Topic 25: Do species matter?

Question 1

Explain the most accepted definition for species and others

Answer 1

• groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
• Genetic species: if DNA not similar → different species
• Ecological species: differ in ecological interactions
• Phenetic species: overall similarity

Question 2

What are some problems with the concept of species?

Answer 2

• Many species hybridise → offspring are still viable in some cases
• Not applicable to asexual organisms and fossil taxa
• Hard to fully agree on the range of particular species

Question 3

Explain why species do matter

Answer 3

• Easy to name and label different organisms
• “Real” concept for most familiar organisms
• Foundation to continue thinking about biological variation
• Foundation for local, state, national and international conservation efforts
• Central to biodiversity conservation

Question 4

What is the underlying rule for sampling and estimation results?

Answer 4

The more effort, the more sampling, the more likely to capture more rare species

Question 5

What factors to consider before estimating the number of species?

Answer 5

• Define the area, times and taxa
• Decide the portion of the area
• Times of the day, seasons and weather are important.

Question 6

List some counting methods for particular species

Answer 6

• Count: large/conspicuous animals or plants
• Traps: small/shy species e.g. insects
• Cameras/remote sensors for small vertebrates
• Genetic methods for cryptic species

Question 7

Define species abundance, species richness, species diversity

Answer 7

• Species abundance: total number of individuals in a sample
• Species richness: total number of species in a sample
• Species diversity: the distribution of individuals between species in the sample
  + The more even the individuals are distributed, the more diverse that sample is
  + Number of individuals and number of species brought together in a single index

Question 8

Identify and describe 3 types of species diversity

Answer 8

• Alpha - local diversity: number of species within a particular area of habitat
  
  • e.g. number of species in my backyard
• Beta - turnover diversity: difference in the number of species between areas or habitats
  
  • e.g. difference in species number between my backyard and my neighbor’s
• Gamma - regional diversity: number of species in all areas/habitats combined
  
  • e.g. total number from my and my neighbor’s backyard

Question 9

How many species are there and how are they distributed?

Answer 9

• 1.5-1.82 millions - named and described → many more to come
• Many of the species are insects and invertebrates, also cryptic organisms
• Larsen et al (2017) estimation: around 2.238 billion species on Earth and 70-90% are bacteria

Question 10

What are some ways to estimate total number of species including the ones not discovered yet?

Answer 10

• Extrapolate from current rates of discovery
• Extrapolate from diversity in well surveyed areas to poorly surveyed ones
• Expert knowledge estimates