Bio120- lab chapter 1

Question 1

What are ‘Arthropods’?

Answer 1

Arthro: joint, pod: leg

Examples are insects

Question 2

What are three main sections of Insects?

Answer 2

1. Head
2. Thorax
3. Abdomen

From thorax, there extends three pairs of legs and usually one or two pairs of wings.

Question 3

Over half of the identified species are what?

Answer 3

Insects. (Among 1.9 million living organisms)

Question 4

What is a trait?

Answer 4

It is a characteristic

Question 5

What is an adaptation

Answer 5

A trait that contributes to fitness by improving an individual’s chances of surviving or reproducing.

An adaptation can be both physical (eg..colour of wings) or behaviour (ex: attraction to certain smells)

Question 6

What are the two types of Adaptations?

Answer 6

Physical and Behaviour

Question 7

What are two ways adaptation word can be used as?

Answer 7

1. An adaptation: As a trait (Ex: bat wing is an adaptation for flight)
2. To adapt (Verb) : Referring to the evolutionary process through which such (adaptations) arise.

(Ex: Bats acquired wings through adaptation to their environment or bats adapted to their environment by evolving wings)

Question 8

Who and in what year, proposed the mechanism for the process of adaptation?

Answer 8

In 1859, Charles Darwin, in his book The Origin of Species, proposed the mechanism for the process of Adaptation called ‘Natural Selection’

Question 9

How are new traits and new combinations created in populations according to darwin?

Answer 9

According to Darwin,
Mutations (genetic ‘errors’) and recombination (The mixing of genes through sex) are the reasons behind new traits and new combinations

Question 10

How does new traits and new combinations help? I.e how does mutations (genetic error) and recombination ( Mixing of genes through sex) help?

Answer 10

They result in some individuals who possess traits that help them to survive and reproduce better (and have more off springs) than other individuals.

These species are known to have more fitness

Question 11

What is fitness?

Answer 11

It can be measured as the number of offsprings an individual produces relative to other individuals in a population

Question 12

How does Natural selection result?

Answer 12

It results from variation among individuals in the number of surviving offspring they contribute to the next generation

Question 13

What are heritable traits?

Answer 13

These are the high-fitness traits that will be present in a greater proportion of individuals in the next generation. They are passed on from parents.

Question 14

Until when is natural selection and inheritance repeated?

Answer 14

Until the advantageous trait is present in almost all individuals

Question 15

What is Evolution

Answer 15

The change of traits (Repeat of natural selection and inheritance) , the change over generations in the proportion of individuals with a certain trait is called Evolution.

Question 16

What is adaptation?

Answer 16

Fitness enhancing trait that has spread through population by natural selection.

Question 17

How do complex adaptations occur?

Answer 17

Through many traits combined over many generations.

Question 18

What are three criteria to evolve by natural selection?

Answer 18

1. The trait is heritable
2. There is a variation between individuals within the population for the trait
3. Variations in the trait lead to some individuals leaving more offspring in the next generation than others. (Some individuals have higher fitness then others)

Question 19

Do all differences in population the result of natural selection?

Answer 19

No

Question 20

What are the reasons for differences in populations apart from natural selection?

Answer 20

1. Genetic Drift: Populations changing randomly by random processes
2. Gene flow: Influx of migrants from other populations.

Question 21

What is phylogeny?

Answer 21

It is evolutionary history and relationships) of the species in question.

Question 22

How is phylogeny useful?

Answer 22

Knowledge of phylogeny enables biologists to determine when and what sequence different traits evolve.

Question 23

What do scientists do when they find an interesting trait?

Answer 23

They come up with atleast one hypothesis of the trait might increase fitness of individual (or in other words, they come up with a possible function for why the trait might evolve)

Hypothesis is made from some knowledge from the organisms behaviour, organism’s habitat, behaviour and life style.

After the hypothesis is made, the next step is to test it.

Question 24

What are hypotheses on adaptations divided into?

Answer 24

they are divided into 2 parts

1. Viability: Success in survival and acquisition of food)

2.competition for mates.

Some adaptations enhance both.

Question 25

What do you need to confirm a hypotheses

Answer 25

An empirical evidence

Question 26

How do you test for a hypotheses

Answer 26

Observation or Experiment

Question 27

What is viability selection?

Answer 27

Natural selection arising from variation in viability (ex: locomotion, parasite avoidance etc)

Question 28

Name some viable selections:

Answer 28

1. Camouflage: Blue winged grasshopper blending in well with stones and sand. 2. Life in water: Aquatic insects have bodies and legs specially shaped to facilitate locomotion in their aquatic environment 3. Feeding: Insects have adapted to particular diets by evolving specialized mouthparts

Question 29

Name some examples of viable selection in feeding

Answer 29

1. Mandibles (Powerful jaws of ants) for biting and tearing 2. Stylet (Mosquito tubes) for piercing and sucking 3. Proboscis: long tongue of butterflies

Question 30

What is Sexual Selection?

Answer 30

natural selection arising from variable mating success

Question 31

What differences does sexual selection often result in?

Answer 31

differences between males and females in secondary sexual characteristics (i.e sexual characteristics other than ovaries and testes.)

Question 32

What is sexual dimorphism?

Answer 32

Differences between the sexes in the shape or size of the body.

Question 33

What are the two principal mechanism of sexual selection?

Answer 33

1. Intrasexual competition 2. Mate choice

Question 34

What is Intrasexual competition?

Answer 34

In many species, male animals fight for access to females, The male that wins has more offspring. Ex: Male European earwigs have large projections called forceps which they use in competition with other males.

Question 35

What is mate choice?

Answer 35

In many species, females and/or males are choosy. It is said to increase fitness of the chooser by enabling to mate only with healthy individuals. Attractive individuals produce more offspring, hence animals have adapted to the preferences of the opposite sex by adapting various structures.

Question 36

What is complete metamorphism?

Answer 36

Butterflies undergo a series of profound changes in body form, behaviour and lifestyles. This process is known as metamorphism.