Warm-Up

Classify each of the following organisms according to the phylum in which they

belong:butterfly, snail, earthworm, jellyfish,

sponge, starfish, lobster

Early Animals…The Cambrian Period

• 1st multicellular animal thought to have arisen ~540 million years ago

– Flat, plate-shaped, lived on sea floor

Phylum Chordata:

• Must have (at some stage of life):– Dorsal (back) region– Hollow nerve cord– Notochord – supporting rod of tissue during

embryo stage– Pharyngeal pouches – paired structure in

throat– Tail extending beyond anus

(often in seen in embryonic stage)

Subphylum Vertebrata

• Backbone composed of vertebrae that enclose and protect spinal chord

• Nonvertebrate chordates – Ex. Tunicates (sea squirts) and lancelets

Lancelet (first notochord)

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Fish (Ichthyes)Characteristics:• Aquatic• Obtain oxygen from water via gills • 2-chambered heart• Exothermic: cold-blooded• Jaws have evolved over time

Cartilaginous FishesChondricthyes

• Endoskeleton is made of cartilage

• Body covered with triangular scales.

• Ventral mouth with several rows of triangular teeth that replace themselves.

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SkatesSkates

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Bony Fish (Osteichthyes)• First skeleton made entirely of bone

• Paired fins made of rays and spines, or lobed fins lacking the rays and spines.

Fish Reproduction

• Both internal AND external development• Some types of fish reproduction:

– Oviparous – eggs hatch outside of mother; ex. (salmon)

– Ovoviviparous – eggs stay inside mother but are born alive; ex. (guppies)

– Viviparous – embryos stay in mother and are born alive; ex. (sharks)

Amphibians – “double life”

Characteristics:• Bony skeleton, usually have 4 legs• Respiration:

– Tadpoles gills– Adults breathe through moist skin; lungs

• First 3-chambered heart• Exothermic

– cold-blooded

Amphibians – “double life”

Characteristics: • Lay aquatic eggs (external development)• Larvae are fish-like (tadpoles)• Adults are terrestrial• Many frogs do external fertilization; females lay

eggs in water and male frog sprays sperm on them!

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CaeciliansCaecilians

SalamandersSalamanders

FrogsFrogs

Evolutionary advantages of adapting to life on land

• Water availability

• Air temperature / oxygen

• Physical support

• Keener sensory input

• Escape aquatic predators

Reptiles

• Characteristics:– 3-chambered heart; more efficient lungs– Exothermic: cold-blooded– Greater integration of sensory input and motor Greater integration of sensory input and motor

responseresponse

Reptiles

• Characteristics:– Dry, scaly skin– Lay terrestrial eggs (external development)

How did reptiles escape from water dependency?

• A scaly skin that is resistant to drying

• Internal fertilization

• Kidneys are good at conserving water

• Amniotic eggs with membranesand a shell

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Birds (Aves)

• 2 scaly legs • Front limbs are wings• Endothermic – warm-blooded

– Some birds have body temps of 41 degrees Celsius (105.8 degrees Fahrenheit).

• Internal fertilization, external development– Offspring hatch from eggs, parents provide some care

Bird Advantages/Adaptations

• Four chambered heart allowed birds to be endothermic so they could live in colder climates

• Hollow bones and feathers allow for flight (and insulation)

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Mammals

Characteristics:•Last appearing major class of animals•Mammary glands

– produce milk to nourish young

•Endothermic: warm-blooded•4 chambered heart•Hair•Cerebrum (brain) has cerebral cortex – coordination, thinking, and complex behaviors

Types of Mammals: Monotremes

• Monotremes lay eggs, and after birth they suckle/nourish their young

• Examples: duck-billed platypus, spiny anteater

Platypus

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Echidna

Types of Mammals: Marsupials

• Marsupials give birth to live young • The young then crawl to an external pouch on

the mother where they are nurtured and nourished until they complete development– This is similar to late embryonic development in

placental mammals

• Examples: kangaroos, koalas, opossums, wombats

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Whew! I can’t wait for the “empty nest” phase!

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Types of Mammals: Placental

• Placenta – tissue that joins the embryo and mother – Nourishes growing embryo inside uterus– Provides nutrients, oxygen, waste exchange, etc.

• Examples of placental mammals:– humans, mice, dolphins, etc.

Human Placenta

Umbilical cord

Inside of placenta

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Animal Behaviors• Innate behaviors – instinct, inborn

Behaviors that don’t have to be taught or learned…– Ex. Spiders building a first web.– Ex. Birds migrating (What is a benefit of migration???)– Ex. Your reflexes– Taxis: moving towards or away from a stimulus– Kinesis: random movement in response to a stimulus

Innate Behaviors

Animal Behaviors

Habituation: ignoring of stimuli that neither harms nor rewards

Animal Behaviors

•Learned behavior – developed over time– Classical Conditioning – mental connection to

stimulus

Animal Behaviors

•Learned behavior – developed over time– Operant Conditioning – learning to behave a

certain way (with rewards/punishments)• Trial and Error – learning with mistakes (mouse in maze)

Animal Behaviors

Animal Behaviors• Learned behavior –

developed over time– Insight Learning: reasoning,

prior knowledge applied to new situations

Animal Behaviors

•Learned behavior – developed over time– Insight Learning – reasoning, prior knowledge

applied to new situations

Animal Behaviors• Estivation

– Inactivity in orderto avoid hot temperatures in summer

• Ex. Cane toads

• Hibernation– Inactivity in order

to avoid low temperatures inwinter

• Ex. Bears

Animal Behaviors continued

• Imprinting – attaches to first moving object and assumes object will be caretaker

Animal Behaviors continued• Social behaviors

– Courtship– Competition– Aggression (agonistic behavior – a display to

look bigger, stronger and more threatening)

Animal Behaviors

• Jane Goodall – observed chimps in natural habitat, revolutionized field of animal behavior.