Lecture Exam 4

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Cambarian explosion

Cambarian explosion

535-525 MYA -All phyla formed -New predator-prey relationships -Adaptive Radiation & Diversification

Animals- Muscles, nerves, tissues, absorptive nutrition by ingestion

Cephalization

the concentration of nerve tissue and sensory organs at the anterior end of an organism

origin of mammals

about 200 million years ago

The last common ancestor of all animals was probably a

flagellated protist

metamorphosis

change of form during embryonic development

Clade Ecdysozoa

Phylum Nematoda Phylum Arthropoda

Clade Lophotrochozoa

share the presence of a trochophore larva or a feeding structure called a lophophore -Platyhelminthes, Rotifera, Mollusca, Annelida

Clade Eumetazoa

animals with true tissues

Clade Parazoa

Phylum Porifera -> Sponges

Clade Radiata

Phylum Cnidaria and Phylum Ctenophora -Radial Symmetry

Clade Bilateria

contains Lophotrochozoa, Ecdysozoa, and Deuterostomia -Bilaterally symmetrical

Clade Deuterostomia

echinoderms and chordates -Triploblastic

Deuterostomes

Animals in which the blastopore becomes the anus during early embryonic development

Protostome

an animal whose mouth is formed from the blastopore -Determinate And Spiral cleavage

protostomates

mouth forms from blastopore. Determinate Cleavage -Phylum Annelidia -Phylum Mollusca -Phylum Platyhelminthes -Phylum Arthropoda

Blastula

The hollow ball of cells marking the end stage of cleavage during early embryonic development

blastopore

The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes

Chordate Features

Dorsal, hollow nerve cord Notochord Pharyngeal slits Muscular Postanal tail Segmented Muscles

Deuterostomate, bilateral, triploblastic

Cleavage (embryology)

-series of rapid mitotic divisions in early embryonic development -increasing ratio of nuclear to cytoplasmic material -increases surface-to-volume ratio of each cell, improving gas and nutrient exchange

-Deutro vs proto

Gastrulation

In animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula.

-Can tell Triplo vs Diplo

Subphylum Cephalochordata

lancelets (amphioxus)-oldest chordates -Suspension feeders -Pharyngeal slits for water to go in/exit -cilia on outside -Diatoms and dinoflagellates inside

**Features in adults AND larvae

Ecdysis

periodic shedding of the cuticle in arthropods or the outer skin in reptiles

Subphylum Urochordata

tunicates -> Chordate features ONLY in larvae -Adults are IMMOBILE and lose chordate features (Derived traits -> ancestors=chordates) -Only have pharyngeal slits

Unikonta

amoebozoans and opisthokonts

Subphylum Vertebrata

Vertebrates; cephalized chordates a. A vertebral column b. Closed circulatory system c. Neural crest -> Infolded ectoderm d. Bones e. Brain f. Cranium (skull)

**2 sets of hox genes

Opisthokonta

the eukaryotic supergroup that contains the fungi, animals, and choanoflagellates

Subphylum Cyclostomata (Circle Mouth)

Class Mixini and Petromyzontida -Jawless -Simple Vertebrates

Clade Metazoa

all animals

Class Mixini

hagfish (Not fish) -Jawless Craniates -Marine scavengers -skull, simple vertebra -Cartilaginous-> NO COLLAGEN -Make slime for protection

Class Petromyzontida

Lampreys -Cartilaginous-> NO COLLAGEN -Jawless, vertebra-like extensions on notochord -Parasites; eat blood -> larvae suspension feed

Subphylum Gnathostomes (Jaw Mouth)

-JAWS -> Predators -Additional hox gene cluster -Mineralized endoskeleton -Lateral line system -> better senses and bigger brain -Tetrapods -> legs and arms

**Fish, amphibians, reptiles, mammals

Origin of Jaws

-Skeletal rods supporting pharyngeal slits fuse around the mouth -Other slits become GILLS for respiration -No more suspension feeding

Chondrichthyes (cartilaginous fish)

Sharks And Ray fish & ratfish -true jaws and Cartilage endoskeleton -paired fins -hypertonic to Ocean -Must be constantly swimming

Superclass Osteichthyes (bony fish)

-Endoskeleton made entirely of hard calcified bone -Operculum= protects gills and allows fish to draw in H2O and breathe -swim bladders= "Lungs" -> controls buoyancy -gills for respiration -Lateral line system -Oviparous

3 Classes: Class Actinopterygii Class Actinistia Class Dipnoi

Class Actinopterygii (ray-finned fishes)

-Origin Silurian Period 444-419 MYA -Aquatic -Fins supported by long flexible rays -> maneuvering, self defense

Class Actinistia (lobe-finned fish)

-Rod shaped bones surrounded by thick layer of muscle in pelvic and pectoral fins -3rd surviving group of lobe fins= survived on land -Silurian Period

Class Dipnoi (lungfish)

-Gills= main organs for gas exchange

Class Amphibia

Paleozoic- 365 MYA -Flattened head and arms come to sides -Presence of neck -Shell-less eggs -Frog= soft skin -Toad= rough skin

**Gave rise to reptiles and mammals

3 clades: Urodela- Salamanders Anura- Frogs (tail-less) Caecilians (Apoda)- (snakes Legless)

Missing Link Traits-Amphibians

Juveniles- Gills. Swim tail, Webbed feet, fish like Adults- Lungs, moist skin, H2O to reproduce

Reptile characteristics

Water proof scales Independent from water -DRY skin, keratinized cells -Lay Amniotic eggs on land -> Pre-fertilized= SHELLS COVER ZYGOTE -Egg Shell: Stores H2O, leathery, waste excretion (NH3-> Uric acid), gas exchange (Air pockets)

Reptile groups

Synapsids -Therapsids-> give rise to mammals -1 opening in temporal arch

Diapsids -Dinosaurs, crocodiles, snakes, lizards, birds -2 openings in temporal arch

Anapsid -Turtles -NO opening in temporal arch

Types of teeth in mammals

incisors= shredding canines= ripping and piercing molars= grinding

mammal characteristics

-Warm blooded -High metabolism -Sweat glands to cool -specialized teeth -hair -Mammary glands -Extended care of young -Learned behavior

Subclass Prototheria

monotremes (Porcupines) -Warm blooded -Lay eggs -> Young hatch and live outside mom -hair -NO NIPPLES -Milk glands

Subclass Metatheria (marsupials)

-Live Birth -Temporary placenta -Underdeveloped young -> stay in mom's pouch -Attached to nipple -> feed off nipple for milk

Subclass Eutheria (placental mammals)

-Live birth -Fully developed child after birth -Young held inside past egg feed development -Feed by umbilical cord attached to placenta -Long-term placenta -Feed off breast for milk-> NOT physically attached to nipple

**Convergent evolution with Marsupials -> look similar

Tetrapods

vertebrate animals having four feet, legs or leglike appendages -digits on feet and arms -Neck= sep movement of head -Fusion of pelvic girdle and backbone -Ears-> detect airborne sounds -Absence of gills

Origins of flight

Arose 4 times

1. Pterosaurs -> Flying reptiles

2. Bats

3. Birds

4. Insects

2 theories: Tree Down Theory Ground Up Theory

Bird (aves) characteristics

-feathers -> Flight -forelimbs have become wings -lay eggs with hard shells -4 chambers in heart -Warm blooded high metabolism -Lungs and air sacs= one way flow -Hollow bones -Parental care and social behavior -One ovary -NO TEETH OR URINARY BLADDER

Primates New Features

-Origins to 65 MYA -Insect eating nocturnal mammals -Derived Trait-> Life in trees -grasping hands and feet -Fully opposable separate big thumb -Fingerprints -Larger brain -Short jaws -Hand to eye coordination -Flat nails, no claws -Long parental care -Learned Behavior -Single births ANY time of yr

Primate Groups

prosimians -Lemurs and Tarsiers -> more related to OG primates

anthropoids -Monkeys and Hominoids -> Split from Prosimians 45 MYA

New World Monkeys

All species are arboreal -Nostrils open to the side -Many have prehensile tails. -Squirrel and Capuchin monkeys

Old World Monkeys

Split from New World Monkeys 35 MYA Include arboreal and terrestrial species -Lack prehensile tails -Nostrils open downward -Rhesus Monkeys, baboons, macaques

Hominoids

apes and humans Split from Monkeys 20-25 MYA -More flexible/learned behaviors -NO PREHENSILE TAILS -Larger brain to body ratio / larger size -Social Behavior

Orangutans and Gibbons -> Primarily Arboreal Gorillas, Chimps, Us -> Primarily Terrestrial

Hominins

-Humans and our direct ancestors since split from Chimps 6-8 MYA

Major Groups: Australopithecus Paranthropus Homos -> some co-existed

Hominin Evolution/Characteristics

Driven by Life on LAND -bipedalism -Smaller Jaw with SPECIALIZED teeth -> Omnivorous diet -Pronounced chin -Less Sexual Dimorphism -> no real harem/dominant male -Tool use -Language -Social behavior -Walking Upright -expanded brain -Decreased sense in smell nut increased vision and muscle coordination -Eyes are larger and directed forward -Mosaic Evolution-> Not all traits happened at same time

mosaic evolution

a phenotypic pattern that shows how different traits of an organism, responding to different selection pressures, may evolve at different rates

Chromosome anomaly

Other extant Hominids -> 2n=48 -2 Ape chromosomes fuse -> become humans with 2n=46

Paedogenesis

The early development of sexual maturity in an adolescent -> Larger cerebrum in hominins

Sahelanthropus tchadensis

The earliest pre-australopithecine species found in central Africa -OLDEST-> 6-7 MYA (discovered 2002)

-Reduced Canine teeth -Flatter Faces -More Upright & Bipedal other hominids

Orrorin tugenensis

-6.1 MYA-5.8 MYA (Discovered 2000) -Evergreen forest -> Not in open grassland -Oldest Bipedal Fossil Evidence

Ardipithecus ramidus

4.4 MYA -"Ardi"-> most complete skeleton found -wooded environment-> contradicts open Savannah theory for origins of bipedalism -small brain -walked upright -big toe separated from other toes

Australopithecus

the earliest humanlike creature 3-4 MYA -Fully upright walking -Human-like teeth and hands

• 1/3 of modern human skull size -Lasted over 1 MY in South and East Africa

Homo Naled

2.5-3 MYA (Not sure) (found 2012) -Base of Homo Genus -Fully Bipedal -Fine Hand/Motor skills

Homo Habilis

1.6-2.5 MYA -Walked upright for 2 MY -USED Brains -Fashioned STONE TOOLS -Co-existed with Australopithecus for 1 MY

Homo ergaster

1.6-1.9 MYA -Less sexual dimorphism and more monogamy -larger brains -Slender legs -> Long distance walking -> Migrations -Smaller teeth= Prepared/cooked food -Smaller fingers= no more climbing trees -More advanced tools and more habitats

Intermediate btwn Habilis and Erectus

Homo erectus

300,000 YA- 1.8 MYA First to Migrate OUT to Europe and Asia -Larger populations -More advanced hunting -> Oldest evidence of use of fire -Java Man and Pecking Man

Homo heidelbergensis

A transitional species between Homo erectus and Homo sapiens -Descended from H. ergaster in Africa and spread out

Europe in ICE AGE: 3 populations LOSE CONTACT and speciate:

Europe: Neanderthals Asia: Denisovans Africa: Homo Sapiens (us)

Homo neanderthalensis

40,000-200,000 YA -Buried dead -Hunting tools from stone and wood -Carnivorous -Larger brain size than us (Maybe)

**Interbred With H. sapiens -> 20% European genome is Neanderthal (Except Y chromosome 100% Sapien)

Denisovans

41,000 YA -Formed from H. heidelbergensis -More closely related to Neanderthals than us -Not much info -> only have small DNA fragments -Fossils in Spain -> May have interbred with Neanderthals

**Papua New Guinea ppl have Denisovan DNA -May have been around until 60,000-110,000 YA

Ethology

The scientific study of how animals behave, particularly in natural environments.

behavior

what and how animals do things

Reductionism

Single out/isolate variable you are testing

causes of behavior

Ultimate Causation: Ecological/Evolutionary reason -> How to maximize fitness

Proximate Causation: Trigger/signal causes behavior

Innate Behavior

Genetically determined behavior -> Instinct

fixed action pattern

A sequence of unlearned acts that is essentially unchangeable and, once initiated, usually carried to completion.

-Perform behaviors without having seen them performed -> Don't think abt it, instinctive -Triggered by sign/stimulus

learned behavior

a behavior that has been learned/modified from experience or observation

Learning

The modification of behavior based on specific experiences.

Maturation

biological growth processes that enable orderly changes in behavior, relatively uninfluenced by experience -Period of learning

Habituation

A loss of responsiveness to stimuli that convey little or no information. -Temporary-> can be reversed

Imprinting

the process by which certain animals form attachments during a critical period very early in life -PERMANENT

classical conditioning

a type of learning in which one learns to link two or more stimuli and anticipate events -Link background stimulus with reward or harm

operant conditioning

Learning based on the consequences of responding -Trial and Error learning -Can either reinforce or diminish behavior based on reward or harm