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Questions and Answers
State the purpose of a pyramid of energy, pyramid of numbers, and pyramid of biomass.
State the purpose of a pyramid of energy, pyramid of numbers, and pyramid of biomass.
The purpose of a pyramid of energy, pyramid of numbers, and pyramid of biomass is to represent the flow of energy, number of organisms, and the total mass of living organisms at different trophic levels in an ecosystem, respectively.
What is a food chain? Provide an example.
What is a food chain? Provide an example.
A food chain is a linear sequence of organisms where each is eaten by the next member in the chain. Example: Grass → Grasshopper → Frog → Snake → Hawk.
What is a food web? Explain with an example.
What is a food web? Explain with an example.
A food web is a complex network of interconnected food chains in an ecosystem. Example: A forest food web includes plants, herbivores, carnivores, and decomposers.
Why are food chains and food webs limited in the number of species they can support?
Why are food chains and food webs limited in the number of species they can support?
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Define 'Natural Selection' in the context of evolution.
Define 'Natural Selection' in the context of evolution.
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What is genetic drift?
What is genetic drift?
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Artificial selection involves humans breeding organisms for specific traits.
Artificial selection involves humans breeding organisms for specific traits.
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_____ is the role and position a species has in its environment, including all its interactions with biotic and abiotic factors.
_____ is the role and position a species has in its environment, including all its interactions with biotic and abiotic factors.
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Match the evidence of evolution with its description:
Match the evidence of evolution with its description:
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Explain the concept of 'Carrying capacity' in an ecosystem.
Explain the concept of 'Carrying capacity' in an ecosystem.
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What is the main difference between homologous and analogous structures?
What is the main difference between homologous and analogous structures?
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Study Notes
Evolution
- Species: A group of organisms that can interbreed and produce fertile offspring.
- Gene pool: The total collection of all genetic variations (alleles) within a population.
- Allele frequency: The proportion of a specific allele in a population, reflecting evolutionary changes influenced by natural selection, genetic drift, and mutation.
- Speciation: The evolutionary process by which populations evolve to become distinct species, typically due to genetic isolation from lack of gene flow.
- Genotype and phenotype: In evolution, genotype refers to an organism's genetic makeup, while phenotype describes the physical and behavioral traits expressed as a result of interacting genotypes and environmental factors.
- Gene flow: The exchange of genes between populations, enhancing genetic diversity and reducing population differences.
- Genetic drift: A random event that causes a drastic change in allele frequency.
- Genetic bottleneck: A sudden reduction in the size of a population due to environmental events or human activities, leading to a decrease in genetic diversity and altering the population's genetic structure.
Natural Selection and Artificial Selection
- Artificial selection: When humans breed organisms for specific traits, like breeding cows and sheep for their milk and wool.
- Natural selection: The natural process where organisms better adapted to their environment survive and reproduce more successfully.
Comparison of Lamarck's Theory and Darwin's Theory
- Lamarck's theory: Organisms pass on traits acquired during their lifetimes.
- Darwin's theory of evolution: Inherited genetic variations advantageous for survival are naturally selected over generations.
Mechanisms of Evolution
- Variation: Individuals in a population differ in a trait due to differences in their genotype and/or phenotype.
- Inheritance: Traits can be passed on through generations.
- Adaptation: A trait or behavior that helps an organism survive and reproduce in its specific environment.
- Mutation: Caused by a mutagen or random mistakes in germ cells or during meiosis.
- Differential survival and reproduction (survival of the fittest): How well an organism can survive and reproduce.
Evidences of Evolution
- Comparative anatomy: Similarities and differences in the evolutionary paths that organisms take, determining the family of a certain species.
- Comparative embryology: Study of embryos and their development, proving that development/evolution happens because traits and structures occur and go away after time.
- Biogeography: Study of the patterns of geographic distribution of organisms and the factors that determine those patterns.
- Biomolecular evidence (DNA): DNA sequences in different species share similarities, indicating common ancestry.
- Fossil record (including transitional and index fossils): Fossil record documents the gradual changes in species over time, with transitional fossils showing intermediate forms between species and index fossils helping date the strata.
Evolution in Humans
- Homo: Genus including all ancestors of humans.
- Sahelanthropus: One of the earliest known hominins, dated about 6-7 million years ago, notable for features that suggest bipedalism and a mix of ape-like and human-like traits.
- Ardipithecus: Genus of early hominins known for species like Ardipithecus ramidus.
- Australopithecus: Genus of hominins that lived from about 4 to 2 million years ago, known for bipedalism and a slightly larger brain than earlier hominins.
- Homo habilis: 2.4-1.5 mya, made simple chopper tools.
- Homo erectus: 1.8 mya-200,000 ya, made spears, hand axes, and cleavers, used fire, and built branched-huts.
- Homo neanderthalensis: Stocky with broad noses and adapted to cold climates, went extinct 40,000 ya.
- Homo sapiens: Intelligent and adaptable, invented agriculture 12,000 years ago, and settled in farming communities.
Ecology
- Species: A group of organisms that can interbreed and produce fertile offspring.
- Habitat: The natural environment where a species lives and grows.
- Population: A group of individuals of the same species living in a particular area.
- Community: All the different species that live together in a particular area.
- Ecosystem: A community of living organisms and their interactions with their abiotic (non-living) environment.
- Biocenosis: The interacting organisms living together in a habitat or ecosystem.
- Abiotic factor: Non-living chemical and physical parts of the environment.
- Biotic factor: Living components of an ecosystem.
- Limiting factor: A factor that restricts the growth, abundance, or distribution of a population.
- Carrying capacity: The maximum number of individuals of a species that an ecosystem can support.
- Ecological niche: The role and position a species has in its environment, including all its interactions with biotic and abiotic factors.
- Biome: A large geographical area characterized by specific climate conditions, plant communities, and animal populations.
- Biosphere: The global sum of all ecosystems, encompassing all living organisms and their interactions with the Earth's atmosphere, hydrosphere, and lithosphere.
Ecology (continued)
- Producer: Organisms that produce their own food through photosynthesis or chemosynthesis.
- Consumer: Organisms that obtain energy by eating other organisms.
- Autotroph: An organism that produces its own food from inorganic substances.
- Heterotroph: An organism that cannot produce its own food and consumes other organisms.
- Levels of energy production and consumption: primary, secondary, tertiary, quaternary.
- Herbivores: Animals that primarily eat plants.
- Carnivores: Animals that primarily eat meat (other animals).
- Omnivores: Animals that eat both plants and meat.
- Prey: Animals that are hunted and eaten by predators.
- Predators: Animals that hunt and eat other animals.
- Apex predators: Top predators in a food chain with no natural predators.
- Detritivores: Organisms that feed on dead organic matter and waste.
- Decomposers: Organisms that break down dead organisms and organic waste, recycling nutrients back into the ecosystem.
Trophic Levels and Energy Flow
- Trophic level: The position that an organism occupies in a food chain, or the position of a group of organisms in a community that occupy the same position in food chains.
- Energy flow: Only 10% of the energy within a level is passed on to the next higher trophic level.
Food Chains and Webs
- Food chain: A linear sequence of organisms where each is eaten by the next member in the chain.
- Food web: A complex network of interconnected food chains in an ecosystem.
Pyramids of Energy, Numbers, and Biomass
- Pyramid of energy: A graphical representation of the energy flow in an ecosystem, with the base being the producers and the apex being the apex predators.
- Pyramid of numbers: A graphical representation of the population sizes in an ecosystem, with the base being the producers and the apex being the apex predators.
- Pyramid of biomass: A graphical representation of the total biomass in an ecosystem, with the base being the producers and the apex being the apex predators.
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Description
Review key biology concepts for the grade 10 semester exam, including species, gene pool, allele frequency, and evolution. Prepare for your exam with this study guide!
