OCR Gateway Biology B2 Flashcards

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Questions and Answers

Why are classification systems important?

They help us to understand how organisms are related.

What is a natural classification system?

They are classification systems based on the evolutionary relationships and the genetic similarities between organisms.

What are artificial classification systems?

They are classification systems based on appearance rather than the genes of organisms.

What is a genus?

A group of closely related species. Signup and view all the answers

What is a species?

A group of organisms that can breed together to produce fertile offspring. Signup and view all the answers

Why can it be difficult to classify animals?

Many organisms have characteristics which fall into more than one group. Signup and view all the answers

Why do classification systems change over time?

Scientists find new species and DNA sequencing reveals more about evolutionary relationships. Signup and view all the answers

What are evolutionary trees?

Diagrams which show evolutionary relationships and common ancestors. Signup and view all the answers

What is the binomial naming system?

A two-part Latin name for species. Signup and view all the answers

Why is the binomial system used?

It is used all over the world by scientists of different nationalities. Signup and view all the answers

What happens as you increase trophic levels?

The amount of energy, biomass, and number of organisms all decrease. Signup and view all the answers

What does each bar on a pyramid of biomass show?

The mass of the living material at that stage of the food chain. Signup and view all the answers

What is the problem with measuring biomass?

Biomass is the dry weight of an organism which requires killing and drying it before weighing. Signup and view all the answers

Why are pyramids of biomass sometimes inaccurate?

Some organisms may feed at more than one trophic level. Signup and view all the answers

Why is some energy lost at each of the stages of a food chain?

It is used for life processes such as respiration and movement. Signup and view all the answers

Why are most food chains no longer than 5 trophic levels?

So much biomass is lost at each stage that there would not be enough energy left to support another. Signup and view all the answers

What is the equation for efficiency of energy transfer?

efficiency = energy available at next level / energy available to previous level * 100. Signup and view all the answers

Study Notes

Importance of Classification Systems

Classification systems help comprehend the relationships between organisms.

Natural Classification Systems

Based on evolutionary relationships and genetic similarities among organisms.

Artificial Classification Systems

Focused on physical appearance rather than genetic data, primarily used for identification of organisms.

Genus

A category that groups closely related species together.

Species

Defined as a group of organisms capable of breeding together to produce fertile offspring.

Challenges in Classifying Animals

Many organisms exhibit traits belonging to multiple groups.
Asexual reproduction and hybridization complicate species classification.

Evolution of Classification Systems

New species discoveries and advancements in DNA sequencing alter classification.
Evolutionary relationships can be reevaluated based on newfound data, affecting how organisms are classified.

Evolutionary Trees

Diagrams illustrating evolutionary relationships, indicating common ancestors.
Closer common ancestors signify greater relatedness between species.

Binomial Naming System

Comprises a two-part Latin name; the first part indicates the genus, the second identifies the species.

Global Use of the Binomial System

Universal among scientists globally due to its Latin basis, allowing for clear communication across different languages.

Trophic Levels and Energy Transfer

Energy, biomass, and number of organisms decrease as trophic levels increase.

Pyramids of Biomass

Each bar represents the mass of living material at a specific food chain stage.

Challenges in Measuring Biomass

Biomass measurement requires killing and drying organisms, which raises ethical concerns.

Inaccuracies in Biomass Pyramids

Some organisms operate at multiple trophic levels, leading to potential discrepancies in biomass representation.

Energy Loss in Food Chains

Energy is lost at each step due to metabolic processes like respiration and movement, not all of which contributes to growth.

Limitations of Food Chain Length

Most food chains do not exceed five trophic levels due to energy loss, which limits the energy available for higher levels.

Energy Transfer Efficiency Equation

Efficiency = (Energy available at next level / Energy available to previous level) x 100.

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Description

Test your knowledge with these flashcards focusing on classification systems in biology. Understand the differences between natural and artificial classification systems and why they are essential for studying organisms. Perfect for Biology B2 students preparing for their exams.