4 - Biodiversity, Evolution and Disease

What is one adaptation of Marram grass that reduces water loss?

Leaves are rolled longitudinally trapping humid air inside.

Why is thick waxy cuticle important for Marram grass?

It reduces evaporation of water from the leaf surface.

How do stomata in Marram grass contribute to its adaptation?

They are located on the lower epidermis inside the rolled leaves, protected by enclosed air space.

What is a characteristic of the stomata in Marram grass?

Stomata are in pits in the lower epidermis, covered by hairs to reduce air movement.

What is a key feature of the mesophyll in Marram grass?

It is very dense with few air spaces, reducing the surface area for evaporation of water.

What does it mean for cacti to be succulents?

They store water in their stems, which become fleshy and swollen.

What advantage does a low water potential in xerophyte leaf cells provide?

It reduces evaporation of water from cell surfaces by lowering the water potential gradient.

Give one adaptation of roots for survival in arid conditions.

Roots can be very long, allowing them to reach water deep in the soil.

What is another adaptation of roots for arid conditions?

Roots can be widespread to absorb water from a large area when it rains.

What does classification refer to?

The process of grouping living organisms into categories.

Why do scientists classify organisms?

It simplifies identification and predicts characteristics across related species.

What is taxonomy?

A hierarchical system for grouping organisms into smaller categories.

What are the eight taxonomic groups from largest to smallest?

Domain; Kingdom; Phylum; Class; Order; Family; Genus; Species.

What is the binomial naming system?

A two-name system for identifying organisms, consisting of genus and species.

Why is the binomial naming system important?

It provides a universal scientific name that avoids confusion from common names.

What are the five kingdoms in classification?

Prokaryotae, Protoctista, Fungi, Plantae, Animalia.

What are the general features of prokaryotae?

Unicellular, no nucleus, a ring of naked DNA, no complex feeding mechanisms.

What are the general features of protoctista?

Mainly unicellular, nuclei, some have chloroplasts, diverse nutritional methods.

What are the general features of fungi?

Unicellular or multicellular, cell wall of chitin, no chlorophyll, saprotrophic.

What are the general features of plantae?

Multicellular, chlorophyll present, cellulose cell walls, autotrophic.

What are the general features of animalia?

Multicellular, no chloroplasts, heterotrophic, capable of movement.

What are the three domains of classification?

Bacteria, Archaea, Eukarya.

Why are three domains preferred to five kingdoms?

They fit better with phylogeny and highlight differences between groups.

What differentiates eukarya from bacteria and archaea in terms of ribosomes?

Eukarya has 80s ribosomes; Bacteria and Archaea have 70s ribosomes.

What is phylogeny?

The evolutionary relationships between organisms.

What are phylogenetics?

The study of evolutionary history and relationships among organisms.

What is a phylogenetic tree?

A diagram illustrating the evolutionary history and relationships of groups.

What is one advantage of phylogenetic classification?

It connects groups based on their relationships rather than characteristics.

What is evolution?

The theory explaining how organisms change over time through natural selection.

What key observation did Darwin make to support evolution?

Organisms best suited to their environments are more likely to survive and reproduce.

What did Darwin observe about the Galapagos finches?

They had different beak shapes adapted to the food sources on different islands.

How did Darwin relate the shape of finches’ beaks to their environment?

He linked beak shape to the type of food available, influencing survival and reproduction.

Who was Alfred Wallace?

A contemporary of Darwin who independently developed a theory of evolution.

What was controversial about Darwin's theory when it was published?

It challenged the existing views on the age of the Earth and the process of species change.

What are the three main sources of evidence for evolution?

Paleontology, comparative anatomy, and comparative biochemistry.

What is paleontology?

The study of fossils and their implications for Earth's distant past.

What evidence for evolution can be observed in the fossil record?

Simple organisms are found in older rocks, while complex organisms are in newer rocks.

Why is the fossil record incomplete?

Not all organisms fossilize, conditions may not be suitable, or fossils may be destroyed.

What does comparative anatomy study?

The similarities and differences in the anatomy of different species.

What is a homologous structure?

A structure with a common underlying design, but has different functions in different species.

What evidence do homologous structures provide?

Evidence for divergent evolution from common ancestors.

What is comparative biochemistry?

The study of similarities and differences in biological molecules across species.

What molecules can be analyzed in comparative biochemistry?

Cytochrome C and ribosomal RNA.

What are two types of variation within organisms?

Interspecific variation and intraspecific variation.

What is interspecific variation?

Variation between organisms of different species.

What is intraspecific variation?

Variation between organisms of the same species.

What are the causes of genetic variation?

Genetic causes include alleles, mutations, meiosis, and sexual reproduction.

How do alleles contribute to genetic variation?

Different alleles result in various traits and characteristics among individuals.

What do mutations do in terms of genetic variation?

Mutations change DNA sequences, potentially affecting traits and characteristics.

How does meiosis promote genetic variation?

Meiosis leads to unique combinations of genes through independent assortment and crossing over.

What is the role of sexual reproduction in genetic variation?

It combines genetic material from two parents, generating genetically unique offspring.

What does the term 'chance' refer to in genetic variation?

The random nature of which gametes combine during fertilization.

Why is there greater variation in sexually reproductive organisms?

Sexual reproduction leads to more genetic combinations compared to asexual reproduction.

Which group is more affected by environmental changes, animals or plants?

Plants, as they are generally immobile.

Give an example of purely environmental variation.

Presence or absence of scars, which cannot be inherited.

What typical causes variation within a population?

Both genetic and environmental factors contribute to variation.

Give an example of a characteristic affected by genetic and environmental factors.

Height; influenced by genes and nutrition.

In what two groups can characteristic variation data be sorted?

Discontinuous and continuous variation.

What is another term for discontinuous variation?

Discrete variation.

What defines discontinuous variation?

Variation that can only fit into specific categories.

Give an example of discontinuous variation.

An animal's sex or human blood group.

What causes discontinuous variation?

Characteristics determined by a single gene.

How is discontinuous variation displayed graphically?

Using a bar chart.

What is continuous variation?

Variation that can take any value within a range.

Provide an example of continuous variation.

Height or mass.

What causes continuous variation?

Multiple genes (polygenes) and environmental influences.

How is continuous variation displayed graphically?

Using histograms or frequency tables, often resulting in a bell curve.

What distribution do continuous variations typically show?

Normal distribution.

What is normal distribution?

Data creating a bell curve when plotted, with symmetrical characteristics around the mean.

What are the characteristics of normal distribution?

Mean, median, and mode are equal; bell curve shape; most values near the mean.

What does standard deviation measure?

The spread or variability of the data.

What does a high standard deviation indicate?

A large amount of variation in the data set.

What does a low standard deviation indicate?

A small amount of variation in the data set.

What are the typical percentage values for the first three standard deviations in a normal distribution?

1 SD - 68%, 2 SD - 95%, 3 SD - 99.7%.

What do the symbols in the standard deviation formula represent?

σ - Standard Deviation, ∑ - Sum of, x - measured value, x̅ - mean value, n - total values.

What is the purpose of the Student's t-test?

To compare the averages of data values between two populations.

What is Spearman's rank correlation coefficient used for?

To analyze the relationship between two data sets.

Why are statistical tests important?

To assess whether observed relationships or outcomes are due to chance.

What is the null hypothesis in a Student's t-test?

There is no significant difference between the two populations.

What is the null hypothesis in Spearman's rank?

There is no significant relationship between the two data sets.

What do degrees of freedom in a t-test indicate?

It reflects the amount of independent data collected.

How is significance determined in a Student's t-test?

By comparing the 't' value to significance tables based on the degrees of freedom.

What does the probability value in significance tables indicate?

The likelihood that the observed effect is due to chance.

How is significance determined in a Spearman's rank test?

By comparing the correlation coefficient to significance tables based on sample size.

What are adaptations in biology?

Characteristics that enhance an organism's survival and reproduction.

What are the three types of adaptation?

Anatomical, behavioral, and physiological adaptations.

What is an anatomical adaptation?

A physical feature that enhances survival.

What is a behavioral adaptation?

An inherited or learned action that increases survival chances.

What is a physiological adaptation?

An internal process that aids survival.

Give an example of an anatomical adaptation.

Camouflage for blending with the environment.

How does Marram grass minimize transpiration?

Through curled leaves that reduce the exposed leaf area.

What role do hairs play inside Marram grass leaves?

They trap moist air, increasing humidity around the leaf surface.

What is one behavioral adaptation example?

Migration to avoid unfavorable conditions.

What are the two main types of behavioral adaptations?

Innate and learned behaviors.

What defines innate behavior?

Instinctive actions inherited through genes.

What defines learned behavior?

Behavior developed through experience and observation.

What is an example of a physiological adaptation in plants?

Water storage in succulents like cacti.

What is convergent evolution?

When unrelated species develop similar traits due to similar environments.

What causes convergent evolution?

Similar environmental pressures experienced by unrelated organisms.

What is natural selection?

The process where organisms well-suited to their environment survive and reproduce.