Adult form = radial symmetry.

• Share an evolutionary branch with chordates.

Sea Star

Kingdom Animalia –Phylum Chordata Chordate traits:

* dorsal hollow nerve cord

• notochord• pharyngeal slits• post-anal tail• Chordates also show

segmentation; examples are vertebrae and the segmented muscles of all chordates.

Vertebrates – have a backbone7 Classes of Vertebrates:

• Agnatha• Chondrichthyes• Osteichthyes• Amphibia• Reptilia• Aves• Mammalia

Class Agnatha-Jawless Fish

• Agnathans • Lack jaws• Are represented today

by lampreys.• First evolved about 540

million years ago• Are sometimes

parasites that use their jawless mouths as suckers to attach to the sides of large fishes and draw blood.

• 2 chambered heart, ectothermic, scales

Class Chondrichthyes-Cartilaginous Fishes-Sharks, Skates, & Rays

• Have a flexible skeleton made of cartilage.

• Are usually adept predators.• Are often fast swimmers with

streamlined bodies, acute senses, and powerful jaws.

• Sharks do not have keen eyesight, but have an acute sense of smell.

• Sharks consist of fewer than 1.000 living species, nearly all marine.

• Have special electrosensors on the head that can detect minute electrical fields produced by muscle contractions in nearby animals.

• 2 chambered heart, ectothermic

Class Osteichthyes-Bony Fishes• Have a stiff skeleton reinforced

by hard calcium salts.• Are common in the seas and in

freshwater habitats.• Bony fishes have a lateral line

system, a keen sense of smell, and excellent eyesight.

• Have a swim bladder, a gas-filled sac, that helps keep them buoyant.

• A protective flap called an operculum covers a chamber housing gills and moves to help a fish breathe without swimming.

• Sharks lack opercula and must swim to pass water over the gills.

• Bony fish include perch, tuna, and bass.

• 2 chambered heart, ectothermic

Class Amphibia-Amphibians-Frogs, Newts, Toads, & Salamanders

• Amphibians exhibit a mixture of aquatic and terrestrial adaptations.

• Are abundant in damp habitats.• Depend on moist skin to

supplement gas exchange.• Includes frogs, and salamanders.• Typically have a life cycle that

includes metamorphosis • Amphibians consist of only about

8% of all living vertebrates, about 4,000 species.

• Amphibians were the first vertebrates to colonize land and descended from fishes that had lungs and fins, with muscles for support on land

• 3 chambered heart, ectothermic, no scales or claws.

Class Reptilia-Snakes, Liizards, & Turtles• Reptiles include 6,500 species,

mainly snakes, lizards, turtles, crocodiles, and alligators.

• Have scales made of keratin that helps waterproof their skin while on land. Have claws.

• Use lungs and not skin to obtain most of their oxygen.

• Reptiles first evolved amniotic eggs, a water-containing egg enclosed in a shell.

• Reptiles are ectotherms that regulate their internal temperature by behavior, requiring less than 10% of the calories required by a mammal of similar size.

• 3 chambered heart with partial partition, ectothermic.

Mesozoic: Age of the Reptile

• Reptiles were far more widespread, numerous, and diverse during the Mesozoic era, sometimes called the “age of reptiles”.

• Reptiles diversified extensively during the Mesozoic.

• This as the era of the dinosaurs; including the slow moving giants and voracious, two-legged carnivores.

• The age of the reptiles began to wane about 70 million years ago. The global climate cooled.

• All the dinosaurs, except for birds were gone by 65 million years ago.

Class Aves-Birds

• Birds evolved during the great reptilian radiation of the Mesozoic era.

• Birds have amniotic eggs and scales on their legs, two reptilian traits.

• Look quite different from modern reptiles because of their feathers and other distinctive flight equipment.

• Include only a few flightless species, which evolved from flying ancestors

• Birds include over 8,600 species.

• 4 chambered heart, endothermic, scales

Birds of a Feather Stick Together• Almost every element of bird anatomy is

modified in some way that enhances flight.The bones are honeycombed which makes them strong, but light.

• The absence of some internal structures found in other vertebrates further lightens birds.

• Females have one ovary instead of two. Birds are toothless, using a gizzard to grind food. Birds have powerful breast muscles anchored to a keellike breastbone.

• Feathers are made of keratin, and may have first served as insulation, and later as flight gear.

• Birds are endotherms using their own metabolic heat to maintain a steady body temperature.

• Flight may have evolved through a combination of gliding downward and jumping into the air from the ground.

UNIT 9 - PLANTS Pt. 1

Chapter 16:Plants Move Onto Land

Why should we study plants?

• Plants provide beauty to our world!

• In addition, plants are very important to us!

• For example, they give us food, clothing, energy supplies, lumber, paper, oxygen, water, recreation, art, and products such as rubber.

• However, some forests are being cut down and not replaced.

• And clear-cutting practices have become common, often exceeding the rate of reforestation.

• How can we help? Become educated! Offer solutions!

• This unit will focus on plant biology, and through your research and presentation, you can offer forest management solutions!

Plant Kingdom: multicellular,

eukaryotic, autotroph (by photosynthesis)

• Have land adaptations - are different from algae:

1.Mycorrhizae-root-fungus combinations - fungi absorb water and minerals from soil, plant sugar nourishes fungi

2.Stomata - microscopic pores through leaf’s surface, exchange CO2 and O2

3. Cuticle - waxy layer coating leaves and other aerial parts, helps retain water.

4. Lignin - chemical which hardens cell walls (skeleton)

5. Roots and shoots con’t)

6. Xylem tissue (transports water up) and Phloem tissue (transports food around)

7. Protected embryo: gametangia - a jacket of protective cells surrounding a moist chamber where gametes can develop w/o drying out (in female parent)

8. Seed dispersal - rely on wind or animals

The Origin of Plants from Green Algae:• Charophyceans are a group of multicellular green algae closest to

plants in evolution. (see above)

• Next came 4 major periods of plant evolution: bryophytes (mosses); ferns; gymnosperms (conifers); and angiosperms (flowering).

Highlights of Plant Evolution Chart:

Plant Kingdom: multicellular,

eukaryotic, autotroph (by photosynthesis)

• Have land adaptations - are different from algae:

1.Mycorrhizae-root-fungus combinations - fungi absorb water and minerals from soil, plant sugar nourishes fungi

2.Stomata - microscopic pores through leaf’s surface, exchange CO2 and O2

3. Cuticle - waxy layer coating leaves and other aerial parts, helps retain water.

4. Lignin - chemical which hardens cell walls (skeleton)

5. Roots and shoots con’t)

6. Xylem tissue (transports water up) and Phloem tissue (transports food around)

7. Protected embryo: gametangia - a jacket of protective cells surrounding a moist chamber where gametes can develop w/o drying out (in female parent)

8. Seed dispersal - rely on wind or animals

The Origin of Plants from Green Algae:• Charophyceans are a group of multicellular green algae closest to

plants in evolution. (see above)

• Next came 4 major periods of plant evolution: bryophytes (mosses); ferns; gymnosperms (conifers); and angiosperms (flowering).