L2: Species, populations & niche

Question 1

What is taxonomy?

Answer 1

The name for classifying and naming organisms.
It takes into account what they look like.

(Lomolino, 2010)

Question 2

What is systematics?

Answer 2

This classifies organisms based on their evolutionary relationships of organisms rather than just if they look different

(Lomolino, 2010)

Question 3

What is ecology?

Answer 3

How organisms interact with and are affected by the environment in which they live.

(Lomolino, 2010)

Question 4

What is trophic?

Answer 4

How energy flows in an ecological community.

Lomolino, 2010

Question 5

Species ->….

Answer 5

Species -> Population -> Communities -> Ecosystems -> Biosphere

Question 6

Kingdom…

Answer 6

Kingdom
Phylum 
Class 
Order
Family 
Genus 
Species

Question 7

Morphological species concept:

Answer 7

Identified by Linneaus

Organisms identified/classified based on their physical appearances (phenotypes).

Question 8

Biological species concept:

Answer 8

(Mayr, 2001)

defines a species as any population or group of populations whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring.

Question 9

Ecological species concept:

Answer 9

(Bybee-Feldman, 2012)

defines a species in terms of its habitat, the environmental resources it uses, and its developed set of characteristics (morphological, behavioural, physiological, etc), in the face of competition from other organisms.

Question 10

What are subspecies?

Answer 10

a taxonomic group that is a division of a species; usually arises as a consequence of geographical isolation within a species.

Question 11

What is a polytypic species?

Answer 11

a species that have a series of subspecies. Most of the widespread species are Polytypic.

Question 12

What is a monotypic species

Answer 12

A species that exists in just one form (no subspecies)

Do not form polytypic species.

Question 13

What is a population?

Answer 13

Krebs (1972)

A group of organisms of the same species occupying a particular space at a particular time.

Question 14

Malthus (1978) showed that:

Answer 14

All organisms have the inherent potential to increase their numbers exponentially.

Rate of change in a population
dN/dt=rN

dN/dt = change in number of individuals per change in time 
r = Malthusian parameter 
N = Population size (number of individuals)

It means that rate change of the population is proportional to the size of the population, where r is the proportionality constant.

Question 15

Human population grows at

Answer 15

nearly an exponential rate- however, because resources limit growth, and many environments are unsuitable, no organisms actually increase indefinitely.

Question 16

Limits of Distribution

Answer 16

1) Climatic barriers: temperature and precipitation
Saguaro cactus (Sonoran desert in Arizona and NW Mexico) in relation to winter temperature regime. Distribution limited by low temperatures (sensitive to temperatures below -7°C).

2) Physical barriers: high mountains, arid deserts, etc..
3) Geological barriers: soil chemistry and structure.
4) Historical factors: changes in the pattern of land masses over the surface of the Earth. Or the past expansion of ice masses.
5) Chance! The arrival of wind-borne insect or seeds.
6) Biological barriers: when an organism is subjected to increased predation, etc. Competition limits geographic ranges.

Question 17

What is a niche?

Answer 17

The total requirements of a population or species for resources and physical conditions.

Question 18

The ecological niche

Answer 18

The “ecological space” occupied by an organism where environmental conditions mean populations can survive without the need to immigrate.

Question 19

Fundamental niche

Answer 19

The niche a species could occupy if only limited by the environment, and not by interactions with other species, i.e there’s no interspecific competition and/or predation

Question 20

3 species segregate their realized niche at a more local scale.

Answer 20

D. deserti: only in sandy habitats
D. nelsoni; inhabits the core of the Chihuahuam desert
D. spectabilis: limited to grasslands

Question 21

Interspecific competition

Answer 21

Different species share the same resource—unless they can partition its use, one species may eventually out-compete the other. Example, grey squirrels and red squirrels in Britain. The realized niche of red squirrels is reduced—and so are red squirrel numbers. Interspecific competition is a factor affecting species diversity.

Question 22

Intraspecific competition

Answer 22

Individuals of the same species directly share the same resources leads to limitation of population size: seedlings may fail to grow under parent tree if deprived of light; plants in the desert are spaced apart as water is limiting; there many be competition for reproductive opportunities (rut in deer).

Question 23

What are cryptic species?

Answer 23

Species within a genus that are morphologically so similar that they cannot be distinguished by superficial features (sibling sp.).
E.g. animals that appear identical but are genetically quite distinct

Question 24

Who showed that all organisms have the inherent potential to increase their numbers exponentially?

Answer 24

Malthus (1978)

Question 25

Malthus (1978) showed what?

Answer 25

All organisms have the inherent potential to increase their numbers exponentially.

Question 26

Species Concept

Answer 26

refers to the meaning of species in nature and to their role in the household of nature. (Mayr, 2001)

Question 27

Issues with ecological species concept.

Answer 27

Can miss cryptic species.

Many taxa exploit overlapping resources, this is not a very robust species concept.

Question 28

Realized niche

Answer 28

The observed ecological space a species uses – subset of entire fundamental niche.