TAMU ENTO 201 Bernal Exam 1

How long ago did life begin?

3.5 Billion years ago

Define: Phylum

A taxanomic group of organism types

Define: Species

The fundamental unit of systematics and taxonomy

What percent of all described species are insects?

~ 50%

Define: Colonial Theory Hypothesis

During unicellular division, cells failed to separate. Over time this evolved into multicellular organisms.

What are suspected to have been the first invertebrates on land?

Crustaceans

Define: Phytophage

Plant eater

Are plants or athropods dominant in terms of biomass?

Plants @ ~78%

Define: Trophic Level

Levels of food/energy transfer in a foodchain

Define: Entomophilous Plants

Insect loving plants - these plants depend on insects for pollination

Wasp like organisms are classified under ___________.

Hymenoptera

Fly like organisms are classified under ___________.

Diptera

Intangible effects of insects on humans

Tend to be indirect and positive

Tangible effects of insects on humans

Tend to affect us directly and are generally negative

Insects account for what percent of lost food for Americans?

15-20%

What percent of insects are pests?

0.125%

Parasitoids generally favor which gender?

Female

Approximately how old is Earth?

4600 Million years old

How long ago are algae estimated to have first emerged?

3500 million years ago

During which time period did life explode?

The Cambrian era

What characteristics are used to classify organisms?

Morphology, behavior, molecular, and ontogenetic evidence

What's the difference between homologies and homoplasies?

Homologies: Similar traits from common ancestor

Homoplasies: Similar traits from convergent evolution

Basic characteristics of arthropods.

- Chitinous cuticle

- Segmented, paired legs

- Body segments grouped into tagmata

Define: Neopteran

Arthropods who's wings are held close to the body. Evolved second.

Define: Paleopteran

Arthropods who's wings are held away from the body. Evolved first.

Neopterans account for what percent of winged insect species?

99%

Define: Ametaboly

Having no metamorphic stages; occurs in non winged insects

Define: Holometaboly

Having complete metamorphosis

Define: Hemimetaboly

Metamorphic stages occur, however the insect looks generally the same throughout; wings are formed

Define: Paurometaboly

Similar to Hemimetaboly, however the insect undergoes slightly more morphological changes.

Five factors that contributed to insect success

- Small size

- Cuticle

- Efficient nervous system

- Flight

- High reproductive rate

Why is their size helpful to insect success?

- Gravity is different

- Volume:Surface area ratio favors volume

- More niches

- Strength:Size ratio favors strength when small

What is the respiratory limitation on insect wrt size?

Insects respire via spiracles which are only effective at small sizes

Insects are (endo or ectotherms)?

Ectotherms: They rely on ambient temperatures to determine body temp

Define: Apolysis

Process by which the old cuticle separates from the underlying epidermal cells

Define: Ecdysis

Process by which the old cuticle is shed following apolysis

What are the three layers of the cuticle?

Epicuticle, exocuticle, and endocuticle

Sclerotization indicates regions of _____________.

Inreased hardness

Reslin functions to ________.

Provide elasticity

An insect will increase haemolymph pressure or swallow air to undergo ____________.

Ecdysis

Insect brain is located _________ and the CNS is located _________.

Dorsally; ventrally

Define: Perineurium

Layer of glial cells beneath the lamella which is responsible for regulating the flow of ions between the CNS and haemolymph

Define: Neural lamella

Layer of connective tissue encasing the CNS and perineurium

What type of transport moves ions across the blood brain barrier?

Active

Define: Apterous

Wingless

Define: Paranotal Theory

Wings evolved from outgrowths of the thorax which had originally been used in gliding/thermoregulation

What is the biggest rock in the paranotal theory?

Modern wings have hinges, muscles, and vasculature that the notum outgrowths didn't possess.

Define: Endite-exite theory

The fusion of inner and outer appendages eventually gave way to wings

What are two major supports for the endite-exite theory?

- Wings are muscularized, vascularized, and hinged

- Wings possess chemo and mechno receptors that are also found on legs

Define: Campaniform sensilla

Mechanoreceptors on wings

Define: myogenic

Indirect muscle movements used during flight; muscle is used only on downstroke while spring forces generated from exoskeleton produce drive for upstroke

Define: Mycetocytes

Cells (often found in lipid tissues) that permanently house specific bacteria

Define: Secondary winglessness

Having ancestors that possessed wings but not possessing them in the current species

How does Wolbachia interact with insects?

It alters the sex ratio to favor females and causes insects w/in the same specie to be reproductively incompatible if they do/don't harbor the bacteria

Define: Parthenogenisis

Populations that don't contain males; the females reproduce asexually

What percent of insects are herbivorous?

~50%

Initially, all insects were _______ consumers.

Saprophagous

As insects moved off the ground, they developed __________ and ___________ structures to avoid falling from plants.

Claws and adhesive pads

What percent of sap is nitrogen?

0.1-0.6%

Insects secrete ________, a solution of mostly water and sugars which is then ingested by other insects.

Honeydew

Plants will sometimes use odors to bring in _________ to help control another pest problem.

Parasitoids

Examples of plant defense include:

Trichomes, sap, latex, and chemicals