LECTURE 26 - Do Species Matter?

Question 1

biological species concept explanation

Answer 1

ME : the Biological Species Concept says that if a group of organisms can interbreed and make healthy babies, they belong to the same species. If they can’t do this with other groups, they’re considered different species. It’s all about who can have babies with who!

Question 2

biological species concept def

Answer 2

“Groups of actually or potentially interbreeding
natural populations, which are reproductively isolated
from other such groups”

Question 3

species problem

Answer 3

But this concept has some challenges. Sometimes, animals that are labeled as different species can still have babies together, like a horse and a donkey having a mule. Also, it doesn’t work well for creatures that don’t have males and females, like some plants or bacteria. Fossils of animals from a long time ago are also tricky to sort into species using this concept.

So, scientists have come up with other ways to define species. Some look at the creatures’ DNA or genes, some focus on where they live and what they eat, and others just compare how similar they look overall.

Despite these challenges, the biological species concept is still the most common way we decide what a species is, even though it doesn’t always solve the “species problem” perfectly.

Question 4

do species matter?

Answer 4

YES
1. They’re real: For most of the animals and plants we see every day, the idea of different species makes sense. It’s like saying a dog is different from a cat.

2. They help us understand diversity: Thinking about species helps scientists and researchers understand how different living things are related and how they’re unique.
3. They give us labels: Imagine if we didn’t have names for different animals and plants. It would be really confusing! Species labels help us communicate about the different kinds of life on Earth.
4. They have a history: Scientists have been studying species for a long time. Charles Darwin, a famous scientist, wrote a book called “On the Origin of Species,” which helped us understand how species change over time.
5. They’re crucial for conservation: We use species to help protect and save animals and plants that are in danger. There’s a big list called the IUCN Red List, which keeps track of species that need help.
6. They’re part of biodiversity: Biodiversity is like a puzzle with different pieces. Species are one of those pieces. They help keep our environment healthy and balanced.
7. They’ll still matter: Even as we get better at studying genetics, species will still be important. We’ll keep using the concept of species to understand and protect the incredible variety of life on our planet.

Question 5

How do we count the numbers of species?

Answer 5

You need to consider the area:
backyard, the local government area, the state, the country?
* How much of the area can be sampled?
* Consider Which kinds of organisms will be counted
* Time of day / season / weather conditions

Methods:
* counts for large / conspicuous animals or plants
* traps for small / shy species – e.g., many insects
* cameras / remote sensors – e.g., for small vertebrates
* genetic methods (e.g., eDNA) for cryptic species [phenotypically highly similar species]

Question 6

Species richness def

Answer 6

= number of species in a sample (S)

Question 7

Species diversity def

Answer 7

is a measure of the number of species (i.e.,
species richness) and the numbers of individuals of these species brought
together into a single index

Question 8

ME : difference between species richness and diversity

Answer 8

The sample from pond 1 has 100 insects comprising 10 individuals from 10 species
* The sample from pond 2 has 100 insects comprising 91 individuals of one species and a single individual from each of the remaining 9 species
* The two ponds have the same species richness (S = 10), but which pond has the
higher species diversity? Intuitively, it is pond 1: numbers are more even

Question 9

species diversity index

Answer 9

D : 1-Nmax /N
where N =
number of individuals in the sample and Nmax is the number of the most
abundant species
The sample from pond 1 has 100 insects comprising 10 individuals from 10 species
* The sample from pond 2 has 100 insects comprising 91 individuals of one species and a
single individual from each of the remaining 9 species
* Pond 1: 1 – 10 /100 D = 0.9
* Pond 2: 1 – 91 / 100 D = 0.09

Question 10

alpha diversity

Answer 10

the number of
species within a particular areas or
habitats

ME: local diversity. It measures the number of species in a specific, small area like a pond, a forest, or a park. It tells you how many different species you can find in one place. For example, if you’re studying the types of birds in a single forest, the number of different bird species you find there represents the alpha diversity of that forest.

Question 11

beta diversity

Answer 11

the difference in
species between areas or habitats/ turnover diversity

ME: For instance, if you compare the kinds of plants in a meadow and a nearby forest, you’re looking at beta diversity. It tells you how much the species composition changes between different habitats.

Question 12

gamma diversity

Answer 12

the number
of species from all areas or habitats
combined/ regional diveristy

ME: If you were to study all the different types of fish across all the lakes in a whole country, you’d be exploring gamma diversity.