bio final Flashcards
What is a key characteristic of Lophotrochozoan?
Metamorphosis is present
This group includes various organisms that undergo significant developmental changes.
What are the four groups of Platyhelminthes (flatworms)?
- Majority are parasitic
- Most live inside the animal
- Parasites have to evolve with the host
- No circulatory, respiratory, or excretory system
- Vast majority carries both male and female reproductive organs
Platyhelminthes include various species that exhibit these characteristics.
Why are animal parasites considered successful?
- They have a very proactive life
- They have evolved immensely
- Can reproduce significantly
These factors contribute to their adaptability and survival.
Describe the reproductive behavior of fluke worms.
Female and male find each other in the human body; female attaches to the male for life and reproduces sexually by releasing fertilized eggs
This behavior is crucial for their life cycle and survival.
What is notable about tapeworms?
- They have been around for a long time
- Cestodes are a very diverse group
- They attach themselves in muscles
- Usually found in raw meat, fish, and poultry
Tapeworms have adapted to various hosts and environments.
What is unique about cone snails (Conus)?
- Diverse, mostly tropical (700 species)
- Serious predators (feeds on worms, snails, fish)
- Delivers venomous harpoon (200 m/sec)
- Venom has evolved phenotypically with up to 200 different types targeting specific cell receptors
Their venom is of interest for potential medical applications.
What are some properties of spider silk?
- Silks have evolved independently many times in arthropods
- Non-homologous
- Spider silks are made from a liquid to a solid state
- Different glands create different silks
- Spiders can regulate which gland produces which type of silk
Spider silk is known for its strength, extensibility, and toughness.
What is the significance of spider venom?
- Found in all spiders
- Up to 200 different venoms can be produced
- Each spider has a different venom composition
- Estimated 10-20 million different peptide molecules, with only 0.01% known for biochemical diversity
Many spiders are not venomous to humans, allowing for potential medical uses.
What is the two-fold cost of sex?
- Asexual population has female sex organs but does not mate with males
- Sexual population requires investment in energy, time, and safety
This concept highlights the evolutionary trade-offs between sexual and asexual reproduction.
What is a method of asexual reproduction represented in this content?
Budding
This is a process where a new organism develops from an outgrowth or bud on the parent.
What are totipotent cells responsible for?
Regenerating body cells (neoblasts)
These cells have the potential to develop into any cell type.
What is the difference between iteroparous and semelparous organisms?
- Iteroparous: reproduce multiple times in their life
- Semelparous: reproduce only once in a lifetime
These reproductive strategies have significant energy costs and implications for survival.
Provide an example of a semelparous organism.
Salmon
Salmon males repurpose body fat for the journey upstream to lay eggs and die afterward.
What is hermaphroditism?
100% individuals are male or female but can change into the other sex
An example is the California sheephead fish.
What is haplodiploidy?
Queens produce eggs: if fertilized, they are diploid females; if not, they are haploid males
This system is common in certain insect species, such as bees.
How do queens determine the sex of their offspring in haplodiploidy?
The queen decides if there is a need for females or males
This decision-making is crucial for the colony’s social structure.
What is shifting baseline syndrome?
Baseline changes over time, and all are valid depending on the current state of focus.
It reflects how perceptions of environmental conditions can change as ecosystems are altered.
How does sperm competition differ between lions and tigers?
Sperm developed faster in lions due to sperm to sperm competition.
This highlights the evolutionary adaptations related to reproductive success.
Are choanoflagellates considered animals?
No, choanoflagellates are not considered animals and tend to be unicellular.
They are closely related to animals but do not meet the criteria for classification.
What is the cellular structure of sponges?
Sponges are multicellular and share cells with choanoflagellates.
This relationship indicates evolutionary connections between the two groups.
What are the types of symmetry in animals?
Radial, bilateral, asymmetry, triradiate.
These symmetry types affect the organism’s body plan and evolutionary adaptations.
What is the difference between diploblastic and triploblastic organisms?
Diploblastic organisms have two germ layers, while triploblastic organisms have three.
The three layers include ectoderm, mesoderm, and endoderm.
What is the mesoderm?
The middle germ layer, last to evolve.
It plays a crucial role in the development of many organ systems.
