Lecture 1: Insect Ancestry

Question 1

what phylum are insects?

Answer 1

Arthropods

Question 2

how many legs do insects have

Answer 2

no simple definition, differs from other arthropods in that

-usually has 6 legs at some point in its life

Question 3

how many body regions do insects have

Answer 3

-differs from other arthropods in that body is divided into three regions

Question 4

how many antennae do insects have?

Answer 4

differ from other arthropods in that head bears one pair of antennae

Question 5

how many wings?

Answer 5

differs from other arthropods in that in most adults throat 2 pairs of wings

Question 6

are all winged invertebrates insects?

Answer 6

YES

Question 7

how many described species of insects are there?

Answer 7

1 million

-between 2-20 million undescribed

Question 8

insects make up nearly __% of all species

Answer 8

80

Question 9

is the diversity of insects reflected in natural history books?

Answer 9

NO

Question 10

insects play a major role in ____

Answer 10

ecosystems

-ants are the predominant animal biomass in tropical forests

Question 11

insects furnish biology with examples: popular lab specimen:

Answer 11

e. g. Drosophila melanogaster

- in a lab you’ll probs work on an insects,

Question 12

they affect man in many different ways: diseases

Answer 12

• 600M people are affects by insect vectored diseases
• these diseases also affect livestock
• insects attack crops (15% lost worldwide), stored products (grain) and timber (housing)

Question 13

they affect man in many different ways: beneficial:

Answer 13

• flowering crops are pollinated by insects

- insects are often major biocontrol agents

Question 14

so insects are ___ (species and biomass) = successful and are consequently ____

Answer 14

NUMEROUS

-important (disease, crops, economic benefits)

Question 15

where did insects come from? they are ____

Answer 15

living fossils; they have remained unchanged since before the dinosaurs!

Question 16

the most abundant fossil insects are

Answer 16

Palaeodictyoptera (found in the carboniferous)

Question 17

insects are characterised by:

Answer 17

-distinct head + antennae + compound eyes
-thorax bearing 2 pairs of non-flexing wings
-an elongated 11-segmented abdomen + cerci
(This insect was NOT an active flyer - its wings are broad and long and that, coupled with the long cerci suggest it was a glider, not an active flyer)

Question 18

only modern groups you had which are similar to we have now

Answer 18

• mayflies - ephemeroptera

- dragonflies - Odonata

Question 19

cerci

Answer 19

tail streamers

Question 20

the oldest known fossil insects are from

Answer 20

Devonian –> Collembolan - springtails