Biology Unit 2 – Reproduction, Diversity & Ecology

These flashcards cover key concepts from Biology Unit 2, including asexual and sexual reproduction, genetic diversity, adaptations, species interactions, competition, energy flow, and keystone species.

What characterises asexual reproduction?

It involves one parent and produces genetically identical offspring (clones).

Which type of cell division is used by prokaryotes during asexual reproduction?

Binary fission.

Which type of cell division do eukaryotes use for asexual reproduction?

Mitosis.

Give two advantages of asexual reproduction.

Fast reproduction and no need to find a mate (also low energy cost).

Why is lack of genetic variation a disadvantage of asexual reproduction?

Because populations cannot easily adapt and may be wiped out by disease or environmental change.

Name the asexual method where a parent splits into two equal cells.

Binary fission.

What is budding?

A small growth develops on the parent and eventually separates to form a new individual.

Provide an example organism that reproduces by budding.

Yeast or hydra.

What is fragmentation in asexual reproduction?

The body splits into pieces, each of which can grow into a new individual.

Name an organism that reproduces by fragmentation.

Starfish (or corals).

What is produced during spore formation?

Hardy reproductive capsules (spores) that grow when conditions are favourable.

Define vegetative propagation.

The growth of new plants from stems, roots, leaves or runners without seeds.

Give an example of vegetative propagation.

Strawberries producing runners (or potatoes from tubers).

What is parthenogenesis?

Females produce offspring without fertilisation.

Name a species group that uses parthenogenesis.

Bees (or some reptiles).

How many parents are involved in sexual reproduction?

Two parents.

By what process are gametes formed?

Meiosis.

What is fertilisation?

The joining of gametes to form a diploid zygote.

State one advantage of sexual reproduction.

It creates genetic variation, improving survival in changing environments.

Why is sexual reproduction energetically costly?

Energy is required to find a mate and produce gametes, and the process is slower.

Define genetic diversity.

The variety of genotypes (alleles) within a species or population.

What is the primary source of new alleles?

Mutations.

Why is genetic diversity important for species survival?

It allows populations to adapt to environmental changes and reduces extinction risk.

What are structural adaptations?

Physical features that aid survival, such as webbed feet or waxy cuticles.

Give an example of a physiological adaptation.

Camel’s ability to store water (or antifreeze proteins in plants).

What is a behavioural adaptation?

An inherited action, like migration, burrowing, or nocturnal activity, that helps survival.

Explain CAM photosynthesis.

A strategy where plants open stomata at night to reduce water loss.

Differentiate between mutualism and commensalism.

Mutualism benefits both species; commensalism benefits one without affecting the other.

What is parasitism?

One species benefits while the host is harmed.

Define intraspecific competition.

Competition between members of the same species.

What is interspecific competition?

Competition between different species.

State Gause’s Principle.

Two species cannot occupy the exact same niche indefinitely; one will outcompete the other.

What percentage of energy typically transfers from one trophic level to the next?

About 10%.

What is a producer?

An organism that makes its own food via photosynthesis or chemosynthesis.

What role do decomposers play?

They break down dead organic matter, recycling nutrients back to the ecosystem.

Define keystone species.

A species that has a disproportionately large impact on its ecosystem relative to its abundance.

Give an example of a keystone species and its role.

Sea otters control sea urchin populations, protecting kelp forests.

What can happen to an ecosystem when a keystone species is removed?

Major changes in structure and population balance can occur, reducing biodiversity.

What is carrying capacity?

The maximum population size an environment can sustainably support.

What is a niche?

The role and position a species has in its environment, including its habitat, resources, and interactions.