Module 3 - Biodiversity And Evolution Flashcards
What is biodiversity? Is it only viewed at one level?
Biodiversity is the range of organisms. It can be considered at many levels - in a habitat, between species and in genetic variation within a species.
Why do we sample organisms?
- quicker than counting all organisms
- gives representation of a whole habitat
How do we ensure that a sample takes place at random?
- use a random number table
OR - take samples at regular distances
In what ways do we sample plants?
1) random quadrats: quadrat placed at random. Abundance is measured by either % cover (by counting the squares) or by using a point frame.
2) transect: line taken across a habitat, record plants touching line at set intervals
What are three ways of sampling animals?
1) sweep netting: sweeping a net through an area. Any organisms caught are put on a white sheet and counted.
2) collecting from trees: white sheet is placed under branch while branch is shaken so any animals fall onto the sheet.
3) pitfall trap: container buried just under surface of soil. Any animals moving through plants will fall into container.
Define ‘species richness’
Species richness: number of species in a habitat
Define ‘species evenness’
Species evenness: relative abundance of individuals in each species.
How can species evenness be calculated in animals?
Total population = (C1 x C2) / C3
C1 -> first sample of animals
C2 -> second sample
C3 -> already marked animals caught on 2nd sample
Why is the simpson’s diversity index good?
It’s good because it takes into account both richness and evenness.
What does a high diversity index value indicate?
Diverse habitat, stable, can withstand change.
What does a low diversity index value indicate?
Few species. Small changes could damage/destroy the habitat.
Define ‘taxonomy’
Taxonomy - the study of classification
Define classification
The grouping of living organisms according to shared similarities
Define phylogeny
The study of evolutionary relationships between organisms
describe the classification of species into
the taxonomic hierarchy
- kingdoms are sorted into domains
- phyla are sorted into kingdoms
- classes are sorted into phyla
- orders are sorted into classes
- families are sorted into orders
- genus are sorted into families
- species are sorted into genus
What are the five kingdoms?
Prokaryotes, protoctists, fungi, animals, plants
Describe the characteristics of prokaryotes
- no nucleus
- no membrane bound organelles
- smaller ribosomes
- respiration in mesomes
Describe the characteristics of protoctists
- eukaryotes
- mostly single called but some multi cellular
- autotrophic and heterotrophic
- basically everything that doesn’t fit into any other group
Describe the characteristics of fungi
- eukaryotes
- walls made of chitin
- saprophytic
Describe the characteristics of animals
- eukaryotes
- heterotrophic
Describe the characteristics of plants
- eukaryotes
- autotrophic
- cellulose cell wall
- permanent vacuole
What does saprophytic, autotrophic and heterotrophic mean?
Saprophytic: nutrition by decaying organic matter
Autotrophic: nutrition by photosynthesis
Hetereotrophic: nutrition by digesting organic matter
What system is used to name each species?
The binomial system. Two names in Latin - the genus name and the species name.
What is the dichotomous key?
The dichotomous key is a series of questions with alternate answers to help you identify a specimen. each question has a yes or no option.
Apart from the five domains classification, what is the other main system?
The three domains system. Idea that prokaryotes can be divided into bacteria and archaea
What does variation mean?
The difference between individuals.
What are the two different types of variation?
Continuous variation and discontinuous variation.
What is continuous variation?
No defined categories. Two extremes and a large number of intermediate values between them. Eg height in humans, length of leaves on an oak tree.
What is discontinuous variation?
Two or more distinct categories with no intermediate values between them. Eg sex (male/female)
What causes variation?
- genetic variation: no combinations of alleles are exactly the same (unless identical twin)
- environmental factors: eg weight, direction of plant growth
What are adaptations?
Features that enhance survival
What is natural selection?
An organism that has beneficial characteristics caused by a mutants toon will be at an advantage and will more likely survive and pass on it’s beneficial characteristics.
What is speciation?
Formation of a new species.
What causes speciation?
- geographical separation
- reproductive barriers within the population eg behavioural changes or physical changes
What evidence is there for evolution?
- fossils: appearing in rocks over a long period of time
- biological molecules: two closely related species will have identical/v similar biological molecules
- DNA: the more differences in DNA, the further back in time they evolved.
What two different types of conservation are there?
Conservation in situ and conservation ex situ.
What is conservation in situ?
Conserving a species in it’s normal environment eg passing legislation stop activities such as hunting and conservation parks
What is conservation ex situ?
Conservation outside normal environment. Encourages the breeding of endangered species. Seeds can be collected and stored in huge numbers.
What is CITES?
“Convention on international trade in endangered species”. It regulates and monitors international trade in selected species.
What is the convention on biological diversity?
It promotes sustainable development and encouraged ex situ conservation.
Produced the EIA - avoid/minimise any adverse effects on biological diversity
Define ‘species’
Group of individual organisms that are very similar in anatomy, appearance and physiology and whose members are able to interbreed to produce fertile offspring.
How do fossils provide evidence for evolution?
Fossils show changes throughout many years
It’s possible to date fossils
