ENTM 010: Evolution and Success of Insects Vocab

Detritivores/Saprophages

insects that feed on dead things and contribute to decomposition (half of insect species)

Predators and Parasites

Feed on plants (other half of insects)

Why are insects so successful?

1. Tough, waxy, water repellant exoskeleton protects against water loss, pathogens, predators, parasites, physical shock

2. Muscle attachment + flight

3. Smaller size allows for hiding, fewer resources

4. Large and rapid reproductive rate

5. Short development time and life cycles allow for mutations

6. Extensive metamorphosis development allow for reduced competition between adults and larvae

7. protected from harsh environmental conditions

8. Specialized + adapted appendages for feeding and movement

9. Social behavior —> survive through difficult periods, division of labor

10. Genetic species isolation methods that prevent cross-breeding, keeps traits within species.

What is the first step of insect evolution?

The development of thorax and a definite insect form —> previously only had abdomen and a cephalothorax

What is the second step of insect evolution?

The development of wings and a rudimentary ability to fly —> basically glided (200-350 million years ago)

What is the third step of insect evolution?

The development of wing-flexing mechanism —> allowed wings to fold over thorax and abdomen when not in use, allowed insects to run better and fit into smaller spaces

What is the fourth and final step of insect evolution?

The development of holometabolism/complete metamorphosis—> allowed insects to explore new resources and reduce competetion between juveniles and adults

What is evolution?

A change in gene frequency in a population of individuals. A genetic phenomena of populations

What are other ways natural selection can occur?

1. Killed off by disease

2. Killed off by parasitism

3. Harsh environments

4. inter-intraspecific competition for resources (food, shelter, mates, etc)

What is artificial selection?

When humans act as the selection agent, specifically when humans breed things for certain qualities or characteristics. Gene frequencies usually change much faster than natural selection.

What is Holometabolism?

Complete metamorphosis that seperates out juveniles and adults, juveniles responsible to eat and grow, where adults disperse and reproduce

What is a Phenotype?

Physical characteristics, basically what you see

What is a genotype?

The genetics behind what you see

What are the major mechanisms of evolution?

1. Mutations

2. Natural Selection

3. Natural forces (predation, parasitism, disease, competition for resources)

4. Survival of the fittest (fittest = survive and produce kids)

What is Genetic drift?

Chance event(s) that alter gene frequencies from generation to generation.

What are the possible effects of genetic drift?

Can result in the Founder effect.

Can result in skewed-sex scenarios

Can result in a Bottleneck effect

What is the Founder Effect?

When a new colony is started by a few members of the original population.

What is the Bottleneck effect?

When a large portion of a population suddenly dies out and lessens the genetic variety significantly.