Environmental Science A - Unit 4 Exam Flashcards

Natural Selection and Evolution

• Natural selection is the process allowing living organisms to adapt and change over time.
• For natural selection to occur, a key condition is the production of more offspring than can survive, leading to competition.
• Genetic variation among individuals enhances the chances of survival and reproduction in changing environments.
• Fitness of an organism encompasses both its ability to survive and reproduce successfully.

Population Dynamics

• In a scenario with rabbits of varying coat colors, natural selection would favor brown rabbits, increasing their population due to reduced visibility to predators.

Biodiversity

• Biodiversity is defined as the variety of life on Earth, crucial for ecosystem resilience.
• A mutation is any alteration in the nucleotide sequence of an organism's genome, potentially affecting traits and functions.

Speciation

• Sympatric speciation occurs when two species, such as apple maggots and hawthorn maggots, evolve from a common ancestor while living in the same area without overlapping food sources.

Genetic Variation and Evolution

• Inbreeding reduces genetic variation, making populations less adaptable to environmental changes and hindering evolution.
• Genetic disorders are caused by mutations in genes or abnormalities in chromosomes.

Threats to Biodiversity

• Major causes of biodiversity loss include invasive species, climate change, and habitat fragmentation, which divides larger habitats into smaller, isolated areas.
• Habitat fragmentation disrupts the ecosystem and threatens species survival.

Invasive Species

• Invasive species, like kudzu and zebra mussels, are non-native organisms that can harm local ecosystems by outcompeting native species and disrupting food webs.
• The introduction of zebra mussels increases algal blooms, negatively impacting aquatic ecosystems by depleting essential nutrients.

Conservation Status

• A species is categorized as endangered when it faces a high risk of extinction in a specific area or globally, such as the Cross River gorilla with fewer than 2,500 mature individuals.

Endangered Species Act

• The Endangered Species Act is a program aimed at conserving endangered species and their habitats, protecting biodiversity.

Genetic Engineering and Gene Drive

• A gene drive is a technology that ensures a specific gene is inherited in future generations, potentially useful for eliminating invasive species or reducing pesticide use.
• Gene drives function by creating homozygous organisms for desired traits, enhancing their inheritance likelihood.

Inheritance Patterns

• In diploid organisms, genes are inherited from both parents, contributing to offspring genetic diversity and trait expression.

Test your understanding of natural selection and the conditions required for it to take place with these flashcards. This study tool covers key concepts in environmental science, specifically Unit 4. Get ready for your exam by reviewing these essential definitions and processes.