Chapter 31
The Vanishing Bees
Honeybees evolved…
 130 mil. years ago
 during the Cretaceous period
 one-third of bees die every winter – colony collapse disorder (CCD)
 bee stressors – diminish the health of a colony
o disease
o pesticides
o loss of biodiversity
o climate change
 the cost of bee pollination services has increased by 20%
 if bees disappear from the planet, many fruits/vegetables would become more
expensive or rare
Evolutionary Trends Among Animals
Animals placed in Animalia w/ domain Eukarya – traditional five-kingdom classification
Animals placed in Opisthokonta w/ domain Eukarya – three-domain system
What characteristics distinguish animals from other eukaryotes + how
these traits evolved?
Unlike plants, animals are heterotrophs + must acquire nutrients from an external source
Unlike fungi, animals ingest whole food and digest it internally
Animal characteristics…
 locomotion by means of muscle fibers
 multicellular; specialized tissues that form tissues and organs
 have a life cycle in which the adult is typically diploid
 undergo sexual reproduction, produce an embryo that goes through developmental
stages
 Heterotrophic; usually acquire food by ingestion, followed by digestion
SIMPLE INVERTEBRATES
Sponges
Comb jellies
Cnidarians
PROTOSTOMIA (platyzoa)
Flatworms
Rotifers
PROTOSTOMIA (lophotrochozoan) – (filter feeders with a mouth surrounded by a ciliated
tentacle like structure)
Lophophorate
Mollusks
Annelids
PROSTOMIA (Ecdysozoa)
Roundworms
Arthropods
DEUTEROSTOMES
Echinoderms
Chordates
VERTEBRATES
Fishes
Amphibians
Reptiles
Birds
Mammals
Evolution of the Animal Body Plan
Two body plans: invertebrates and vertebrates
Invertebrates
Lack an internal skeleton, or endoskeleton, of
one bones of cartilage; (the invertebrates
evolved first and outnumber vertebrates)
Types of Symmetry
Asymmetrical
Have no particular symmetry,
such as some species of
sponges.
Vertebrates
Animals with an endoskeleton
Radical symmetry
The animal is organized
circularly, (like wheels), so
that no matter how the
animal is sliced longitudinally,
mirror images are obtained.
Bilateral Symmetry
The animal has definite right
and left halves; only a
longitudinal cut down the
center of the animal will
produce a mirror image.
The Simplest Invertebrates
(phylum) Porifera – the only animals to lack true tissues and to have only a cellular level of
organization
 Only have a few cell types
 Lack the nerve and muscle cells seen in more complex animals
Sponges, molecular data show they are at the base of the evolutionary tree of animals
 Outer layer, flattened epidermal cells
 Middle layer, a semifluid matrix with wandering amoeboid cells
 Inner layer, Collar cells: flagellated cells or choanocytes
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Sessile filter feeder = an organism that filters its food from water by means of a straining
device
The pores of the walls and microvilli making up the collar of collar cells.
(phylum) Ctenophora
Comb Jellies
 Bodies made up of mesoglea: transparent jellylike substance
 Propel themselves by beating their cilia
Some Ctenophores are bioluminescent, enabling them to produce their own light
The Spiralia are a diverse group of protostomes.
Lophotrochozoa
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At some point are bilaterally symmetrical
As embryos, have three germ layers
As adults, have an organ level of organization
Are protosomes
o Include lophophorans (bryozoans, phoronids, and branchiopods)
o Trochazoans (molluscs and annelids)
o Lophophore, a mouth surrounded by a ciliated tentacle-like structure
Bryozoans
 Phylum Bryozoa
 Aquatic, colonial lophophorans
 (Individuals) zooids  colony, colonies cooperate as a single organism
 Zooids coordinate functions within a colony by communicating through chemical signals
 Filter food from water through lophophore
 Have exoskeletons, which can be used to attach to substrates
Brachiopods
 Phylum Brachiopoda
 Two hinged shells, top and bottom shell.
 Affix themselves to hard surfaces via muscular pedicel
 Use lophophore to feed
Phoronids
 Phylum Phoronida
 Live inside long tube of chitinous secretions
 Tube buried in ground their lophophore extends from it
 Only 15 species of phoronids exist worldwide
Molluscs
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Phylum Mollusca
Second most numerous group of animals
True coelom – body cavity of animals
All molluscs have three distinct body parts…
 Visceral mass
o Contains internal organs: digestive tract, paired kidneys, reproductive organs
 Foot
o Used for locomotion
 Mantle
o A membranous or muscular covering, does not completely enclose the visceral
mass
o Mantle cavity is the space between the two folds of the mantle
o Secretes a shell – exoskeleton
 Tongue like radula, an organ that bears rows of teeth used to obtain food’
Cephalopods
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foot evolved into a funnel about the head
powerful beak
radula (toothy tongue)
o e.gs: nautilus, squids, octopus
eyes – lens and retina w/ photoreceptors
o camera-type eye
brain is formed by fusion of ganglia
contraction of the mantle – how animals move quickly
o jet projection of water
Squids have remnant of shell under skin
Bivalves
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Shells have two parts
Shell separated by mantle
Adductor muscles hold the valves of shell together
Gills have down on either side of visceral mass
Visceral mass lies above the foot
o E.g. Clams - Anodanta, mussels, oysters, scallops
The heart of a clam
 Heart lies below the hump of the shell
o Within pericardial cavity
 Heart pumps blood into dorsal aorta  leads to various organs of the body
 Blood flows through spaces rather than through vessels
 Open circulatory system – blood is not entirely contained within blood vessels
o Happens in slow moving or sessile animals
Nervous system of a clam
 3 pairs of ganglia (anterior, foot, and posterior)
o All connected by nerves
 Clams lack cephalization (the concentration of nervous structures and functions at one
end of the body, in particular the head)
 “hatchet” foot projects from shell to move
Annelids
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Annelids are segmented, as evidenced by the rings encircling the outside of their bodies
Worms do not have internal/external skeleton
Most have a hydrostatic skeleton – a fluid-filled interior that supports muscle
contraction and enhances flexibility
Majority of annelids are marine
Vary in size from microscopic to earthworm
Closed circulatory system – blood vessels that run the length of the body and branch to
every segment
Excretory system consists of nephridia in most segments
Nephridium – a tubule that collects waste material, excretes it through an opening in
the body wall.
Polychates
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Marine annelids are the Polychaeta – the presence of many setae
Setae – bristles that anchor the worm or help it move
o in bundles on paradia, paddlelike appendages
Clam worms – Nereis, feed on crustaceans and other small animals
Chapter 32: Animals: Chordates and Vertebrates
To be classified as a chordate, animal must have…(characteristics)
 Dorsal supporting chord, notochord:
o Vertebrates' embryonic notochord (turns into) vertebral chord during
development
 Dorsal tubular nerve chord: canal filled with fluid
o Vertebrates, nerve chord is protected by the vertebrae.
o Called the spinal cord
 Pharyngeal pouches, only during development
o Turns into breathing apparatus
 Postanal tail extends beyond the anus
The vertebrates include
 Fishes
 Amphibians
 Reptiles
 birds
 mammals
Characteristics of the vertebrate body
 skull surrounding the brain
 two pairs of appendages
 cephalization
 segmentation
Nonvertebrate chordates
Nonvertebrate chordates are characterized by: notochord never becomes a vertebral column
Lancelets: marine chordates only a few centimeters long
Gene: Branchiostoma
 the only chordates that retain all 5 key characteristics of chordates as adults
o a notochord,
o a dorsal hollow nerve cord,
o pharyngeal slits,
o an endostyle,
o a post-anal tail
Tunicates: live on the ocean floor
 incurrent and excurrent siphons
What phylum is amphioxus? Chordata
 No brain but a small swelling at anterior end of nerve chord
3 regions of human brain?
 Forebrain,
 midbrain,
 hindbrain
Vertebrates: Fish and Amphibians
Vertebral column provides evidence that vertebrates are segmented
Closed circulatory systems: blood is contained entirely with blood vessels
Fishes: Evolution of the Jaw
First fish vertebrates were jawless
 jawless fishes
o hagfishes
o lampreys
 cartilaginous fishes – (have jaws)
o sharks, rays, skates, chimaeras
 have skeleton instead of bone
 5-7 gills on both sides of pharynx
 Lack gill cover of bony fishes
 bony fishes (have jaws)
o most numerous of vertebrates
o RAY-FINNED FISHES
 cod, trout, salmon, haddock
 paired fins
 supported by bony rays
 various lifestyles
 filter feeders
 opportunists
 predaceous carnivores
o swim bladder, regulates buoyancy
o LOBE-FINNED FISHES
 Ancestors of amphibians
 Adjusted flesh for land locomotion
 Lung used for respiration
Amphibians: Transition to Land
Live on both land and water.
Lifestyle:
 Larvae stage: in water
 Adult stage: on land
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Caecilians are classified as amphibians
o Fossorial
o Wormlike
o Live underground
Vertebrates: Reptiles and Animals
Reptiles: Amniotic Egg
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Hard, keratinized scales
Adaptation:
o Snakes use their tongue as sensory organ
 Lungs enclosed by ribs
o Rib cage expand partial vacuum: negative pressure  Air rushes to lungs
 Atrium divided into left and right chambers
o Division of ventricle varies
 Amniotic egg
o Develop on land, larvae in water stage unnecessary
o Egg provides…
 embryo with oxygen, food, water
 removes nitrogenous wastes
 protects embryo from drying out
 protection from mechanical injury
 due to the presence of chorion
Embryo has to develop in water
Placental mammals
The largest group of animals
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hair
mammary glands
nipples – nourishment for offspring
not monogamous (unlike birds)
humans are order primatada
humans are closely related to chimpanzees
bonobo vs chimpanzees?
 Bonobos are smaller
o Not as heavy
 Bonobos more likely two be bipedal – to walk on two legs
 Bonobo faces are black with pink pigmentation
o Chimps faces are lighter/pinker
 Bonobos have more shrill/scream more than chimps
Chapter 33: Behavioral Ecology
Benefits of living in a society
 African female lions live in a group, 2-18 closely related females
o Increase chances survival
 Genetically related
 Male lions leave after 2-4 years
 male lions kill unrelated cubs to start estrus
o Also create mating opportunity for other lions
Behavior: represents the way an organism reacts to a stimulus or situation
Movement or changes in thought patterns
 Controlled by nervous and endocrine systems
Nature vs nature question = to what degree our genes (nature) and environmental influences
(nurture) affect our behavior
Behavioral genetics and twin studies
Behavioral genetics uses studies to examine similarities and differences between monozygotic
twins, dizygotic twins, twins raised apart to attempt to address the nature or nurture debate.
DNA methylation  methyl group attaches to the cytosine base of DNA
Epigenetics
 Heritable changes in gene expression without changing the DNA sequences
 activating or inactivating genes without altering the DNA sequence.
Nurturing Behavior in Mice
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Maternal behavior in mice was dependent on presence of a gene called fosB.
Mothers inspect their young  info from receptors travels to hypothalamus.
o fosB alleles activated
o protein is produced
 protein begins a process during which cellular enzymes and genes
activated
end result: change in the neutral circuitry within the hypothalamus
o manifests itself in maternal nurturing behavior in young
females w/ fosB alleles tended to retrieve young after separation
Mice that do not engage in nurturing behavior
o Found to lack fosB alleles
o Hyptothalamus failed to make any of the products
o or activate any of the enzymes and genes that lead to maternal nurturing
behavior
Food Choice in Garter Snakes
Garter snakes, Thammophis elegans
 aquatic snakes like frogs and fish
 inland snakes like slugs
 Crossbreeds of aquatic garter snakes + land garter snakes suggest a genetic basis for
food choice
 Physiological difference?
 Tongue flicks at preferred prey
 Coastal snakes, higher number of tongue flicks than inland snakes to
smell of slugs.
 Inland snakes do not eat slugs because they are not sensitive to their
smell
o Two have different nervous systems
o Hybrids are intermediate
Egg-Laying Behavior of Marine Snails
Nervous + endocrine system responsible for the coordination of body systems.
Environment influences behavior
Fixed action patterns (FAPSs): a particular trigger in the environment
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FAPs could affect learning
Learning: durable change in behavior brought about by experience
Learning formed by experiences
o Habituation (form of learning) : animal no longer responds to a particular
stimulus due to experience
 E.g.: deer grazing along highway, ignoring traffic
Learning in Birds
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Laughing gull chick’s begging behavior in response to parent’s red bill appears to be FAP
o Pecking motion toward parent’s bill, grasps it
o Parents signal begging behavior by swinging their bill side to side
 Regurgitates food on floor
Experiment
Imprinting
Imprinting: simple form of learning, although it has strong genetic component as well
 First observed in birds
 Chicks, ducklings, and goslings followed the first moving object they saw after hatching
o Any object they see after a sensitive period of 2 or 3 days after hatching
o Sensitive period: behavior developed only during this time
Why do turkeys vocalize?
 to reassemble a flock after it has become scattered
Associative Learning
Associative learning: a change in behavior that involves an association between two events
 Birds that get sick after eating monarch butterflies don’t eat it anymore
 Smell of fresh bread may entice you even tough you just ate
(a) Classical conditioning: presentation of two different types of stimuli at the same time causes
an animal to form an association between them.
E.g. Russian psychologist Ivan Pavlov
 Dogs presented with food salivate
 Rang bell whenever dogs were fed
 Dogs salivate whenever bell rang regardless of food was presented
(b) Operant Conditioning: a stimulus-response connection is strengthened
e.g. give an animal a treat when the do a trick right.
B.F. Skinner’s test
 Caged rat happens to press a lever, is regarded with sugar pellets
 Rat regularly presses lever whenever hungry
Animal Communication
Social behavior among animals requires that they communicate with one another.
Communication: a signal by a sender that influences the behavior of a receiver
 e.g. bats send out sound pluses and listen for echoes to find food and caves
o moths understand the sound pulses as danger to avoid bats
Chemical Communication
Pheromone: chemical signals in low concentration that are generally passed between members
of the same species
 e.g. female moths secrete chemicals which are detected by receptors on male antennae
 cheetahs mark their territories by depositing urine, feces, anal gland secretions at
boundaries
Auditory Communication
 faster than chemical communication
 effective both night and day
 can be modified by loudness, pattern, duration, repetion
male birds have songs for…
 distress
 courting
 marking territories
Humpbacks have songs for..
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sexual purposes
o advertise availability of singer
Visual Communication: allows animals to signal others of their intentions without the need to
provide any auditory or chemical messages
 used by species that are active during the day
 e.g. honeybees waggle dance to indicate the direction of food.
Tactile Communication: occurs when one animal touches another
Behavior and Fitness
Behavior ecology: that most behavior is subject to natural selection
Territory and Fitness
Home range: where they can be found during the course for the day
Defend portion of their home range
 as a food source
 mating area
 this portion of home range is called their territoriality
o territoriality is more likely to occur during times of reproduction
 Ensure a source of food
 Exclusive rights to one or more females
 Place to rear young
 Protection form predators
Foraging for food
Foraging: searching for food
Optimal foraging model:
 it is adaptive for foraging behavior
 food choice to be as energetically efficient as possible
Reproductive Strategies and Fitness
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Primates are polygamous
Males monopolize multiple females
Females invest more time in offspring than males
o Adaptive for females to be concerned with good food source
 Food sources clumped  females congregate in small groups
 Few females are receptive at one time
o Males defend few females from other males
Polyandrous primates: Female mates with multiple males is
 Tamrins – squirrel sized new world monkeys
 Live in central or South America
 Live together in groups of one+ families
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Females mate with more than one males
Gibbons are monogamous: they pair bond
 Monogamy is rare in primates
 Monogamy happens when males have...
o limited mating opportunities
o territoriality exists
o male is certain the offspring are his
Sexual Selection
Sexual selection: a form of natural selection that favors features that increase an animal’s
chances of mating.
 Results in female choice and male competition
 Females produce a limited number of eggs,
o provide majority of parental care
o choosy about their mate
 they pass on physical characteristics, their fitness has increased
o if they choose a male, they will pass on characteristics to make him wanted by
other females
Human Males Compete
Humans are dimorphic
 males larger more aggressive than females
o result of sexual selection
 energetic costs of male-male competition
 increased stress associated with finding mates
o human men tend to live, 4-7 years less than females
Men Also Have a Choice
 men prefer youthfulness and attractiveness in females
o signs that their partner can provide them with children
 men choose women 2.5 years younger
 as they age, they prefer many years younger
 men, more capable of reproduction for many years than women
 by choosing younger women, older men increase their fitness
Societies and Fitness
Group living does have its benefits
 helps animal avoid predators
 rear offspring
 find food
 group more likely to approach predator than a solitary one
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larger number of individuals looking for food increases the chances of finding it
Sociobiology and Human Culture
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language and use of tools are essential to human culture
language…
o socialize children
o teach them how to use tools
o educate them
o train them in skills to increase their chances of success
cultural evolution has surpassed biological evolution
Altruism Versus Self-Interest
Altruism: self-sacrificing behavior for the good of another member of society
 altruism may compromise the fitness of the altruist
o while benefitting the fitness of the recipient
Kin selection: sacrificing for others with similar genes
Inclusive fitness: individual’s personal reproductive success as well as relatives
Chapter 37: Conservation Biology
The giant panda population
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risen 17% in the last decade
o status: endangered species  vulnerable
native to temperate broadleaf, mixed forest of southwest China
they disperse bamboo seeds
their habitat is in geographic/economic heart of China
o habitat loss due to economic development
o + poaching
Chinese govt est. 50 protected panda reserves
o Covers 3.8 million acres
 Home to 61% of panda population
They are national treasure for China
logo for the World Wildlife Fund.
Conservation biology and biodiversity
Conservation biology: interdisciplinary science with the explicit goal of protecting biodiversity
and Earth’s natural resources
(ethical principles for conservation biology)
Biodiversity: the variety of life on Earth; number of species found in a given area or ecosystem
 generated by evolutionary change has intrinsic value
 regardless of any practical benefit
Complex interactions within ecosystems and communities…
 Support biodiversity
 Maintenance of such interaction is therefore desirable
About 2.3 million species have been described in the world
Three levels of biodiversity…
1. Genetic diversity: number of different alleles + relative frequencies of those alleles in
populations and species
Do wild or captive cheetahs show more genetic diversity?
a. 12000 years ago cheetahs survived a population collapse – population bottleneck
b. Captive cheetahs show more genetic diversity
2. Ecosystem diversity: dependent on the interactions between species and their abiotic
environment in a particular area
a. Abiotic environment – consisting of living and non-living components.
3. Landscape diversity: involves a group of interacting ecosystems within a single
landscape
o Plains, mountains, and rivers may be fragmented to the point that they are
connected only by patches
 Allow organisms to move from one ecosystem to another
 Fragmentation of landscape
a. Reduce reproductive capacity
i. increase predation risk during dispersal between
habitat patches
ii. Difficulty in finding mates
4. Species diversity: number of species in a given area
Do wild or captive cheetahs show more genetic diversity?
 12000 years ago cheetahs survived a population collapse – population bottleneck
 Captive cheetahs show more genetic diversity
Human induced extinctions are undesirable.
Nearly 30,000 species worldwide are in danger of extinction
Endangered species: one that faces immediate extinction throughout all or most of its range
Threatened species: likely to become endangered in the foreseeable future
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Reintroduction of wolves into Yellowstone National Park save several species
Without wolves, elk numbers increase
More wolves  less elk more plants, trees more songbirds, beavers
Are black-footed ferrets found in Colorado?
 Yes!
o There are six release sights where those that were bred in captivity were bred
 One of the most endangered species in North America
 They were thought to be extinct…
 (until) a population was found in Wyoming
Direct Value
Direct value: individual species perform services for humans and contribute to the value we
should place on biodiversity
Medicinal Value
 Most prescription drugs in US derived from living organisms
o E.g. rosy periwinkle from Madagascar, tropical plant that produces useful
medicine
 Now used to treat leukemia and Hodgkin’s disease
o Antibiotic penicillin derived from a fungus
 Certain species of bacteria produce the antibiotics tetracycline and
streptomycin
 These are necessary in the treatment of STDs
o Bacteria of leprosy grow naturally in the nine-banded armadillo
 No cure for leprosy
 Source of the bacteria
o Blood of horseshoe crabs contain substance called limulus amoebocyte lysate
 limulus amoebocyte lysate – used to ensure that medical devices are free
of bacteria
 their blood is blue because it contains copper
Agricultural Value
Wheat, corn, and rice are derived from wild plants
Honeybees, and flies pollinate plants
Plants are genetically modified to produce higher-value
 rice crops in Africa were dying
o researchers grew rice until they found one that contained a gene for resistance to
the virus.
 Biological pest control: natural predators and parasites – more preferred than chemical
peticides
o Saves money
Indirect Value
Waste disposal : break down dead organic matter and other types of wastes into inorganic
nutrients that are used by producers within ecosystem
Consumptive Use Value
 Most freshwater marine harvests depend on wild fish and crustaceans
Threats to Biodiversity
5 causes for species extinction are identified
1. Habitat loss
2. Exotic (non-native) species
a. Exotic species kill out the native species by feeding on them
b. Bring new diseases
3. Pollution
a. Any environmental change that adversely affects the lives and health of living
things.
b. Also weakens organisms
4. Overexploitation
a. When the number of individuals taken from a wild population is so large that
the population becomes severely reduced in numbers.
5. Disease
a. Wildlife exposed to new pathogens from domestic animals
i. who move into areas with their encroaching humans
b. Canine distemper was passed from domesticated dogs to African lions,
i. causing population declines
c. Almost half of sea otter deaths along the coast of California are due to
infectious diseases
d. Infections of a fungal pathogen (chytrid fungus)
i. may be causing global population declines
ii. extinctions of amphibians
Bald eagle on endangered species in 1967
 DDT ban helped the eagle population recover
 It is used to control malaria
California condors were captured into captivity to recover the bird population