Adaptation and Extinction

Question 1

When did the first animal evolve?

Answer 1

600 million years ago.

Question 2

What were the earliest animals like?

Answer 2

Soft-bodied, marine suspension/detritus feeders.

Question 3

What caused the Cambrian Explosion?

Answer 3

More oxygenated seas.
Break-up of Pannotia.
Increasing shallow sea area.
More potential niches.

Question 4

What causes convergent evolution?

Answer 4

Similar selection pressures causing phenotypic convergence.

Question 5

Why do taxa resemble each other?

Answer 5

Traits arose early.
Traits arose in the nearest common ancestor.
Traits arose by convergence.

Question 6

Define adaptation.

Answer 6

The condition of organisms being well-equipped, both by structure and function or behaviour.

Question 7

Define evolution.

Answer 7

A change in allele frequency in a population from one generation to the next.

Question 8

Describe modern synthesis (neo-Darwinism).

Answer 8

The combined Mendelian theory of heredity and Darwin’s theory of evolution.

Question 9

What is the molecular clock?

Answer 9

Molecular evolution occurs at almost a constant rate - mutation number can be used to determine divergence times.

Question 10

Define genetic drift.

Answer 10

Allele frequencies changing randomly in a population from generation to generation.

Question 11

Define niche construction theory.

Answer 11

A population changes its environment giving itself and other species an ecological inheritance with altered selection pressures.

Question 12

What is Batesian mimicry?

Answer 12

An edible mimic deceiving predators by resembling a toxic model organism.

Question 13

Define pre-adaptation.

Answer 13

A structure’s function changing considerably without much change in the structure itself.

Question 14

Give an example of pre-adaptation.

Answer 14

Feathers in birds were used for insulation but were pre-adapted to act as aerofoils for flight.

Question 15

How do we recognise adaptations?

Answer 15

Character fits too well to its environment.
Appearance of a complex design.
Character helps animal survive/reproduce.

Question 16

What is an animal body plan?

Answer 16

An assemblage of morphological features shared among many members of a phylum level group.

Question 17

Define tagmatisation.

Answer 17

The specialisation of body segments to perform a specific function.

Question 18

Define convergent evolution.

Answer 18

The independent evolution of physiological or behavioural traits in organisms in different times or spaces.

Question 19

What is synergism?

Answer 19

Multiple stressors acting together resulting in a combined effect great than the sum of their separate effects.

Question 20

What are the 2 types of adaptation?

Answer 20

Animal’s action (behavioural) and physical.

Question 21

What are vestigial structures?

Answer 21

Features that were adaptations for the organism’s ancestor but have evolved to be non-functional due to environmental change.

Question 22

Define ecological development.

Answer 22

The influence of environmental factors on the expression of phenotypic traits.

Question 23

How long does it take for the human gut microbiome to fully form?

Answer 23

3 years.

Question 24

What host services does the gut microbiome provide?

Answer 24

Digestion of certain food compounds.
Production of bioactive molecules (vitamins).
Immune system stimulation.
Protection against pathogens.

Question 25

Define an organism’s ecological niche.

Answer 25

The place or function of a given organism within its ecosystem.

Question 26

When do organisms hibernate?

Answer 26

When reduced food availability coincides with low winter temperatures which increase metabolic energy demands.

Question 27

What are the main reasons for leaving hibernation?

Answer 27

To prevent infections from the gut microbiome, to restore stored energy and to reproduce.

Question 28

What are the 2 forms of defensive chemical production?

Answer 28

Synthesising toxins using metabolic processes or accumulating toxins from food.

Question 29

Why are organisms struggling to adapt during the Anthropocene?

Answer 29

The level of environmental change is exceeding the capacity of developmental, genetic and demographic mechanisms that populations have evolved to deal with change.

Question 30

Define over-exploitation in the context of extinction.

Answer 30

Harvesting species from the wild at rates faster than natural populations can recover.

Question 31

Why are species moving away from the Equator? At what rate is this occurring?

Answer 31

Due to global warming making lower latitudes uninhabitable. Species are moving at a median rate of 16.9km per decade!

Question 32

What are the current estimates for the number of species lost per year?

Answer 32

11,000-58,000 species.

Question 33

What is the tragedy of the commons?

Answer 33

The depletion and ultimately the collapse of a common but limited resource when individuals act selfishly to maximize personal gains.

Question 34

What is an island habitat, in a biological context?

Answer 34

A patch of suitable habitat surrounded by an unfavourable environment that limits the dispersal of individuals.

Question 35

Why are islands important?

Answer 35

They make up 5% of land area but contain 30% of world’s biodiversity hotspots and 50% of marine tropical diversity.

Question 36

Which animals are the first to colonise an island?

Answer 36

Those with good dispersal traits.

Question 37

As the number of species on an island increases, what happens to the likelihood of other species arriving?

Answer 37

The likelihood decreases.

Question 38

Define speciation.

Answer 38

An evolutionary process by which populations diverge to become distinct species.

Question 39

Define adaptive radiation.

Answer 39

Organisms diversifying rapidly from an ancestral species into a multitude of new forms to exploit empty niches.

Question 40

Define endemism.

Answer 40

The ecological state of a species being unique to a defined geographical location.

Question 41

What triggers island gigantism?

Answer 41

The ecological release from large competitors and predators.

Question 42

What triggers island dwarfism?

Answer 42

The ecological release from predators and resource limitation.

Question 43

What are some morphological adaptations to parasitism?

Answer 43

Structures for host attachment and penetration.

Dorso-ventral flattening (to avoid grooming).

Question 44

What are some physiological adaptations to parasitism?

Answer 44

Strong, impermeable cuticle (Nematodes).
Antienzyme production (Helminthes).
Reduction in sensory organs, nervous/digestive systems and locomotion apparatus.
High fecundity.

Question 45

How do parasites avoid the host immune system?

Answer 45

Molecular mimicry - an “invisibility cloak”.

Question 46

What are some parasitic behavioural adaptations?

Answer 46

Host finding behaviour.
Periodic behaviours - following a cyclic stimulus.
Host modifying behaviours.

Question 47

What is the Allee Effect?

Answer 47

Warder Allee (1885 -1955) observed that under-crowding and NOT competition limited population growth for some species. Examples include passenger pigeons.