Biology: Plant Adaptations, Ecosystems, and Cellular Processes

What is a primary reason herbivores eat many different plant species?

Eating a variety of plants helps an herbivore ensure food is available even if one plant species becomes scarce.

Why is it crucial for higher-level consumers to be able to switch prey?

It allows them to survive if one prey population declines.

What is the '10% rule' in ecology?

The principle that energy transfer up the food chain is inefficient, with only about 10% of energy moving to the next trophic level.

What prevents organisms from growing without increased limits?

Environmental limiting factors such as limited populations of food, water, space, and disease.

What is the maximum size of a population an environment can support?

Carrying Capacity.

What are the two main categories of environmental constraints that restrict population size and growth?

Density-dependent and density-independent factors.

What are some examples of density-dependent limiting factors?

Competition for limited resources, Disease spreading more easily in a crowded population, and Predation increasing as prey become more abundant

What are some examples of density-independent limiting factors?

Natural disasters, extreme weather, human activities

What is the primary selective pressure that has led to an increase in tuskless elephants?

Ivory poaching, where elephants with tusks are killed, leaving tuskless ones to survive and reproduce.

What is a major advantage for an elephant to be tuskless in a region with poaching?

They are not targeted by poachers and are more likely to survive.

What is a disadvantage for an elephant for being tuskless?

They don't have tusks for defense against predators or for fighting other males for mates.

What two types of data are required from a tusk to track the origin of poached ivory?

DNA and isotope data.

How is genetic and isotopic data used to find the origin of poached ivory?

The information is compared against a database of known elephant populations to pinpoint the geographical match.

In the context of elephant evolution, what has poaching acted as?

A selective pressure favoring tuskless elephants.

What is a gene?

A segment of DNA found at a specific position on a chromosome that codes for a particular trait.

What are STRs (Short Tandem Repeats)?

Highly variable, non-coding loci on DNA where a specific number of DNA lines is repeated.

How are Short Tandem Repeats (STRs) used to identify the origin of poached ivory?

Scientists create a unique genetic profile based on the length of STR variants and compare it to a reference map of allele frequencies from known populations.

How does elephant foraging affect plant communities?

By clearing large areas of vegetation, they create gaps of sunlight that allow diverse species to grow.

Besides clearing vegetation, what are two other ways elephants benefit their plant-based ecosystem?

Their dung acts as a vital natural fertilizer, and they disperse seeds over long distances.

What are the eight characteristics that define life?

Response to stimuli, adaptation, reproduction, energy processing, homeostasis, organization, growth, and genetic material.

How can one differentiate a living organism from a non-living thing?

A living organism will exhibit all of the core characteristics of life.

Where does most plant growth, driven by rapidly dividing cells, occur?

In the meristems.

What plant process provides the necessary energy for growth?

Photosynthesis.

What biological process allows cells to mature and specialize to form different tissues and organs?

Cell differentiation.

How does the large, flat shape of a leaf support capturing sunlight?

It maximizes the surface area for photosynthesis.

What part of a plant cell absorbs light energy for photosynthesis?

Chloroplasts, which contain the pigment chlorophyll.

What is the function of stomata on a leaf?

To regulate the intake of carbon dioxide and the release of oxygen.

What plant tissue is responsible for supplying water and minerals from the roots to the rest of the plant?

Xylem.

What are the three essential raw materials needed for photosynthesis?

Carbon dioxide, water, and light energy.

How does a plant absorb carbon dioxide from the atmosphere?

It is absorbed through the stomata in the leaves.

What are the primary products of photosynthesis?

Glucose and oxygen.

What is the primary function of cellular respiration?

To use glucose and oxygen to release stored energy in the form of ATP.

How do photosynthesis and cellular respiration form a cycle?

The products of photosynthesis (glucose and oxygen) are the reactants for cellular respiration, and vice versa.

What two substances must be available for cellular respiration to occur?

Glucose and oxygen.

Why is temperature a crucial factor affecting the rate of cellular respiration?

It relies on enzymes that only function within a specific temperature range.

How do ATP levels regulate the rate of cellular respiration?

High ATP levels slow the process down, while low ATP levels speed it up to create more energy.

What is an autotroph?

An organism, such as a plant, that produces its own energy, typically through photosynthesis.

What is a heterotroph?

An organism, such as an animal, that gets energy by eating other organisms.

What process do both autotrophs and heterotrophs use to convert stored chemical energy into usable power?

Cellular respiration.

What is a gene

Inside the nucleus of a cell, there are chromosomes, and inside, there are strands of DNA, A gene is a strand of DNA

Gene

A gene is a strand of DNA that codes for a specific trait or function, and each individual has two copies of every gene from each parent.

Allele

A different variant or version of a gene. Each gene can have multiple alleles, but an individual carries only two, one from each parent.