ESPM 42 Exam 1 study guide

Focus is on whole organisms and their relationship and interactions.
Cuts across disciplines.
It is more pattern and observation driven than experimental
It is the story of the natural world that is at once scientific and question driven, descriptive, and historical.

Natural History

Minute, near relative of Arthropods.
Some survived exposure in outer space by curling into a dry, nearly lifeless ball (tun).
About 1000 spp.

Tardigrada

Near relatives of Arthropods.
About 100spp
Good fossil record in marine sediments.
Have slime glands that shoot “glue” used for prey capture or defense.

Onychophora

Bilaterally symmetrical
Segmented
Exoskeleton
Open circulatory system
Ventral Nerve Cord
Dorsal Artery

Phylum Arthropoda (6 characteristics)

Evolutionary relationship among biological entities (e.g., species)

Phylogenetic

insects, spiders, crabs, etc.

Arthropods

Time
Character evolution
Ancestry
Relationships
Taxonomic groups
They are predictive

Phylogenetic trees can represent

When cut in half, is symmetrical
Humans and Arthropods fall under this category

Bilaterally symmetrical

~550 million years ago.

Last common ancestor of humans and arthropods was

Trilobites (fossils only)
Chelicerata (spiders, mites, ticks, scorpions, etc.)
Myriapoda (millipedes, centipedes, etc.)
Crustacea (crabs, lobsters, shrimps, etc.)
Hexapod (insects and close relatives)

Some features of the common arthropod group

Trilobites (fossils only)
Chelicerata (spiders, mites, ticks, scorpions, etc.)
Myriapoda (millipedes, centipedes, etc.)
Crustacea (crabs, lobsters, shrimps, etc.)
Hexapod (insects and close relatives)

Some features of the common arthropod groups

Enables more community engagement
Increases the scope of data collection
Decreases time needed to analyze data
Public becomes more informed which can impact policy on a greater scale

Benefits of citizen science

Outside, Inside

Arthropods have their exoskeleton on the ___, Vertebrates have them on the ___

Underside, Top side

Arthropods have their nerve cord on the ___ of their body, Vertebrates have their nerve cord on their ___ of their body

Top side, Underside

Arthropods have their dorsal artery or “heart” and open circulatory system on their ____, Vertebrates have their dorsal artery or “heart" on their ___

Went extinct 240 mya
20,000 species recognized
Exclusively marine
Most were bottom-dwellers on the sea floor or in reefs.
Predators or scavengers
Trilobites have the typical arthropod body plan.
Trilobites flourished for 150-200 million years, then declined and went extinct in the extinction event that ended about 80% of all marine species at the end of the Paleozoic.

Trilobites (Fossil taxa)

No antennae
4 pairs of walking legs; total of 6 pairs of appendages - 1st air are the Chelicerae
No distinct head (Cephalothorax)
“Head” fused into the thorax

Chelicerata (spiders, mites, ticks, scorpions, etc.)

Pair of antennae
Many pairs of appendages on many body segments
Distinct head

Myriapoda (millipedes, centipedes)

2 pairs of Antennae
Many pairs of appendages on many body segments
In Isopods, the first antennae are typically chemosensory; the second antennae are typically tactile structures.
Remipedia + Cephalocarida are called the Xenocarida and are sister to Hexapoda.

“Crustacea” (crabs, lobsters, shrimp, isopods, water fleas, barnacles, etc.)

A Superclass
1 pair of antennae
3 major body regions
Head
Thorax
Abdomen
3 pairs of walking legs
Most have wings (Insecta)

Hexapoda (insects and near relatives)

Result of Tagmosis
Grouping segments into a functional unit

Tagmata

Sensory
Ingestion
Brain

Head

Maxillae
Labrum
Labium

Mouth parts for chewing

Locomotion
Legs

Thorax

Wings
3 Segments

Pro-, Meso-, and Metathorax
Meso- and Meta- bear wings

Three segments of thorax (including the segments that bear wings)

Houses organs for digestion
Reproduction
Excretion
Has 9-11 segments
No true walking appendages

Abdomen

Protection (Physical protection)
Nutrients
Respiration
Mating
Environmental control and selective permeability
Mobility and movement

What challenges do living organisms face that are dealt with or mediated by the exoskeleton of insects?(6 categories)

Multi-layered shell (no gaps)
Varies dynamically through development and in different regions of the body
While jointed and a protective layer like a suit of armor, an insect exoskeleton does NOT have gaps.
Nearly everything you see when you look at an insect is part of the exoskeleton.
The exoskeleton is a naturally-produced biocomposite

Key feature of Arthropods (Joint Exoskeleton)

Epicuticle
Wax

Cement Layer
Protects against moisture loss

Exocuticle
Relatively rigid
Microfibers of chitin surrounded by a matrix of protein
Scrierotization
Individual protein molecules are linked together by quinone compounds.

Endocuticle
More flexible
Microfibers of chitin surrounded by a matrix of protein

Polysaccharide is a major component of the exoskeleton of insects and other arthropods. It forms chains and a scaffold for the cuticle and is a tough, pliable material.

Chitin

When individual protein molecules are linked in the chitin matrix to make the exoskeleton hard.

Sclerotization

Efficient at small size
Tubular design is stronger than solid rod at weight
Flexible and light enough for flight
Provides good protection for soft internal structures

Good features of exoskeleton (4 qualities)

Growth must occur in discrete stages
Size limiting factors and the Surface Area to Volume problem
Mass increases faster than muscle strength
Limits to respiration rate
Size limiting factors
Overstress of exoskeleton would lead to buckling
Pin joints are under excessive stress

Drawbacks of exoskeleton (4 qualities)

Top side

Dorsal

Underside

Ventral

an invagination of the outside cuticle of the insect (ingestion)

Foregut

main digestive and absorptive portion of gut.

Midgut

storage

Hindgut

passage of digested food and excrement; some absorption, especially water.

Role of hemolymph is NOT gas exchange
Does transport nutrients, hormones, heat, defensive cells, etc.
No true blood vessels except for the muscular dorsal vessel

Open-body cavity, the hemocoel, organs and hemolymph

Blood worm (Chironomid fly)
Backswimmer
Bot fly

Hemoglobin

a key to insect success on land. Extracting oxygen from the air.

Tracheal system (full of air tubes)

Image of an insect spiracle with the muscle and other soft tissue removed. Only cuticles remains.

Taenidia

gills or direct diffusion

Aquatic insects

0.0025% Diving beetle
0.0057% Honey Bee
2% in humans

Brain facts (% of body size)

Every receptor is of multicellular origin
Seta or hair
Sensory neuron

Touch (Mechanoreceptors)

Insect “ears”, sound sensitive organs, can be found on many parts of the body in different insects.
Substrate vibration, nearby air

Hearing

water vibrations, and distant sounds.

Smell

Surface, air and liquid chemical detection

Taste

Stemmata
Larval eyes
Ocelli
Adult simple eyes
Pixelated sight

Vision

Ovaries
Spermatheca
Accessory glands

Internal organs (female)

Testes
Accessory glands

Internal organs (male)

Aquatic juveniles
The only living insect order with a sub-adult winged molt
2 pairs of wings, held straight above the body.
2 or 3 long, threadlike tail filaments
Reduced mouthparts

Ephemeroptera (mayflies)

Aquatic juveniles
Predacious
Males have two kinds of genitalia in different places on their bodies.
2 pairs of wings, held horizontal or straight above the body.
Very large eyes.

Odonata (Dragonflies and Damselflies)

2 pairs of wings, folded roof-like over the body. Or no wings.
Large, shield-like prothorax
White, “ant like” workers and flying reproductive forms.

Blattodea (Cockroaches and Termites)

Highly predatory and used modified raptorial front legs.
Some are extremely well camouflaged
Females exhibit “sexual cannibalism” only about 15% of the time.
Big eyes
Raptorial front legs

Mantodea (Mantids)

Chewing mouthparts (and smug look on their faces)
2 pairs of wings and the hind wing are membranous. Or no wings.
Often they have large, powerful hind legs for jumping.

Orthoptera (Grasshoppers, Crickets, and Katydids)

One of the big 5 orders with around 80,000 species
Many are plant feeding but some are predators and some feed on blood.
Aphid poo, called “honeydew” is eaten by some ants that tend them.
Piercing, sucking mouthparts.

Hemiptera (true bugs)

Biggest of the big 5 with >350,000 species
Occur in virtually every conceivable habitat.
Includes the most massive and nearly the tiniest of insects.
Tiny beetles that live in the pores of fungus.
Forewings modified into hard covers called elytra (singular elytron)

Coleoptera (Beetles)

Another of the big 5 with nearly 300,000 species
Most are night-flying moths, only about 17,000 are butterflies
The caterpillar is the most important stage for economic impact.
2 pairs of wings, folded roof-like over the body or straight above the body.
Wings and most of the body covered in scales (modified hairs)

Lepidoptera (moths and butterflies)

A big 5 order with about 150,000 species
Incredibly diverse and interesting life histories
Most medically important order for humans.
Only one pair of flight wings

Diptera (flies)

Last of the big 5 with 150,000 species described, and many more to be described.
Most important pollinators for human crops
Include the only group of insects with a true sting.
Two pairs of wings (or none)
Biting, chewing mouthparts.
Incredible array of forms, many modified parasitic life.

Hymenoptera (bees, ants, wasps)

The correct form and usage of formal organism names.

Taxonomy, Systematics, & Nomenclature

Nomenclature is the system of scientific names for taxa (such as species, genera, or families) and the rules and conventions for the formation, treatment, and use of those names.
It follows an internationally agreed, quasi-legal procedure.

Biological Nomenclature

Genus upper case → Specific epithet lower case → For first use add author & year where appropriate (if in doubt as editor)

Decoding a name

rules of Nomenclature (ICZN - ICBN)

Names are given to species and higher taxonomic groups using…?

provide a unique name for every species and higher category covered by the governing rules.

The purpose of naming species is to…

how we name, but not what we name (i.e., science is not regulated)

Rules cover…

Nomenclatural stability and clarity
Universality
Uniqueness

If science is not regulated, then what is regulated in the codes?

Priority - first published name is the correct one to use. (except when it is not)
Availability - a properly published name is “available”
Validity - the correct name to use.

How are names regulated?(name the three regulations and their definition)

Name bearing Type specimen.

Holotype

Acts as an objective basis for the linking of nomenclature to taxonomy
Voucher (or “supervoucher”) of research
A single datum that provides a fixed reference point for our character descriptions
Not necessarily average or typical in the sense of being the common form.
Can’t represent variation

Function and attributes of types (5 attributes)

Kingdom
Phylum
Class
Order
Family
Genus
Species

Formal System of Categories or Ranks

Creator of the Formal System of Categories or Ranks
Carolus Linnaeus

Intrinsic to organism
Underlying common process
Is real

Natural

May include information that is both intrinsic and extrinsic to organism
No common process
Human concept

Artificial

Classification System
Allow for storage, retrieval and communication of information.

Hierarchical system
Best reflects genealogical relationships among organisms
Consistent with descent with modification-Darwin’s theory of evolution.

Information Content
Summarizing what is known about organism

Predictivity
What is not yet known about organisms

Function in theories
Capturing entities involved in important natural processes.

Nomenclature
The system of scientific names for taxa (such as species, genera, or families) and the rules and conventions for the formation, treatment, and use of those names.

Taxonomy
A science using morphological, behavioral, genetic and biochemical observation to identify and describe biological diversity.

Systematics
The scientific study and interpretation of the natural system of relationship of groups of biological organisms.

Numbers of individuals
Biomass
Numbers of species

Some measures of biodiversity “success” (3 measures)

10 quintillion (10,000,000,000,000,000,000)

At any time it is estimated that there are some ___ individuals insects alive at any given time

Expert predictions and extrapolation
Local sampling extrapolated to global estimates
Prediction based on taxonomy

Methods used to estimate the number of species on Earth (3 methods)

Very poor sampling and study of other groups, e.g., fungi and nematodes.
Humans know more insects because they are easy to see (many don’t require a powerful microscope).
Insects are structurally complex and species are easier to recognize than more “cryptic” organisms.

Bias? Perhaps insects are not the most diverse form of life.(name three possibilities)

Physical Characteristics
Ecology

Ultimate factors for rich insect biodiversity (3 reasons)

Behavior
Climate

How many times has powered flight evolved (4 instances)?
Birds
Bats
Pterosaurs
Insects

Flight
The ability to disperse and find new niches and take advantages of resources
Metamorphosis
The ability to take advantage of different resources

Insects have the ability to colonize those niches (3 ways and their advantages)

habitat
More flexible development and modularity
Plant-insect coevolution
Defense and counter-defense
Chemical detoxification to overcome plants toxins
Mutualistic

Evidence is mixed, but there are few studies showing an impact.
Desiccation and temperature resistant
Endure extreme conditions or evolve rapidly.

Are insects impacts more or less than other animals and so diversify more in response to climate change?

Large, widespread populations are easily fragmented.
Rapid generation turnover.
Small size and heterogeneous habitat structure makes them more likely to be subject to reproductive barriers.
Complex genitalia makes them more likely to be subject to reproductive barriers.

Rate of speciation is inherently high for insects because…(4 reasons)