Week 13 Tuesday - endangered species

Learning Outcomes

• Describe differences in the two types of African elephants:

  • Two species: African Savanna Elephant (Loxodonta africana) and African Forest Elephant (L. cyclotis).

  • Differences in habitats: African Savanna elephants inhabit grasslands and savannas, while African Forest elephants are found in dense tropical forests.

  • Phenotypic differences: Savanna elephants are larger, have bigger tusks, and are lighter in color compared to the forest elephants which are smaller with straighter tusks and darker skin.

  • Reproductive cycles: Savanna elephants tend to have longer inter-calving intervals due to environmental factors; forest elephants may breed more frequently based on their habitat's resource distribution.

• Explain how elephants contribute to the health of ecosystems:

  • Elephants as keystone species that maintain ecosystem structure by creating pathways in forests, uprooting trees, which helps to shape the habitat for other species.

  • Nutrient recycling through dung which promotes plant growth and biodiversity.

  • Role in seed dispersal, facilitating the growth of a variety of plant species.

• Know the origin of the name, orangutan, and why they are unique among non-human apes:

  • The name 'orangutan' originates from the Malay words "orang" (person) and "hutan" (forest), meaning 'person of the forest.'

  • Unique for their solitary behavior compared to other apes; they spend most of their life in trees, are arboreal primates.

• Explain how sexual dimorphism is evident in orangutans:

  • Males are significantly larger than females, with larger body sizes, bigger faces, and often develop cheek pads and long hair.

  • Males are solitary while females are often seen with offspring, demonstrating a clear difference in social behavior.

• Describe where orangutans spend most of their time, the types of food they consume, and their lifespan:

  • Spend most of their lives in trees (arboreal lifestyle).

  • Primarily frugivorous, consuming fruits, but also eat leaves, bark, and occasionally insects.

  • Lifespan ranges from 30 to 40 years in the wild.

• Describe how koalas are able to consume leaves with toxic compounds and how the nutrient content affects their sleep cycle:

  • Koalas have specialized adaptations in their digestive system (a long caecum) to break down the tough eucalyptus leaves and detoxify compounds due to a high population of specialized gut bacteria.

  • Their diet is low in energy, leading them to have a low metabolic rate and necessitating long periods of sleep (up to 20-22 hours daily).

• Explain how marsupials differ from other mammals:

  • Marsupials give birth to relatively undeveloped young, which then continue to develop inside the pouch of the mother.

  • Gestation period is shorter than that of placental mammals; after birth, the young crawl into the pouch where they latch onto teats for nutrition.

• Describe the gestation and development of the young:

  • In koalas, the gestation period is approximately 34-36 days, followed by a prolonged pouch development phase lasting about 6-7 months.

  • Young consume a nutrient-rich substance known as pap, produced by the mother, which is essential for their growth due to its microbial content.

• Name the stages in the life cycle of a Monarch butterfly and their chance of survival as larvae:

  • Life cycle stages: Egg, First Instar, Second Instar, Third Instar, Fourth Instar, Fifth Instar, Chrysalis, Adult Butterfly.

  • Only about 5% survive to the adult stage due to various threats and predation.

• Describe differences between the breeding and migrating generations of Monarchs and the total distance traveled in an annual life cycle:

  • Breeding generations live 2-5 weeks, laying eggs and continuing the life cycle; Migrating generations can live up to 9 months and do not mate until they reach their overwintering grounds.

  • Monarch butterflies migrate over 2000 miles to Mexico, while breeding occurs in the northern regions (U.S. and Canada).

  • Predict how reproductive diapause contributes to their survival:

  • By entering a state of reproductive diapause, Monarchs conserve energy for migration rather than reproduction, which is crucial for survival during long migrations.

Animal Conservation Status

Elephants

• Species: African Savanna Elephant (Loxodonta africana), African Forest Elephant (L. cyclotis)

• Conservation Status:

  • Endangered (EN) and Critically Endangered (CR) according to IUCN.

• Population Decline: 60% decline in 50 years; 86% in 31 years due to habitat loss, human-wildlife conflict, and illegal wildlife trade/poaching.

Orangutans

• Species: Pongo (various species)

• Conservation Status: Critically Endangered (CR) according to IUCN.

• Population Decline: >50% decline in 40 years. Only 800 Tapanuli orangutans remain due to deforestation, hunting, and illegal trade.

• Genetic Diversity: Low genetic diversity is a concern for the Tapanuli population.

Koalas

• Species: Phascolarctos cinereus

• Conservation Status: Vulnerable (VU) according to IUCN.

• Population Decline: 50% decline in two populations over the last 20 years; over 4000 Koalas killed annually due to habitat loss, heat waves, drought, fires, and disease.

Monarch Butterflies

• Species: Danaus plexippus ssp. plexippus

• Conservation Status: Vulnerable (VU) according to IUCN as of 2023.

• Population Decline: 80-90% in 30 years primarily due to habitat loss from herbicides and pesticides, and climate change impacting life cycles.

IUCN Red List Overview

• Categories: Includes various risk categories from "Least Concern" to "Critically Endangered".

• Koalas were last assessed in 2014 and are currently listed as Vulnerable and undergoing population decline due to various environmental threats.

General Threats to Conservation

• Common threats affecting these species include habitat loss or degradation, climate change, disease, and human activities such as development and pollution. Awareness and conservation efforts are crucial to counteract these threats.