Classifying Environments

Question 1

John ray

Answer 1

1686
First attempt at a definition of a species
Based on how they look and they stay the same - fixed

Question 2

Carl Linnaeus

Answer 2

1735
Idea of taxonomical hierarchy based on shared physical characteristics

Question 3

Ernst Mayr

Answer 3

1942
Organisms within a species can reproduce with one another
And they cannot reproduce with organisms of other species

Question 4

Why and how do DNA sequences change over time

Answer 4

1. Replicating organisms and the DNA in them increase in numbers exponentially
2. there are not enough resources or space in any environment to support unlimited population growth. At some point there will be competition for these resources – a ‘struggle for existence’.
3. Random mutations

Question 5

What is a species - Ernst mayr

Answer 5

A group of organisms that can interbreed and produce fertile offspring

Question 6

Problems with Ernst Mayr ‘s definition of a species

Answer 6

Hybrids- sub-species
Quite animal centric
Does not explain how species originate
Bacteria - most abundant and diverse organisms on the planet do not interbreed

Question 7

George Simpson

Answer 7

1951
Members of a species share an evolutionary process

Question 8

Adaptive evolution

Answer 8

Selection will cause a permanent change in the composition of the population

Question 9

Adaptive trade-offs

Answer 9

Traits that evolve and are adapted to one environmental condition mean the organism is less adapted to others…

Question 10

Operational taxonomic units

Answer 10

Practically a % DNA similarity level is used ~98% to collect samples into the same ‘species’

To avoid misrepresentation – these collections of samples with DNA >98% similarity are called

Operational taxonomic units (OTUs) or molecular operational taxonomic units mOTUs

Or phylotypes = a biological type that classifies organisms based on their genetic characteristics and evolutionary relationships

Question 11

Environmental metabarcoding

Answer 11

Ancient ecosystems
Plant-pollinator interactions
Diet analysis
Invasive species detection
Pollution response
Air quality monitoring

Question 12

Neutral ecology

Answer 12

Different species are functionally equivalent
Different due to chance

Question 13

Chance processes that change evolution

Answer 13

Bottleneck effect
Founder effect

Question 14

Niche

Answer 14

A concept of an organism’s environmental tolerances and resource requirements
Eg temperature, pH, pollution, prey, nest locations
Multi-dimensional

Question 15

Resource vs conditions

Answer 15

Conditions are NOT competed for eg temperature
Resources are competed for eg space , food

Question 16

Measuring fitness in a particular niche

Answer 16

Ability to leave viable offspring

Question 17

Fundamental niche

Answer 17

The environmental parameters across which an organism can survive

Question 18

Realised niche

Answer 18

The environmental parameters across which an organism can reproduce

Question 19

What do ecologists use to define niches

Answer 19

Ordination analyses - collapse multiple dimensions into 2 main ones that show the main environmental patterns

Question 20

Ecosystem engineer

Answer 20

Any species that creates, significantly modifies, maintains or destroys a habitat

Question 21

Allogenic engineers

Answer 21

Change a physical part of the environment

Question 22

Autogenic engineers

Answer 22

Creates habitats biologically eg coral

Question 23

Crepuscular

Answer 23

Only active dawn or dusk

Question 24

Cathemeral

Answer 24

Active all times of the day

Question 25

Diurnal

Answer 25

Active during the say

Question 26

Nocturnal

Answer 26

Active at night

Question 27

Niche construction

Answer 27

Trait must be heritable and correlated with reproductive success

Question 28

The Crabtree effect

Answer 28

Yeast- kills the competition and creates a new niche dimension (high ethanol concentration) when anaerobically respires

Question 29

Population

Answer 29

A group of the same species in the same place at the same time

Question 30

Population change

Answer 30

A function of birth and death rate

Question 31

Numbers now

Answer 31

Numbers before + proportional change of [numbers before] + [Immigration – Emigration]

Question 32

Carrying capacity

Answer 32

defines the maximum number of individuals it will support… think limited space or resources

Question 33

Number now (carrying capacity)

Answer 33

Numb before + Numb before x proportional change x f [carrying capacity]

Question 34

What is used to estimate birth and death rates

Answer 34

Life tables

Question 35

Speciation

Answer 35

If populations remain disconnected for sufficient time, then either adaptation to different niches and/or neutral processes may/will lead to differential evolutionary trajectories … At some point these populations are unable to interbreed and/or they become genetically divergent … this leads to the two populations being sufficiently distinct to be classed as different species since they have sufficiently different evolutionary histories

Question 36

Life history tables

Answer 36

For each ‘cohort’ each generation/time Number born Number survive Number offspring Calculate these and make proportions etc to derive birth and death rates This can allow an estimate of the basic reproductive rate of the population

Question 37

Classification of survivorship curves

Answer 37

type 1: mortality concentrated toward the end of the maximum life span (humans, pets) type 2: constant mortality rate from birth to maximum age type 3 : extensive early mortality, but a high rate of subsequent survival – typically many offspring produced (most common in nature)